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Test methods for evaluating solid waste, physical/chemical methods, method 8081b: organochlorine pesticides by gas chromatography

ORGANOCHLORINE PESTICIDES BY GAS CHROMATOGRAPHY SW-846 is not intended to be an analytical training manual. Therefore, method procedures are written based on the assumption that they will be performed by analysts who areformally trained in at least the basic principles of chemical analysis and in the use of the subjecttechnology.
In addition, SW-846 methods, with the exception of required method use for the analysis of method-defined parameters, are intended to be methods which contain general informationon how to perform an analytical procedure or technique, which a laboratory can use as a basicstarting point for generating its own detailed Standard Operating Procedure (SOP), either for itsown general use or for a specific project application. The performance data included in thismethod are for guidance purposes only, and are not intended to be and must not be used asabsolute QC acceptance criteria for purposes of laboratory accreditation.
1.0 SCOPE AND APPLICATION This method may be used to determine the concentrations of various organochlorine pesticides in extracts from solid and liquid matrices, using fused-silica, open-tubular, capillary columns with electron capture detectors (ECD) or electrolytic conductivitydetectors (ELCD). The following RCRA compounds have been determined by this methodusing either a single- or dual-column analysis system: CAS Registry No.a Chlordane -- not otherwise specified (n.o.s.) Endosulfan sulfate CAS Registry No.a Heptachlor epoxide aChemical Abstract Service Registry Number This method no longer includes PCBs as Aroclors in the list of target analytes. The analysis of PCBs should be undertaken using Method 8082, which includes specific cleanupand quantitation procedures designed for PCB analysis. This change was made to obtain PCBdata of better quality and to eliminate the complications inherent in a combined organochlorinepesticide and PCB method. Therefore, if the presence of PCBs is suspected, use Method 8082for PCB analyses, and this method (Method 8081) for organochlorine pesticide analyses. Ifthere is no information on the likely presence of PCBs, either employ a PCB-specific screeningprocedure such as an immunoassay (e.g., Method 4020), or split the sample extract prior to anycleanup steps, and process part of the extract for organochlorine pesticide analysis and theother portion for PCB analysis using Method 8082.
The analyst must select columns, detectors and calibration procedures most appropriate for the specific analytes of interest in a study. Matrix-specific performance datamust be established and the stability of the analytical system and instrument calibration must beestablished for each analytical matrix (e.g., hexane solutions from sample extractions, diluted oilsamples, etc.). Example chromatograms and GC conditions are provided as guidance.
Although performance data are presented for many of the target analytes, it is unlikely that all of them could be determined in a single analysis. The chemical andchromatographic behaviors of many of these chemicals can result in coelution of some targetanalytes. Several cleanup/fractionation schemes are provided in this method and in Method3600.
Several multi-component mixtures (i.e., chlordane and toxaphene) are listed as target analytes. When samples contain more than one multi-component analyte, a higher levelof analyst expertise is necessary to attain acceptable levels of qualitative and quantitativeanalysis. The same is true of multi-component analytes that have been subjected toenvironmental degradation or degradation by treatment technologies. These result in"weathered" multi-component mixtures that may have significant differences in peak patterns tothose of standards.
Compound identification based on single-column analysis should be confirmed on a second column, or should be supported by at least one other qualitative technique. Thismethod describes analytical conditions for a second gas chromatographic column that can beused to confirm the measurements made with the primary column. GC/MS (e.g., Method 8270)is also recommended as a confirmation technique, if sensitivity permits (also see Sec. 11.7 ofthis method). GC/AED may also be used as a confirmation technique, if sensitivity permits (seeMethod 8085).
This method includes a dual-column option that describes a hardware configuration in which two GC columns are connected to a single injection port and to twoseparate detectors. The option allows one injection to be used for dual-column simultaneousanalysis.
The following compounds may also be determined using this method. They have been grouped separately from the compounds in Sec. 1.1 because they have not been asextensively validated by EPA. If these compounds are to be determined using this procedure,the analyst is advised that additional efforts may be necessary in order to optimize theinstrument operating conditions and to demonstrate acceptable method performance.
CAS Registry No.
Permethrin (cis + trans) Kepone extracted from samples or in standards exposed to water or methanol may produce peaks with broad tails that elute later than the standard by up to 1 min. This shift ispresumably the result of the formation of a hemi-acetal from the ketone functionality and mayseriously affect the ability to identify this compound on the basis of its retention time. As aresult, this method is not recommended for determining Kepone. Method 8270 may be moreappropriate for the analysis of Kepone.
Extracts suitable for analysis by this method may also be analyzed for organophosphorus pesticides (Method 8141). Some extracts may also be suitable for triazineherbicide analysis, if low recoveries (normally samples taken for triazine analysis must bepreserved) are not a problem.
Prior to employing this method, analysts are advised to consult the base method for each type of procedure that may be employed in the overall analysis (e.g., Methods 3500,3600, and 8000) for additional information on quality control procedures, development of QCacceptance criteria, calculations, and general guidance. Analysts also should consult thedisclaimer statement at the front of the manual and the information in Chapter Two for guidanceon the intended flexibility in the choice of methods, apparatus, materials, reagents, andsupplies, and on the responsibilities of the analyst for demonstrating that the techniquesemployed are appropriate for the analytes of interest, in the matrix of interest, and at the levelsof concern.
In addition, analysts and data users are advised that, except where explicitly specified in a regulation, the use of SW-846 methods is not mandatory in response to Federal testingrequirements. The information contained in this method is provided by EPA as guidance to beused by the analyst and the regulated community in making judgments necessary to generateresults that meet the data quality objectives for the intended application.
Use of this method is restricted to use by, or under the supervision of, personnel appropriately experienced and trained in the use of gas chromatographs (GCs) and skilled inthe interpretation of gas chromatograms. Each analyst must demonstrate the ability to generateacceptable results with this method.
2.0 SUMMARY OF METHOD A measured volume or weight of liquid or solid sample is extracted using the appropriate matrix-specific sample extraction technique.
Aqueous samples may be extracted at neutral pH with methylene chloride using either Method 3510 (separatory funnel), Method 3520 (continuous liquid-liquidextractor), Method 3535 (solid-phase extraction), or other appropriate technique.
Solid samples may be extracted with hexane-acetone (1:1) or methylene chloride-acetone (1:1) using Method 3540 (Soxhlet), Method 3541 (automated Soxhlet),Method 3545 (pressurized fluid extraction), Method 3546 (microwave extraction), Method3550 (ultrasonic extraction), Method 3562 (supercritical fluid extraction), or otherappropriate technique or solvents.
A variety of cleanup steps may be applied to the extract, depending on the nature of the matrix interferences and the target analytes. Suggested cleanups include alumina(Method 3610), Florisil (Method 3620), silica gel (Method 3630), gel permeationchromatography (Method 3640), and sulfur (Method 3660).
After cleanup, the extract is analyzed by injecting a measured aliquot into a gas chromatograph equipped with either a narrow-bore or wide-bore fused-silica capillary column,and either an electron capture detector (GC/ECD) or an electrolytic conductivity detector(GC/ELCD).
Refer to Chapter One and the manufacturer's instructions for definitions that may be relevant to this procedure.
4.0 INTERFERENCES Solvents, reagents, glassware, and other sample processing hardware may yield artifacts and/or interferences to sample analysis. All of these materials must be demonstratedto be free from interferences under the conditions of the analysis by analyzing method blanks. Specific selection of reagents and purification of solvents by distillation in all-glass systems maybe necessary. Refer to each method to be used for specific guidance on quality controlprocedures and to the chapter text for general guidance on the cleaning of glassware. Alsorefer to Methods 3500, 3600, and 8000 for a discussion of interferences.
Interferences co-extracted from the samples will vary considerably from waste to waste. While general cleanup techniques are referenced or provided as part of this method,unique samples may require additional cleanup approaches to achieve desired degrees ofdiscrimination and quantitation. Sources of interference in this method can be grouped intothree broad categories, as follows.
Contaminated solvents, reagents, or sample processing hardware.
Contaminated GC carrier gas, parts, column surfaces, or detector Compounds extracted from the sample matrix to which the detector will Interferences by phthalate esters introduced during sample preparation can pose a major problem in pesticide determinations. Interferences from phthalate esters can best beminimized by avoiding contact with any plastic materials and checking all solvents and reagentsfor phthalate contamination.
Common flexible plastics contain varying amounts of phthalate esters which are easily extracted or leached from such materials during laboratory operations.
Exhaustive cleanup of solvents, reagents and glassware may be necessary to eliminate background phthalate ester contamination.
These materials may be removed prior to analysis using Method 3640 (Gel Permeation Cleanup) or Method 3630 (Silica Gel Cleanup).
Cross-contamination of clean glassware routinely occurs when plastics are handled during extraction steps, especially when solvent-wetted surfaces are handled. Glassware must be scrupulously cleaned.
Clean all glassware as soon as possible after use by rinsing with the last solvent used. This should be followed by detergent washing with hot water, and rinses with tap water andorganic-free reagent water. Drain the glassware and dry it in an oven at 130 EC for several hours, or rinse with methanol and drain. Store dry glassware in a clean environment. (Otherappropriate glassware cleaning procedures may be employed.) The presence of sulfur will result in broad peaks that interfere with the detection of early-eluting organochlorine pesticides. Sulfur contamination should be expected with sedimentsamples. Method 3660 is suggested for removal of sulfur. Since the recovery of endrinaldehyde is drastically reduced when using the TBA procedure in Method 3660, this compoundmust be determined prior to sulfur cleanup when it is an analyte of interest and the TBAprocedure is to be used for cleanup. Endrin aldehyde is not affected by the copper powder, soendrin aldehyde can be determined after the removal of sulfur using the copper powdertechnique in Method 3660. However, as indicated in Method 3660, the use of copper powdermay adversely affect the recoveries of other potential analytes of interest, including someorganochlorine compounds and many organophosphorous compounds.
Waxes, lipids, and other high molecular weight materials can be removed by gel permeation chromatography (GPC) cleanup (Method 3640).
Other halogenated pesticides or industrial chemicals may interfere with the analysis of pesticides. Certain coeluting organophosphorus pesticides may be eliminated usingMethod 3640 (GPC -- pesticide option). Coeluting chlorophenols may be eliminated by usingMethod 3630 (silica gel), Method 3620 (Florisil), or Method 3610 (alumina). Polychlorinatedbiphenyls (PCBs) also may interfere with the analysis of the organochlorine pesticides. Theproblem may be most severe for the analysis of multicomponent analytes such as chlordane,toxaphene, and Strobane. If PCBs are known or expected to occur in samples, the analystshould consult Methods 3620 and 3630 for techniques that may be used to separate thepesticides from the PCBs.
Coelution among the many target analytes in this method can cause interference problems. The following target analytes may coelute on the GC columns listed, when using thesingle-column analysis scheme: The following compounds may coelute using the dual-column analysis scheme. In general, the DB-5 column resolves fewer compounds than the DB-1701.
Nitrofen, dichlone, carbophenothion, and dichloran exhibit extensive peak tailing on both columns. Simazine and atrazine give poor responses on the ECD detector. Triazine compounds should be analyzed using Method 8141 (nitrogen-phosphorus detector, or NPD,option). This method does not address all safety issues associated with its use. The laboratory is responsible for maintaining a safe work environment and a current awareness file of OSHAregulations regarding the safe handling of the chemicals listed in this method. A reference fileof material safety data sheets (MSDSs) should be available to all personnel involved in theseanalyses.
6.0 EQUIPMENT AND SUPPLIES The mention of trade names or commercial products in this manual is for illustrative purposes only, and does not constitute an EPA endorsement or exclusive recommendation foruse. The products and instrument settings cited in SW-846 methods represent those productsand settings used during method development or subsequently evaluated by the Agency. Glassware, reagents, supplies, equipment, and settings other than those listed in this manualmay be employed provided that method performance appropriate for the intended applicationhas been demonstrated and documented. This section does not list common laboratory glassware (e.g., beakers and flasks).
Gas chromatograph (GC) -- An analytical system complete with gas chromatograph suitable for on-column and split-splitless injection and all necessary accessoriesincluding syringes, analytical columns, gases, electron capture detectors (ECD), andrecorder/integrator or data system. Electrolytic conductivity detectors (ELCD) may also beemployed if appropriate for project needs. If the dual-column option is employed, the gaschromatograph must be equipped with two detectors.
This method describes procedures for both single-column and dual-column analyses. The single-column approach involves one analysis to determine that a compound is present,followed by a second analysis to confirm the identity of the compound (Sec. 11.7 describes howGC/MS confirmation techniques may be employed). The single-column approach may employeither narrow-bore (#0.32-mm ID) columns or wide-bore (0.53-mm ID) columns. The dual- column approach generally employs a single injection that is split between two columns that aremounted in a single gas chromatograph. The dual-column approach generally employs wide-bore (0.53-mm ID) columns, but columns of other diameters may be employed if the analyst candemonstrate and document acceptable performance for the intended application. A thirdalternative is to employ dual columns mounted in a single GC, but with each column connectedto a separate injector and a separate detector.
The columns listed in this section were the columns used in developing the method. The listing of these columns in this method is not intended to exclude the use of other columns thatare available or that may be developed. Laboratories may use these columns or other columnsprovided that the laboratories document method performance data (e.g., chromatographicresolution, analyte breakdown, and sensitivity) that are appropriate for the intended application.
Narrow-bore columns for single-column analysis (use both columns to confirm compound identifications unless another confirmation technique such as GC/MS is employed). Narrow-bore columns should be installed in split/splitless (Grob-type)injectors. 30-m x 0.25-mm or 0.32-mm ID fused-silica capillary column chemically bonded with SE-54 (DB-5 or equivalent), 1-µm film thickness.
30-m x 0.25-mm ID fused-silica capillary column chemically bonded with 35 percent phenyl methylpolysiloxane (DB-608, SPB-608, orequivalent), 2.5 µm coating thickness, 1-µm film thickness.
Wide-bore columns for single-column analysis (use two of the three columns listed to confirm compound identifications unless another confirmation techniquesuch as GC/MS is employed). Wide-bore columns should be installed in 1/4-inchinjectors, with deactivated liners designed specifically for use with these columns.
30-m x 0.53-mm ID fused-silica capillary column chemically bonded with 35 percent phenyl methylpolysiloxane (DB-608, SPB-608, RTx-35, orequivalent), 0.5-µm or 0.83-µm film thickness.
30-m x 0.53-mm ID fused-silica capillary column chemically bonded with 50 percent phenyl methylpolysiloxane (DB-1701, or equivalent), 1.0-µm film thickness.
30-m x 0.53-mm ID fused-silica capillary column chemically bonded with 95 percent dimethyl - 5 percent diphenyl polysiloxane (DB-5, SPB-5,RTx-5, or equivalent), 1.5-µm film thickness.
Wide-bore columns for dual-column analysis -- The two pairs of recommended columns are listed below.
30-m x 0.53-mm ID fused-silica capillary column chemically bonded with SE-54 (DB-5, SPB-5, RTx-5, or equivalent), 1.5-µm film thickness.
30-m x 0.53-mm ID fused-silica capillary column chemically bonded with 50 percent phenyl methylpolysiloxane (DB-1701, or equivalent), 1.0-µm filmthickness.
Column pair 1 is mounted in a press-fit Y-shaped glass 3-way union splitter (J&W Scientific, Catalog No. 705-0733) or a Y-shaped fused-silicaconnector (Restek, Catalog No. 20405), or equivalent.
NOTE: When connecting columns to a press-fit Y-shaped connector, a better seal may be achieved by first soaking the ends of the capillary columns inalcohol for about 10 sec to soften the polyimide coating.
30-m x 0.53-mm ID fused-silica capillary column chemically bonded with SE-54 (DB-5, SPB-5, RTx-5, or equivalent), 0.83-µm film thickness. 30-m x 0.53-mm ID fused-silica capillary column chemically bonded with 50 percent phenyl methylpolysiloxane (DB-1701, or equivalent), 1.0-µm filmthickness.
Column pair 2 is mounted in an 8-inch deactivated glass injection tee (Supelco, Catalog No. 2-3665M, or equivalent).
Column rinsing kit -- Bonded-phase column rinse kit (J&W Scientific, Catalog No.
430-3000), or equivalent.
Volumetric flasks, 10-mL and 25-mL, for preparation of standards.
Analytical balance, capable of weighing to 0.0100 g.
7.0 REAGENTS AND STANDARDS Reagent-grade or pesticide-grade chemicals must be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to specifications of the Committeeon Analytical Reagents of the American Chemical Society, where such specifications areavailable. Other grades may be used, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening the accuracy of the determination. Reagents should be stored in glass to prevent the leaching of contaminants from plasticcontainers.
NOTE: Store the standard solutions (stock, composite, calibration, internal, and surrogate) at #6 EC in polytetrafluoroethylene (PTFE)-sealed containers, in the dark. When a lot of standards is prepared, aliquots of that lot should be stored in individual small vials. Allstock standard solutions must be replaced after one year, or sooner if routine QC (seeSec. 9.0) indicates a problem. All other standard solutions must be replaced after sixmonths, or sooner if routine QC (see Sec. 9.0) indicates a problem.
Solvents used in the extraction and cleanup procedures (see appropriate 3500 and 3600 series methods) include n-hexane, diethyl ether, methylene chloride, acetone, ethylacetate, and isooctane (2,2,4-trimethylpentane) and the solvents must be exchanged to n-hexane or isooctane prior to analysis. Therefore, the use of n-hexane and isooctane will berequired in this procedure. All solvents should be pesticide grade in quality or equivalent, andeach lot of solvent should be determined to be free of phthalates.
The following solvents may be necessary for the preparation of standards. All solvent lots must be pesticide grade in quality or equivalent and should be determined to be freeof phthalates.
Acetone, (CH ) CO Organic-free reagent water -- All references to water in this method refer to organic-free reagent water as defined in Chapter One.
Standard solutions The following sections describe the preparation of stock, intermediate, and working standards for the compounds of interest. This discussion is provided as an example, and other approaches and concentrations of the target compounds may be used, as appropriate for theintended application. See Method 8000 for additional information on the preparation ofcalibration standards. Stock standard solutions (1000 mg/L) -- May be prepared from pure standard materials or can be purchased as certified solutions.
Prepare stock standard solutions by accurately weighing 0.0100 g of pure compound. Dissolve the compound in isooctane or hexane and dilute to volume in a 10-mL volumetric flask. If compound purity is 96 percent or greater, the weight can be usedwithout correction to calculate the concentration of the stock standard solution. Commercially prepared stock standard solutions can be used at any concentration if theyare certified by the manufacturer or by an independent source.
β-BHC, dieldrin, and some other standards may not be adequately soluble in isooctane. A small amount of acetone or toluene should be used to dissolvethese compounds during the preparation of the stock standard solutions.
Composite stock standard -- May be prepared from individual stock solutions.
For composite stock standards containing less than 25 components, take exactly 1 mL of each individual stock solution at a concentration of 1000 mg/L, addsolvent, and mix the solutions in a 25-mL volumetric flask. For example, for a compositecontaining 20 individual standards, the resulting concentration of each component in themixture, after the volume is adjusted to 25 mL, will be 1 mg/25 mL. This compositesolution can be further diluted to obtain the desired concentrations.
For composite stock standards containing more than 25 components, use volumetric flasks of the appropriate volume (e.g., 50-mL, 100-mL), and follow theprocedure described above.
Calibration standards -- Should be prepared at a minimum of five different concentrations by dilution of the composite stock standard with isooctane or hexane. Theconcentrations should correspond to the expected range of concentrations found in realsamples and should bracket the linear range of the detector. See Method 8000 for additionalinformation on the preparation of calibration standards.
Although all single component analytes can be resolved on a new 35 percent phenyl methyl silicone column (e.g., DB-608), two calibration mixtures should beprepared for the single component analytes of this method. This procedure is establishedto minimize potential resolution and quantitation problems on confirmation columns or onolder 35 percent phenyl methyl silicone (e.g. DB-608) columns and to allow determinationof endrin and DDT breakdown for instrument quality control (Sec. 9.0). Separate calibration standards are necessary for each multi-component target analyte (e.g., toxaphene and chlordane). Analysts should evaluate the specifictoxaphene standard carefully. Some toxaphene components, particularly the more heavilychlorinated components, are subject to dechlorination reactions. As a result, standardsfrom different vendors may exhibit marked differences which could lead to possible falsenegative results or to large differences in quantitative results.
Internal standard (optional) Pentachloronitrobenzene is suggested as an internal standard for the single-column analysis, when it is not considered to be a target analyte. 1-Bromo-2-nitrobenzene may also be used. Prepare a solution of 5000 mg/L (5000 ng/µL) ofpentachloronitrobenzene or 1-bromo-2-nitrobenzene. Spike 10 µL of this solution intoeach 1 mL of sample extract.
1-Bromo-2-nitrobenzene is suggested as an internal standard for the dual-column analysis. Prepare a solution of 5000 mg/L (5000 ng/µL) of 1-bromo-2-nitrobenzene. Spike 10 µL of this solution into each 1 mL of sample extract. Surrogate standards The performance of the method should be monitored using surrogate compounds. Surrogate standards are added to all samples, method blanks, matrix spikes, andcalibration standards. The following compounds are recommended as possiblesurrogates. Other surrogates may be used, provided that the analyst can demonstrateand document performance appropriate for the data quality needs of the particularapplication.
Decachlorobiphenyl and tetrachloro-m-xylene have been found to be a useful pair of surrogates for both the single-column and dual-column configurations. Method 3500 describes the procedures for preparing these surrogates.
4-Chloro-3-nitrobenzotrifluoride may also be useful as a surrogate if the chromatographic conditions of the dual-column configuration cannot be adjusted topreclude coelution of a target analyte with either of the surrogates in Sec. 7.9.1. However,this compound elutes early in the chromatographic run and may be subject to otherinterference problems. A recommended concentration for this surrogate is 500 ng/µL. Use a spiking volume of 100 µL for a 1-L aqueous sample. (Other surrogateconcentrations may be used, as appropriate for the intended application.) Store surrogate spiking solutions at #6 EC in PTFE-sealed containers in 8.0 SAMPLE COLLECTION, PRESERVATION, AND STORAGE See the introductory material to Chapter Four, "Organic Analytes." Extracts must be stored under refrigeration in the dark and should be analyzed within 40 days of extraction.
9.0 QUALITY CONTROL Refer to Chapter One for guidance on quality assurance (QA) and quality control (QC) protocols. When inconsistencies exist between QC guidelines, method-specific QCcriteria take precedence over both technique-specific criteria and those criteria given in ChapterOne, and technique-specific QC criteria take precedence over the criteria in Chapter One. Anyeffort involving the collection of analytical data should include development of a structured andsystematic planning document, such as a Quality Assurance Project Plan (QAPP) or a Samplingand Analysis Plan (SAP), which translates project objectives and specifications into directions for those that will implement the project and assess the results. Each laboratory shouldmaintain a formal quality assurance program. The laboratory should also maintain records todocument the quality of the data generated. All data sheets and quality control data should bemaintained for reference or inspection. Refer to Method 8000 for specific determinative method QC procedures. Refer to Method 3500 for QC procedures to ensure the proper operation of the various samplepreparation techniques. If an extract cleanup procedure is performed, refer to Method 3600 forthe appropriate QC procedures. Any more specific quality control procedures provided in thismethod will supersede those noted in Methods 8000, 3500, or 3600.
Quality control procedures necessary to evaluate the GC system operation are found in Method 8000 and include evaluation of retention time windows, calibration verification,and chromatographic analysis of samples.
Include a calibration standard after each group of 20 samples (it is recommended that a calibration standard be included after every 10 samples to minimizethe number of repeat injections) in the analysis sequence as a calibration check. Thus,injections of method blank extracts, matrix spike samples, and other non-standards arecounted in the total. Solvent blanks, injected as a check on cross-contamination, need notbe counted in the total. The response factors for the calibration verification standardshould be within ±20% of the initial calibration (see Sec. 11.5.2). When this calibrationverification standard falls out of this acceptance window, the laboratory should stopanalyses and take corrective action.
Whenever quantitation is accomplished using an internal standard, internal standards must be evaluated for acceptance. The measured area of the internalstandard must be no more than 50 percent different from the average area calculatedduring initial calibration. When the internal standard peak area is outside the limit, allsamples that fall outside the QC criteria must be reanalyzed. The retention times of theinternal standards must also be evaluated. A retention time shift of >30 sec necessitatesreanalysis of the affected sample.
DDT and endrin are easily degraded in the injection port. Breakdown occurs when the injection port liner is contaminated with high boiling residue from sampleinjection or when the injector contains metal fittings. Check for degradation problems byinjecting a standard containing only 4,4'-DDT and endrin. Presence of 4,4'-DDE, 4,4'-DDD, endrin ketone or endrin indicates breakdown. If degradation of either DDT or endrinexceeds 15%, take corrective action before proceeding with calibration. Unless otherwisespecified in an approved project plan, this test should be performed even when DDT andendrin are not target analytes for a given project, as a test of the inertness of the analyticalsystem.
Calculate percent breakdown as follows: % breakdown of DDT sum of degradation peak areas (DDD % DDE) sum of all peak areas (DDT % DDE % DDD) % breakdown of endrin sum of degradation peak areas (aldehyde % ketone) sum of all peak areas (endrin % aldehyde % ketone) The breakdown of DDT and endrin should be measured before samples are analyzed and at the beginning of each 12-hr shift. Injectormaintenance and recalibration should be completed (see Sec. 11.9.2) if thebreakdown is greater than 15% for either compound.
Whenever silica gel (Method 3630) or Florisil® (Method 3620) cleanups are used, the analyst must demonstrate that the fractionation scheme is reproducible. Batch to batch variation in the composition of the silica gel or Florisil® or overloading thecolumn may cause a change in the distribution patterns of the organochlorine pesticides. When compounds are found in two fractions, add the concentrations found in the fractions,and correct for any additional dilution.
Initial demonstration of proficiency Each laboratory must demonstrate initial proficiency with each sample preparation and determinative method combination it utilizes, by generating data ofacceptable accuracy and precision for target analytes in a clean matrix. If an autosampleris used to perform sample dilutions, before using the autosampler to dilute samples, thelaboratory should satisfy itself that those dilutions are of equivalent or better accuracy thanis achieved by an experienced analyst performing manual dilutions. The laboratory mustalso repeat the demonstration of proficiency whenever new staff members are trained orsignificant changes in instrumentation are made. See Method 8000 for information onhow to accomplish a demonstration of proficiency.
It is suggested that the QC reference sample concentrate (as discussed in Methods 8000 and 3500) contain each analyte of interest at 10 mg/L in the concentrate. A 1-mL spike of this concentrate into 1 L of reagent water will yield a sample concentrationof 10 µg/L. If this method is to be used for analysis of chlordane or toxaphene only, theQC reference sample concentrate should contain the most representative multi-component mixture at a suggested concentration of 50 mg/L in acetone. See Method8000 for additional information on how to accomplish this demonstration. Otherconcentrations may be used, as appropriate for the intended application.
Calculate the average recovery and the standard deviation of the recoveries of the analytes in each of the four QC reference samples. Refer to Method8000 for procedures for evaluating method performance.
Initially, before processing any samples, the analyst should demonstrate that all parts of the equipment in contact with the sample and reagents are interference-free. This isaccomplished through the analysis of a method blank. As a continuing check, each timesamples are extracted, cleaned up, and analyzed, and when there is a change in reagents, amethod blank should be prepared and analyzed for the compounds of interest as a safeguardagainst chronic laboratory contamination. If a peak is observed within the retention time windowof any analyte that would prevent the determination of that analyte, determine the source andeliminate it, if possible, before processing the samples. The blanks should be carried throughall stages of sample preparation and analysis. When new reagents or chemicals are received,the laboratory should monitor the preparation and/or analysis blanks associated with samplesfor any signs of contamination. It is not necessary to test every new batch of reagents orchemicals prior to sample preparation if the source shows no prior problems. However, if reagents are changed during a preparation batch, separate blanks need to be prepared for eachset of reagents.
Sample quality control for preparation and analysis The laboratory must also have procedures for documenting the effect of the matrix on method performance (precision, accuracy. method sensitivity). At a minimum, this shouldinclude the analysis of QC samples including a method blank, a matrix spike, a duplicate, and alaboratory control sample (LCS) in each analytical batch and the addition of surrogates to eachfield sample and QC sample when surrogates are used. Any method blanks, matrix spikesamples, and replicate samples should be subjected to the same analytical procedures (Sec.
11.0) as those used on actual samples. Documenting the effect of the matrix should include the analysis of at least one matrix spike and one duplicate unspiked sample or one matrix spike/matrix spikeduplicate pair. The decision on whether to prepare and analyze duplicate samples or amatrix spike/matrix spike duplicate must be based on a knowledge of the samples in thesample batch. If samples are expected to contain target analytes, then laboratories mayuse a matrix spike and a duplicate analysis of an unspiked field sample. If samples arenot expected to contain target analytes, the laboratories should use a matrix spike andmatrix spike duplicate pair. Consult Method 8000 for information on developingacceptance criteria for the MS/MSD.
A laboratory control sample (LCS) should be included with each analytical batch. The LCS consists of an aliquot of a clean (control) matrix similar to the samplematrix and of the same weight or volume. The LCS is spiked with the same analytes atthe same concentrations as the matrix spike, when appropriate. When the results of thematrix spike analysis indicate a potential problem due to the sample matrix itself, the LCSresults are used to verify that the laboratory can perform the analysis in a clean matrix. Consult Method 8000 for information on developing acceptance criteria for the LCS.
Also see Method 8000 for the details on carrying out sample quality control procedures for preparation and analysis. In-house method performance criteria forevaluating method performance should be developed using the guidance found in Method8000.
Surrogate recoveries If surrogates are used, the laboratory should evaluate surrogate recovery data from individual samples versus the surrogate control limits developed by the laboratory. See Method8000 for information on evaluating surrogate data and developing and updating surrogate limits. Procedures for evaluating the recoveries of multiple surrogates and the associated correctiveactions should be defined in an approved project plan.
It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon theneeds of the laboratory and the nature of the samples. Whenever possible, the laboratoryshould analyze standard reference materials and participate in relevant performance evaluationstudies.
10.0 CALIBRATION AND STANDARDIZATION See Sec 11.0 for information on calibration and standardization.
Sample extraction Refer to Chapter Two and Method 3500 for guidance in choosing the appropriate extraction procedure. In general, water samples are extracted at a neutral pH withmethylene chloride using a separatory funnel (Method 3510), a continuous liquid-liquidextractor (Method 3520), solid-phase extraction (Method 3535), or other appropriatetechnique. Solid samples are extracted with hexane-acetone (1:1) or methylene chloride-acetone (1:1) using one of the Soxhlet extraction methods (Method 3540 or 3541),pressurized fluid extraction (Method 3545), microwave extraction (Method 3546),ultrasonic extraction (Method 3550), or other appropriate technique. Solid samples mayalso be extracted using supercritical fluid extraction (Method 3562). NOTE: Hexane-acetone (1:1) may be more effective than methylene chloride-acetone (1:1) as an extraction solvent for organochlorine pesticides in someenvironmental and waste matrices. Relative to the methylene chloride-acetonemixture, the use of hexane-acetone generally reduces the amount ofinterferences that are extracted and improves the signal-to-noise ratio.
The choice of extraction solvent will depend on the analytes of interest. No single solvent or extraction procedure is universally applicable to all analyte groups and samplematrices. The analyst must demonstrate adequate performance for the analytes ofinterest, at the levels of interest, for any solvent system employed, including thosespecifically listed in this method. At a minimum, such a demonstration will encompass theinitial demonstration of proficiency described in Method 3500, using a clean referencematrix. Each new sample type must be spiked with the compounds of interest todetermine the percent recovery. Method 8000 describes procedures that may be used todevelop performance criteria for such demonstrations as well as for matrix spike andlaboratory control sample results.
Cleanup procedures may not be necessary for a relatively clean sample matrix, but most extracts from environmental and waste samples will require additional preparationbefore analysis. The specific cleanup procedure used will depend on the nature of thesample to be analyzed and the data quality objectives for the measurements. Generalguidance for sample extract cleanup is provided in this section and in Method 3600.
If a sample is of biological origin, or contains high molecular weight materials, the use of Method 3640 (GPC -- pesticide option) is recommended. Frequently,one of the adsorption chromatographic cleanups (alumina, silica gel, or Florisil®) may alsobe necessary following the GPC cleanup.
Method 3610 (alumina) may be used to remove phthalate esters.
Method 3620 (Florisil®) may be used to separate organochlorine pesticides from aliphatic compounds, aromatics, and nitrogen-containing compounds.
Method 3630 (silica gel) may be used to separate single component organochlorine pesticides from some interferants.
Sulfur, which may be present in certain sediments and industrial wastes, interferes with the electron capture gas chromatography of certain pesticides. Sulfurshould be removed by the technique described in Method 3660.
This method allows the analyst to choose between a single-column or a dual-column configuration in the injector port. The columns listed in this section were the columns used todevelop the method performance data. The listing of these columns in this method is notintended to exclude the use of other columns that are available or that may be developed. Wide-bore or narrow-bore columns may be used with either option. Laboratories may use theseor other capillary columns or columns of other dimensions, provided that the laboratoriesdocument method performance data (e.g., chromatographic resolution, analyte breakdown, andsensitivity) that are appropriate for the intended application.
Single-column analysis This capillary GC/ECD method allows the analyst the option of using 0.25 or 0.32- mm ID capillary columns (narrow-bore) or 0.53-mm ID capillary columns (wide-bore). Performance data are provided for both options. Figures 1 - 6 provide examplechromatograms. Narrow-bore columns generally provide greater chromatographic resolution than wide-bore columns, although narrow-borecolumns have a lower sample capacity. As a result, narrow-bore columns may bemore suitable for relatively clean samples or for extracts that have been preparedwith one or more of the clean-up options referenced in the method. Wide-borecolumns (0.53-mm ID) may be more suitable for more complex environmental andwaste matrices. However, the choice of the appropriate column diameter is left toprofessional judgement of the analyst.
Table 1 lists example retention times for the target analytes using wide-bore capillary columns. Table 2 lists example retention times for thetarget analytes using narrow-bore capillary columns. The retention times listed inthese tables are provided for illustrative purposes only. Each laboratory mustdetermine retention times and retention time windows for their specific applicationof the method.
Table 3 lists suggested GC operating conditions for the single- column method of analysis.
Dual-column analysis The dual-column/dual-detector approach recommends the use of two 30-m x 0.53- mm ID fused-silica open-tubular columns of different polarities, thus of differentselectivities toward the target analytes. The columns are connected to an injection teeand separate electron capture detectors or to both separate injectors and separatedetectors. However, the choice of the appropriate column dimensions is left to theprofessional judgement of the analyst.
Example retention times for the organochlorine analytes on dual-columns are provided in Table 5. The retention times listed in the table areprovided for illustrative purposes only. Each laboratory must determine retentiontimes and retention time windows for their specific application of the method. The suggested GC operating conditions for the compounds in Table 5 are given inTable 6.
Multi-component mixtures of toxaphene and Strobane were analyzed separately (Figures 4 and 5) using the operating conditions in Table 6.
Figure 6 is an example chromatogram for a mixture of organochlorine pesticides. The retention times of the individual componentsdetected in these mixtures are given in Table 5, and are provided as examples. Suggested operating conditions for a more heavily loaded DB- 5/DB-1701 pair are given in Table 7. This column pair was used for the detectionof multi-component organochlorine compounds.
Suggested operating conditions for a DB-5/DB-1701 column pair having thinner films, a different type of splitter, and a slower temperatureprogramming rate are provided in Table 6. These conditions gave better peakshapes for nitrofen and dicofol. Table 5 lists the retention times for the compoundson this column pair.
Prepare calibration standards using the procedures in Sec. 7.0. Refer to Method 8000 and Sec. 9.3 of this method for proper calibration techniques for both initialcalibration and calibration verification. The procedure for either internal or externalcalibration may be used. In most cases, external standard calibration is used with thismethod because of the sensitivity of the electron capture detector and the probability ofthe internal standard being affected by interferences. Because several of the pesticidesmay coelute on any single column (see Sec. 4.8), analysts should use two calibrationmixtures. The specific mixture should be selected to minimize the problem of peakoverlap.
NOTE: Because of the sensitivity of the electron capture detector, always clean the injection port and column prior to performing the initial calibration.
Unless otherwise necessary for a specific project, the analysis of the multi-component analytes employs a single-point calibration. A singlecalibration standard near the mid-point of the expected calibration range of eachmulti-component analyte is included with the initial calibration of the singlecomponent analytes for pattern recognition, so that the analyst is familiar with thepatterns and retention times on each column. The calibration standard may be at alower concentration than the mid-point of the expected range, if appropriate for theproject.
For calibration verification (each 12-hr shift), all target analytes specified in the project plan must be injected.
Establish the GC operating conditions appropriate for the configuration (single-column or dual column, see Sec. 11.3) using as guidance and as appropriate theoperating condition information found in Tables 3, 4, 6, or 7. Optimize the instrumentalconditions for resolution of the target analytes and sensitivity. An initial oven temperatureof < 140 - 150 EC may be necessary to resolve the four BHC isomers. A final temperature of between 240 EC and 270 EC may be necessary to elute decachlorobiphenyl. The use of injector pressure programming will improve the chromatography of late eluting peaks.
NOTE: Once established, the same operating conditions must be used for both calibrations and sample analyses.
A 2-µL injection volume of each calibration standard is recommended. Other injection volumes may be employed, provided that the analyst can demonstrateadequate sensitivity for the compounds of interest.
Because of the low concentration of pesticide standards injected on a GC/ECD, column adsorption may be a problem when the GC has not been used for a dayor more. Therefore, the GC column should be primed (or deactivated) by injecting apesticide standard mixture approximately 20 times more concentrated than the mid-concentration standard. Inject this standard mixture prior to beginning the initial calibrationor calibration verification.
CAUTION: Several analytes, including aldrin, may be observed in the injection just following this system priming because of carry-over. Always run anacceptable blank prior to running any standards or samples.
Calibration factors When external standard calibration is employed, calculate the calibration factor for each analyte at each concentration, the mean calibration factor, and the relative standarddeviation (RSD) of the calibration factors, using the formulae below. If internal standardcalibration is employed, refer to Method 8000 for the calculation of response factors.
Calculate the calibration factor for each analyte at each concentration as: Peak Area (or Height) of the Compound in the Standard Mass of the Compound Injected (in nanograms) Calculate the mean calibration factor for each analyte as: where n is the number of standards analyzed.
Calculate the standard deviation (SD) and the RSD of the calibration factors for each analyte as: If the RSD for each analyte is < 20%, then the response of the instrument isconsidered linear and the mean calibration factor may be used to quantitatesample results. If the RSD is greater than 20%, the analyst should consult Method8000 for other calibration options, which may include either a linear calibration notthrough the origin or a non-linear calibration model (e.g., a polynomial equation).
Retention time windows Absolute retention times are generally used for compound identification. When absolute retention times are used, retention time windows are crucial to the identificationof target compounds, and should be established by one of the approaches described inMethod 8000. Retention time windows are established to compensate for minor shifts inabsolute retention times as a result of sample loadings and normal chromatographicvariability. The width of the retention time window should be carefully established tominimize the occurrence of both false positive and false negative results. Tight retentiontime windows may result in false negatives and/or may cause unnecessary reanalysis ofsamples when surrogates or spiked compounds are erroneously not identified. Overlywide retention time windows may result in false positive results that cannot be confirmedupon further analysis. Analysts should consult Method 8000 for the details of establishingretention time windows. Other approaches to compound identification may be employed,provided that the analyst can demonstrate and document that the approaches areappropriate for the intended application.
Before establishing the retention time windows, make sure that the gas chromatographic system is operating within optimum conditions.
The widths of the retention time windows are defined as described in Method 8000. However, the experience of the analyst should weighheavily during the interpretation of the chromatograms.
Gas chromatographic analysis of sample extracts The same GC operating conditions used for the initial calibration must be employed for the analysis of samples.
Verify calibration at least once each 12-hr shift by injecting calibration verification standards prior to conducting any sample analyses. Analysts should alternatethe use of high and low concentration mixtures of single-component analytes and multi-component analytes for calibration verification. A calibration standard must also beinjected at intervals of not less than once every twenty samples (after every 10 samples isrecommended to minimize the number of samples requiring re-injection when QC limitsare exceeded) and at the end of the analysis sequence. See Sec. 9.3 for additionalguidance on the frequency of the standard injections.
The calibration factor for each analyte should not exceed a ±20 percent difference from the mean calibration factor calculated for the initialcalibration. If a calibration approach other than the RSD method has beenemployed for the initial calibration (e.g., a linear model not through the origin, anon-linear calibration model, etc.), consult Method 8000 for the specific details ofcalibration verification.
If the calibration does not meet the ±20% limit on the basis of each compound, check the instrument operating conditions, and if necessary,restore them to the original settings, and inject another aliquot of the calibrationverification standard. If the response for the analyte is still not within ±20%, then anew initial calibration must be prepared. The effects of a failing calibrationverification standard on sample results are discussed in Sec. 11.5.7.
Compare the retention time of each analyte in the calibration standard with the absolute retention time windows established in Sec. 11.4.6. Each analyte in eachsubsequent standard run during the 12-hr period must fall within its respective retentiontime window. If not, the gas chromatographic system must either be adjusted so that asecond analysis of the standard does result in all analytes falling within their retention timewindows, or a new initial calibration must be performed and new retention time windowsestablished. As noted in Sec. 11.4.6, other approaches to compound identification may beemployed, provided that the analyst can demonstrate and document that the approachesare appropriate for the intended application.
Inject a measured aliquot of the concentrated sample extract. A 2-µL aliquot is suggested, however, the same injection volume should be used for both thecalibration standards and the sample extracts, unless the analyst can demonstrateacceptable performance using different volumes or conditions. Record the volumeinjected and the resulting peak size in area units.
Tentative identification of an analyte (either single-component or multi-component) occurs when a peak from a sample extract falls within the daily retention time window. Confirmation is necessary when the sample composition is not well characterized. Confirmatory techniques such as gas chromatography with a dissimilar column or a massspectrometer should be used. See Method 8000 for information on confirmation oftentative identifications. See Sec. 11.7 of this method for information on the use of GC/MSas a confirmation technique.
When results are confirmed using a second GC column of dissimilar stationary phase, the analyst should check the agreement between the quantitative results on bothcolumns once the identification has been confirmed. See Method 8000 for a discussion ofsuch a comparison and appropriate data reporting approaches.
When using the external calibration procedure (Method 8000), determine the quantity of each component peak in the sample chromatogram which corresponds tothe compounds used for calibration purposes, as follows. The appropriate selection of abaseline from which the peak area or height can be determined is necessary for properquantitation.
For aqueous samples: Concentration (µg/L) ' A = Area (or height) of the peak for the analyte in the sample.
V = Total volume of the concentrated extract (µL).
D = Dilution factor, if the sample or extract was diluted prior to analysis. If no dilution was made, D = 1. The dilution factor is always dimensionless.
& = Mean calibration factor from the initial calibration (area/ng).
V = Volume of the extract injected (µL). The injection volume for samples and calibration standards should be the same, unless the analyst candemonstrate acceptable performance using different volumes orconditions. V = Volume of the aqueous sample extracted in mL. If units of liters are used for this term, multiply the results by 1000. Using the units given here for these terms will result in a concentration in units ofng/mL, which is equivalent to µg/L.
For non-aqueous samples: Concentration (µg/kg) ' &, and V are the same as for aqueous samples, and W = Weight of sample extracted (g). The wet weight or dry weight may be used, depending upon the specific application of the data. If units ofkilograms are used for this term, multiply the results by 1000.
Using the units given here for these terms will result in a concentration in units ofng/g, which is equivalent to µg/kg.
See Method 8000 for the equation used for internal standard If the responses exceed the calibration range of the system, dilute the extract and reanalyze. Peak height measurements are recommended over peak area integration when overlapping peaks cause errors in areaintegration.
If partially overlapping or coeluting peaks are found, change GC columns or try GC/MS quantitation (see Sec. 9.0 of this method and seeMethod 8270).
Each sample analysis employing external standard calibration must be bracketed with an acceptable initial calibration, calibration verification standards (each 12-hr analytical shift), or calibration standards interspersed within the samples. The resultsfrom these bracketing standards must meet the calibration verification criteria in Sec.
11.5.2.
Although analysis of a single mid-concentration standard (standard mixture or multi-component analyte) will satisfy the minimum requirements, analysts are urged to usedifferent calibration verification standards during organochlorine pesticide analyses. Also,multi-level standards (mixtures or multi-component analytes) are highly recommended toensure that the detector response remains stable for all the analytes over the calibrationrange.
When a calibration verification standard fails to meet the QC criteria, all samples that were injected after the last standard that last met the QC criteria must be evaluated toprevent misquantitations and possible false negative results, and reinjection of the sampleextracts may be necessary. More frequent analyses of standards will minimize thenumber of sample extracts that would have to be reinjected if the QC limits are violated forthe standard analysis.
However, if the standard analyzed after a group of samples exhibits a response for an analyte that is above the acceptance limit, i.e., >20%, and the analyte was not detectedin the specific samples analyzed during the analytical shift, then the extracts for thosesamples do not need to be reanalyzed, as the verification standard has demonstrated thatthe analyte would have been detected were it present. In contrast, if an analyte above theQC limits was detected in a sample extract, then reinjection is necessary to ensureaccurate quantitation. If an analyte was not detected in the sample and the standardresponse is more than 20% below the initial calibration response, then reinjection isnecessary to ensure that the detector response has not deteriorated to the point that theanalyte would not have been detected even though it was present (i.e., a false negativeresult).
Sample injections may continue for as long as the calibration verification standards and standards interspersed with the samples meet instrument QCrequirements. It is recommended that standards be analyzed after every 10 samples(required after every 20 samples and at the end of a set) to minimize the number ofsamples that must be re-injected when the standards fail the QC limits. The sequenceends when the set of samples has been injected or when qualitative and/or quantitativeQC criteria are exceeded.
The use of internal standard calibration techniques does not require that all sample results be bracketed with calibration verification standards. However, wheninternal standard calibration is used, the retention times of the internal standards and thearea responses of the internal standards should be checked for each analysis. Retentiontime shifts of >30 sec from the retention time of the most recent calibration standardand/or changes in internal standard areas of more than -50 to +100% are cause forconcern and must be investigated.
11.5.10 If the peak response is less than 2.5 times the baseline noise level, the validity of the quantitative result may be questionable. Consult with the source of thesample to determine whether further concentration of the sample is warranted.
11.5.11 Use the calibration standards analyzed during the sequence to evaluate retention time stability. Each subsequent injection of a standard during the 12-hranalytical shift (i.e., those standards injected every 20 samples, or more frequently) mustbe checked against the retention time windows. If any of these subsequent standards falloutside their absolute retention time windows, the GC system is out of control. Determinethe cause of the problem and correct it. If the problem cannot be corrected, a new initialcalibration must be performed.
11.5.12 The identification of mixtures (i.e., chlordane and toxaphene) is not based on a single peak, but rather on the characteristic peaks that comprise the "fingerprint" ofthe mixture, using both the retention times and shapes of the indicator peaks. Quantitation is based on the areas of the characteristic peaks as compared to the areas ofthe corresponding peaks at the same retention times in the calibration standard, usingeither internal or external calibration procedures. See Method 8000 for information onconfirmation of tentative identifications. See Sec. 11.7 of this procedure for information onthe use of GC/MS as a confirmation technique.
11.5.13 If compound identification or quantitation is precluded due to interference (e.g., broad, rounded peaks or ill-defined baselines), cleanup of the extract or replacementof the capillary column or detector is warranted. Rerun the sample on another instrumentto determine if the problem results from analytical hardware or the sample matrix. Refer toMethod 3600 for the procedures to be followed in sample cleanup.
Quantitation of multi-component analytes -- Multi-component analytes present problems in measurement. Suggestions are offered in the following sections for handlingtoxaphene, Strobane, chlordane, BHC, and DDT.
Toxaphene and Strobane -- Toxaphene is manufactured by the chlorination of camphenes, whereas Strobane results from the chlorination of a mixture ofcamphenes and pinenes. Quantitation of toxaphene or Strobane is difficult, butreasonable accuracy can be obtained. To calculate toxaphene from GC/ECD results: 11.6.1.1. Adjust the sample size so that the major toxaphene peaks are 10 - 70% of full-scale deflection (FSD).
Inject a toxaphene standard that is estimated to be within ±10 ng of the sample amount.
Quantitate toxaphene using the total area of the toxaphene pattern or using 4 to 6 major peaks. While toxaphene contains a large number of compounds that will produce well resolved peaks in a GC/ECDchromatogram, it also contains many other components that are notchromatographically resolved. This unresolved complex mixture resultsin the "hump" in the chromatogram that is characteristic of this mixture. Although the resolved peaks are important for the identification of themixture, the area of the unresolved complex mixture contributes asignificant portion of the area of the total response.
To measure total area, construct the baseline of toxaphene in the sample chromatogram between the retention times ofthe first and last eluting toxaphene components in the standard. In orderto use the total area approach, the pattern in the sample chromatogrammust be compared to that of the standard to ensure that all of the majorcomponents in the standard are present in the sample. Otherwise, thesample concentration may be significantly underestimated.
Toxaphene may also be quantitated on the basis of 4 to 6 major peaks. A collaborative study of a series of toxapheneresidues evaluated several approaches to quantitation of this compound,including the use of the total area of the peaks in the toxaphenechromatogram and the use of a subset of 4 to 6 peaks. That studyindicated that the use of 4 to 6 peaks provides results that agree well withthe total peak area approach and may avoid difficulties wheninterferences with toxaphene peaks are present in the early portion of thechromatogram from compounds such as DDT. Whichever approach isemployed should be documented and available to the data user, ifnecessary.
When toxaphene is determined using the 4 to 6 peaks approach, the analyst must take care to evaluate the relative areasof the peaks chosen in the sample and standard chromatograms. It ishighly unlikely that the peaks will match exactly, but the analyst shouldnot employ peaks from the sample chromatogram whose relative sizes orareas appear to be disproportionally larger or smaller in the samplecompared to the standard.
The heights or areas of the 4 to 6 peaks that are selected should be summed together and used to determine thetoxaphene concentration. Alternatively, use each peak in the standard tocalculate a calibration factor for that peak, using the total mass oftoxaphene in the standard. These calibration factors are then used tocalculate the concentration of each corresponding peak in the samplechromatogram and the 4 to 6 resulting concentrations are averaged toprovide the final result for the sample.
Chlordane -- Technical chlordane is a mixture of at least 11 major components and 30 or more minor components that have been used to prepare specificpesticide formulations. The nomenclature of the various forms of chlordane has been thesubject of some confusion in both Agency methods and the open literature for some time. The CAS number for technical chlordane is properly given as 12789-03-6. The two mostprevalent major components of technical chlordane are cis-chlordane, CAS number 5103-71-9 and trans-chlordane, CAS number 5103-74-2. The structure represented by trans-chlordane has on occasion been mistakenly referred to by the name gamma-chlordane,and a separate CAS number of 5566-34-7 has been assigned by CAS to that designation. For the purposes of the RCRA program, the name gamma-chlordane is not generallyused, and when reporting technical chlordane it is important to distinguish the differencebetween the trans and gamma isomers.
The exact percentages of cis-chlordane and trans-chlordane in the technical material are not completely defined, and are not consistent from batch to batch. Moreover, changes may occur when the technical material is used to prepare specificpesticide formulations. The approach used for evaluating and reporting chlordane results will often depend on the end use of the results and the analyst's skill in interpreting thismulticomponent pesticide residue. The following sections discuss three specific options: reporting technical chlordane (CAS number 12789-03-6), reporting chlordane (nototherwise specified, or n.o.s., CAS number 57-74-9), and reporting the individualchlordane components that can be identified under their individual CAS numbers.
When the GC pattern of the residue resembles that of technical chlordane, the analyst may quantitate chlordane residues by comparingthe total area of the chlordane chromatogram using three to five major peaks or thetotal area. If the heptachlor epoxide peak is relatively small, include it as part ofthe total chlordane area for calculation of the residue. If heptachlor and/orheptachlor epoxide are much out of proportion, calculate these separately andsubtract their areas from the total area to give a corrected chlordane area.
NOTE: Octachloro epoxide, a metabolite of chlordane, can easily be mistaken for heptachlor epoxide on a nonpolar GC column.
To measure the total area of the chlordane chromatogram, inject an amount of a technical chlordane standard which will produce a chromatogram inwhich the major peaks are approximately the same size as those in the samplechromatograms. Construct the baseline of technical chlordane in the standardchromatogram between the retention times of the first and last eluting chlordanecomponents. Use this area and the mass of technical chlordane in the standard tocalculate a calibration factor. Construct a similar baseline in the samplechromatogram, measure the area, and use the calibration factor to calculate theconcentration in the sample.
The GC pattern of a chlordane residue in a sample may differ considerably from that of the technical chlordane standard. In such instances, itmay not be practical to relate a sample chromatogram back to the pesticide activeingredient technical chlordane. Therefore, depending on the objectives of theanalysis, the analyst may choose to report the sum of all the identifiable chlordanecomponents as "chlordane (n.o.s.)" under the CAS number 57-74-9.
The third option is to quantitate the peaks of cis-chlordane, trans-chlordane, and heptachlor separately against the appropriate referencematerials, and report these individual components under their respective CASnumbers.
To measure the total area of the chlordane chromatogram, inject an amount of a technical chlordane standard which will produce achromatogram in which the major peaks are approximately the same size as thosein the sample chromatograms.
Hexachlorocyclohexane -- Hexachlorocyclohexane is also known as BHC, from the former name, benzene hexachloride. Technical grade BHC is a cream-colored amorphous solid with a very characteristic musty odor. It consists of a mixture ofsix chemically distinct isomers and one or more heptachlorocyclohexanes andoctachlorocyclohexanes. Commercial BHC preparations may show a wide variance in thepercentage of individual isomers present. Quantitate each isomer (α, β, γ, and δ)separately against a standard of the respective pure isomer.
DDT -- Technical DDT consists primarily of a mixture of 4,4'-DDT (approximately 75%) and 2,4'-DDT (approximately 25%). As DDT weathers, 4,4'-DDE, 2,4'-DDE, 4,4'-DDD, and 2,4'-DDD are formed. Since the 4,4'-isomers of DDT, DDE, andDDD predominate in the environment, and these are the isomers normally regulated byEPA, sample extracts should be quantitated against standards of the respective pureisomers of 4,4'-DDT, 4,4'-DDE, and 4,4'-DDD.
GC/MS confirmation GC/MS confirmation may be used in conjunction with either single-column or dual-column analysis if the concentration is sufficient for detection by GC/MS.
Full-scan GC/MS will normally require a concentration of approximately 10 ng/µL in the final extract for each single-component compound. Ion trap or selected ionmonitoring will normally require a concentration of approximately 1 ng/µL.
The GC/MS must be calibrated for the specific target pesticides when it is used for quantitative analysis. If GC/MS is used only for confirmation of the identificationof the target analytes, then the analyst must demonstrate that those pesticides identifiedby GC/ECD can be confirmed by GC/MS. This demonstration may be accomplished byanalyzing a single-point standard containing the analytes of interest at or below theconcentrations reported in the GC/ECD analysis.
GC/MS is not recommended for confirmation when concentrations are below 1 ng/µL in the extract, unless a more sensitive mass spectrometer is employed.
GC/MS confirmation should be accomplished by analyzing the same extract that is used for GC/ECD analysis and the extract of the associated method blank.
If a base/neutral/acid extraction of an aqueous sample was performed for an analysis of semivolatile organics (e.g., Method 8270), then that extract and theassociated blank may be used for GC/MS confirmation if the surrogates and internalstandards do not interfere and if it is demonstrated that the analyte is stable duringacid/base partitioning. However, if the compounds are not detected in thebase/neutral/acid extract, then GC/MS analysis of the pesticide extract should beperformed.
GC/AED confirmation by Method 8085 may be used in conjunction with either single-column or dual-column analysis if the concentration is sufficient for detection by GC/AED.
Chromatographic system maintenance as corrective action When system performance does not meet the established QC requirements, corrective action is required, and may include one or more of the activities described below.
Splitter connections For dual-columns which are connected using a press-fit Y-shaped glass splitter or a Y-shaped fused-silica connector, clean and deactivate the splitter port insert or replacewith a cleaned and deactivated splitter. Break off the first few centimeters (up to 30 cm) ofthe injection port side of the column. Remove the columns and solvent backflushaccording to the manufacturer's instructions. If these procedures fail to eliminate thedegradation problem, it may be necessary to deactivate the metal injector body and/orreplace the columns. GC injector ports The injector ports can be of critical concern, especially in the analysis of DDT and endrin. Injectors that are contaminated, chemically active, or too hot can cause thedegradation ("breakdown") of the analytes. Endrin and DDT break down to endrinaldehyde, endrin ketone, DDD, or DDE. When such breakdown is observed, clean anddeactivate the injector port, break off at least 30 cm of the column and remount it. Checkthe injector temperature and lower it to 205 EC, if necessary. Endrin and DDT breakdown is less of a problem when ambient on-column injectors are used.
Metal injector body Turn off the oven and remove the analytical columns when the oven has cooled. Remove the glass injection port insert (instruments with on-column injection). Lower theinjection port temperature to room temperature. Inspect the injection port and remove anynoticeable foreign material.
Place a beaker beneath the injector port inside the oven. Using a wash bottle, serially rinse the entire inside of the injector port with acetoneand then toluene, catching the rinsate in the beaker.
Prepare a solution of a deactivating agent (Sylon-CT or equivalent), following the manufacturer's directions. After all metal surfaces insidethe injector body have been thoroughly coated with the deactivation solution, rinsethe injector body with toluene, methanol, acetone, then hexane. Reassemble theinjector and replace the columns.
Rinse the column with several column volumes of an appropriate solvent. Both polar and nonpolar solvents are recommended. Depending on the nature of the sampleresidues expected, the first rinse might be water, followed by methanol and acetone. Methylene chloride is a good final rinse and in some cases may be the only solventnecessary. Fill the column with methylene chloride and allow it to stand flooded overnightto allow materials within the stationary phase to migrate into the solvent. Afterwards, flushthe column with fresh methylene chloride, drain the column, and dry it at room temperaturewith a stream of ultrapure nitrogen.
12.0 DATA ANALYSIS AND CALCULATIONS See Secs. 11.4 through 11.6 and Method 8000 for information on data analysis and 13.0 METHOD PERFORMANCE Performance data and related information are provided in SW-846 methods only as examples and guidance. The data do not represent required performance criteria for users ofthe methods. Instead, performance criteria should be developed on a project-specific basis,and the laboratory should establish in-house QC performance criteria for the application of thismethod. These performance data are not intended to be and must not be used as absolute QCacceptance criteria for purposes of laboratory accreditation.
The chromatographic separations in this method were tested in a single laboratory by using clean hexane and liquid and solid waste extracts that were spiked with the testcompounds at three concentrations. Single-operator precision, overall precision, and methodaccuracy were found to be related to the concentration of the compound and the type of matrix.
The levels of accuracy and precision that can be achieved with this method depend on the sample matrix, sample preparation technique, optional cleanup techniques, andcalibration procedures used.
Tables 8 and 9 contain precision (as % RSD) and accuracy (as % recovery) data generated for sewage sludge and dichloroethane stillbottoms. Table 10 contains recovery datafor a clay soil, taken from Reference 10. The spiking concentration for the clay soil was 500µg/kg. The spiking solution was mixed into the soil and then immediately transferred to theextraction device and immersed in the extraction solvent. The spiked sample was thenextracted by Method 3541 (Automated Soxhlet). The data represent a single determination. Analysis was by capillary column gas chromatography/electron capture detector. These dataare provided for guidance purposes only.
Table 11 contains single-laboratory precision and accuracy data for solid-phase extraction of TCLP buffer solutions spiked at two levels and extracted using Method 3535. These data are provided for guidance purposes only.
Table 12 contains multiple-laboratory data for solid-phase extraction of spiked TCLP soil leachates extracted using Method 3535. These data are provided for guidancepurposes only.
Table 13 contains single-laboratory data on groundwater and wastewater samples extracted by solid-phase extraction, using Method 3535. These data are provided for guidancepurposes only.
Tables 14 and 15 contain single-laboratory performance data using supercritical fluid extraction (Method 3562). Samples were analyzed by GC/ELCD. The method wasperformed using a variable restrictor and solid trapping material (octadecyl silane [ODS]). Threedifferent soil samples were spiked at 5 and 250 µg/kg. Soil 1 (Delphi) is described as loamysand, with 2.4% clay, 94% sand, 0.9% organic matter, 3.4% silt, and 0.1% moisture. Soil 2(McCarthy) is described as sandy-loam, with 11% clay, 56% sand, 22% organic matter, 33%silt, and 8.7% moisture. Soil 3 (Auburn) is described as clay loam, with 32% clay, 21% sand,5.4% organic matter, 46% silt, and 2.2% moisture. Seven replicate extractions were made ofeach soil at the two concentrations. These data are provided for guidance purposes only.
Tables 16 through 18 contain single-laboratory accuracy data for chlorinated pesticides extracted by pressurized fluid extraction (Method 3545) from clay, loam, and sandsamples spiked by a commercial supplier at three certified concentrations (low, medium, andhigh). Samples of 10 to14 g were extracted with hexane:acetone (1:1), at 100 EC and 2000 psi, using a 5-min heating time and a 5-min static extraction. Extract volumes were 13 to 15 mL,and were adjusted prior to GC/EC analysis to match the linear range of the instrumentation. The data are taken from Reference 14, where the PFE results were presented as the percent ofthe results from an automated Soxhlet (Method 3541) extraction, which were in turn reported asa percent of the certified values. These data are provided for guidance purposes only.
13.10 Tables 19 and 20 contain single-laboratory accuracy data for chlorinated pesticides extracted from natural soils, glass-fiber, and sand matrices, using microwave extraction (Method3546). Concentrations of each target analyte ranged from between 0.5 to 10 µg/g. Four real-world split samples contaminated with pesticides and creosotes were also used (obtained from US EPA ERT, Edison, NJ). The latter were extracted by an independent laboratory usingstandard Soxhlet procedures and results compared to those obtained with this procedure. Allsamples were extracted using 1:1 hexane:acetone. Extracts were analyzed by Method 8081. Method blanks and five spiked replicates were included. Work was also carried out to assessthe level of degradation of thermally labile pesticides and it was found that no significantdegradation takes place under the procedure described herein. The data are taken fromReference 15. These data are provided for guidance purposes only.
14.0 POLLUTION PREVENTION Pollution prevention encompasses any technique that reduces or eliminates the quantity and/or toxicity of waste at the point of generation. Numerous opportunities for pollutionprevention exist in laboratory operations. The EPA has established a preferred hierarchy ofenvironmental management techniques that places pollution prevention as the managementoption of first choice. Whenever feasible, laboratory personnel should use pollution preventiontechniques to address their waste generation. When wastes cannot be feasibly reduced at thesource, the Agency recommends recycling as the next best option.
For information about pollution prevention that may be applicable to laboratories and research institutions consult Less is Better: Laboratory Chemical management for WasteReduction available from the American Chemical Society, Department of Government Relationsand Science Policy, 1155 16th Street, NW, Washington, DC, 20036, (202) 872-4477),http://www.acs.org.
15.0 WASTE MANAGEMENT The Environmental Protection Agency requires that laboratory waste management practices be conducted consistent with all applicable rules and regulations. The Agency urgeslaboratories to protect the air, water, and land by minimizing and controlling all releases fromhoods and bench operations, complying with the letter and spirit of any sewer discharge permitsand regulations, and by complying with all solid and hazardous waste regulations, particularlythe hazardous waste identification rules and land disposal restrictions. For further informationon waste management, consult The Waste Management Manual for Laboratory Personnelavailable from the American Chemical Society at the address listed in Sec. 14.2.
V. Lopez-Avila, E. Baldin, J. Benedicto, J. Milanes, W. F. Beckert, "Application of Open-Tubular Columns to SW-846 GC Methods," report to the U.S. Environmental ProtectionAgency, Contract 68-03-3511, Mid-Pacific Environmental Laboratory, Mountain View, CA,1990. "Development and Application of Test Procedures for Specific Organic Toxic Substancesin Wastewaters," Category 10, Pesticides and PCB Report for the U.S. EnvironmentalProtection Agency, Contract 68-03-2606.
D. F. Goerlitz, L. M. Law, "Removal of Elemental Sulfur Interferences from SedimentExtracts for Pesticide Analysis," Bull. Environ. Contam. Toxicol., 6, 9, 1971.
S. Jensen, L. Renberg, L. Reutergardth, "Residue Analysis of Sediment and SewageSludge for Organochlorines in the Presence of Elemental Sulfur," Anal. Chem., 49, 316-318, 1977.
R. H. Wise, D. F. Bishop, R. T. Williams, B. M. Austern, B.M., "Gel PermeationChromatography in the GC/MS Analysis of Organics in Sludges," U.S. EnvironmentalProtection Agency, Cincinnati, OH.
H. B. Pionke, G. Chesters, D.E. Armstrong, "Extraction of Chlorinated HydrocarbonInsecticides from Soil," Agron. J., 60, 289, 1968.
J. A. Burke, P. A. Mills, D.C. Bostwick, "Experiments with Evaporation of Solutions ofChlorinated Pesticides," J. Assoc. Off. Anal. Chem., 49, 999, 1966.
J. A. Glazer, et al., "Trace Analyses for Wastewaters," Environ. Sci. and Technol., 15,1426 , 1981.
P. J. Marsden, "Performance Data for SW-846 Methods 8270, 8081, and 8141," U.S.
Environmental Protection Agency, EMSL-Las Vegas, EPA/600/4-90/015.
10. V. Lopez-Avila (Beckert, W., Project Officer), "Development of a Soxtec Extraction Procedure for Extracting Organic Compounds from Soils and Sediments," EPA600/X-91/140, US Environmental Protection Agency, Environmental Monitoring SystemsLaboratory, Las Vegas, NV, October 1991.
11. C. Markell, "Solid-Phase Extraction of TCLP Leachates," Proceedings of the Tenth Annual Waste Testing and Quality Assurance Symposium, Arlington, VA, July, 1994.
12. D. Bennett, B. Lesnik, S. M. Lee, "Supercritical Fluid Extraction of Organochlorine Pesticide Residues from Soils," Proceedings of the Tenth Annual Waste Testing andQuality Assurance Symposium, Arlington, VA, July, 1994.
13. C. Markell, "3M Data Submission to EPA," letter to B. Lesnik, June 27, 1995.
14. B. Richter, J. Ezzell, and D. Felix, "Single Laboratory Method Validation Report -- Extraction of Organophosphorus Pesticides, Herbicides and Polychlorinated BiphenylsUsing Accelerated Solvent Extraction (ASE) with Analytical Validation by GC/NPD andGC/ECD," Dionex, Salt Lake City, UT, Document 101124, December 2, 1994.
15. K. Li, J. M. R. Bélanger, M. P. Llompart, R. D. Turpin, R. Singhvi, and J. R. J. Paré. Evaluation of rapid solid sample extraction using the microwave-assisted process (MAPTM)under closed-vessel conditions. Spectros. Int. J. 13 (1), 1-14 (1997).
17.0 TABLES, DIAGRAMS, FLOW CHARTS, AND VALIDATION DATA The following pages contain the tables and figures referenced by this method.
EXAMPLE GAS CHROMATOGRAPHIC RETENTION TIMES FOR THE ORGANOCHLORINE PESTICIDES USING WIDE-BORE CAPILLARY COLUMNS SINGLE-COLUMN METHOD OF ANALYSIS Retention Time (min) Endosulfan sulfate Heptachlor epoxide MR = Multiple response compound.
a See Table 4 for the GC operating conditions used for these analyses.
All data are provided for illustrative purposes only. Each laboratory must determineretention times and retention time windows for their specific application of themethod.
EXAMPLE GAS CHROMATOGRAPHIC RETENTION TIMES FOR THE ORGANOCHLORINE PESTICIDES USING NARROW-BORE CAPILLARY COLUMNS SINGLE-COLUMN METHOD OF ANALYSIS Retention Time (min) Endosulfan sulfate Heptachlor epoxide NA = Data not available.
MR = Multiple response compound.
a See Table 3 for the GC operating conditions.
All data are provided for illustrative purposes only. Each laboratory must determineretention times and retention time windows for their specific application of themethod.
SUGGESTED GC OPERATING CONDITIONS FOR ORGANOCHLORINE COMPOUNDS SINGLE-COLUMN ANALYSIS USING NARROW-BORE COLUMNS Column 1 -- 30-m x 0.25 or 0.32-mm ID fused-silica capillary column chemically bonded withSE-54 (DB-5 or equivalent), 1-µm film thickness.
Carrier gas pressure Injector temperature Detector temperature Initial temperature 100 EC, hold 2 min Temperature program 100 EC to 160 EC at 15 EC/min, followed by 160 EC to 270 EC at 5 Final temperature Column 2 -- 30-m x 0.25-mm ID fused-silica capillary column chemically bonded with 35percent phenyl methylpolysiloxane (DB-608, SPB-608, or equivalent), 1-µm film thickness.
Carrier gas pressure Injector temperature Detector temperature Initial temperature 160 EC, hold 2 min Temperature program 160 EC to 290 EC at 5 EC/min Final temperature 290 EC, hold 1 min SUGGESTED GC OPERATING CONDITIONS FOR ORGANOCHLORINE COMPOUNDS SINGLE-COLUMN ANALYSIS USING WIDE-BORE COLUMNS Column 1 -- 30-m x 0.53-mm ID fused-silica capillary column chemically bonded with 35percent phenyl methylpolysiloxane (DB-608, SPB-608, RTx-35, or equivalent), 0.5-µm or0.83-µm film thickness.
Column 2 -- 30-m x 0.53-mm ID fused-silica capillary column chemically bonded with 50percent phenyl methylpolysiloxane (DB-1701, or equivalent), 1.0-µm film thickness.
Both Column 1 and Column 2 use the same GC operating conditions.
Carrier gas flow rate argon/methane (P-5 or P-10) or nitrogen Makeup gas flow rate Injector temperature Detector temperature Initial temperature 150 EC, hold 0.5 min Temperature program 150 EC to 270 EC at 5 EC/min Final temperature 270 EC, hold 10 min Column 3 -- 30-m x 0.53-mm ID fused-silica capillary column chemically bonded with SE-54 (DB-5, SPB-5, RTx-5, or equivalent), 1.5-µm film thickness.
Carrier gas flow rate argon/methane (P-5 or P-10) or nitrogen Makeup gas flow rate Injector temperature Detector temperature Initial temperature 140 EC, hold 2 min Temperature program 140 EC to 240 EC at 10 EC/min, hold 5 min at 240 EC, 240 EC to 265 EC at 5 EC/min Final temperature 265 EC, hold 18 min EXAMPLE RETENTION TIMES OF THE ORGANOCHLORINE PESTICIDESa DUAL-COLUMN METHOD OF ANALYSIS Heptachlor epoxide Endosulfan sulfate See Table 6 for the GC operating conditions.
Not detected at 2 ng per injection.
All data are provided for illustrative purposes only. Each laboratory must determine retentiontimes and retention time windows for their specific application of the method.
SUGGESTED GC OPERATING CONDITIONS FOR ORGANOCHLORINE PESTICIDES FOR DUAL-COLUMN METHOD OF ANALYSIS LOW TEMPERATURE, THIN FILM DB-1701 or equivalent30-m x 0.53-mm ID1.0-µm film thickness DB-5 or equivalent30-m x 0.53-mm ID0.83-µm film thickness Carrier gas flow rate Makeup gas flow rate Injector temperature Detector temperature Initial temperature 140 EC, hold 2 min Temperature program 140 EC to 270 EC at 2.8 EC/min Final temperature 270 EC, hold 1 min SUGGESTED GC OPERATING CONDITIONS FOR ORGANOCHLORINE PESTICIDES FOR THE DUAL-COLUMN METHOD OF ANALYSIS HIGH TEMPERATURE, THICK FILM DB-1701 or equivalent30-m x 0.53-mm ID1.0-µm film thickness DB-5 or equivalent30-m x 0.53-mm ID1.5-µm film thickness Carrier gas flow rate: Makeup gas flow rate: Injector temperature: Detector temperature: Initial temperature: 150 EC, hold 0.5 min Temperature program: 150 EC to 190 EC at 12 EC/min, hold 2 min190 EC to 275 Final temperature 275 EC, hold 10 min EXAMPLE ANALYTE RECOVERY FROM SEWAGE SLUDGE Ultrasonic Extraction 4-Bromodiphenyl ether Heptachlor epoxide nd = Not detectedConcentration spiked in the sample: 500-1000 ng/g, analyses of three replicates.
Soxhlet extraction by Method 3540 with methylene chloride.
Ultrasonic extraction by Method 3550 with methylene chloride/acetone (1:1).
Cleanup by Method 3640.
GC column: DB-608, 30-m x 0.53-mm ID.
These data are provided for guidance purposes only.
EXAMPLE ANALYTE RECOVERY FROM DICHLOROETHANE STILLBOTTOMS Ultrasonic Extraction 4-Bromodiphenyl ether Heptachlor epoxide Concentration spiked in the sample: 500-1000 ng/g, three replicates analyses.
Soxhlet extraction by Method 3540 with methylene chloride.
Ultrasonic extraction by Method 3550 with methylene chloride/acetone (1:1).
Cleanup by Method 3640.
GC column: DB-608, 30-m x 0.53-mm ID.
These data are provided for guidance purposes only.
EXAMPLE SINGLE-LABORATORY ACCURACY DATA FOR THE EXTRACTION OF ORGANOCHLORINE PESTICIDES FROM SPIKED CLAY SOIL BY METHOD 3541 (AUTOMATED SOXHLET)a Heptachlor epoxide a The operating conditions for the automated Soxhlet were: Immersion time 45 minExtraction time 45 min10-g sample sizeExtraction solvent 1:1 acetone/hexaneNo equilibration time following spiking.
ND = Not able to determine because of interference.
All compounds were spiked at 500 µg/kg.
Data are taken from Reference 10.
These data are provided for guidance purposes only.
EXAMPLE SINGLE-LABORATORY RECOVERY DATA FOR SOLID-PHASE EXTRACTION OF ORGANOCHLORINE PESTICIDES FROM TCLP BUFFERS SPIKED AT TWO LEVELS Buffer 1 (pH = 2.886) Buffer 2 (pH = 4.937) Heptachlor epoxide Heptachlor epoxide Results were from seven replicate spiked buffer samples, except where noted with *, whichindicates that only three replicates were analyzed.
These data are provided for guidance purposes only.
EXAMPLE RECOVERY DATA FROM THREE LABORATORIES FOR SOLID-PHASE EXTRACTION OF ORGANOCHLORINE PESTICIDES FROM SPIKED TCLP LEACHATES FROM SOIL SAMPLES Buffer 1 pH = 2.886 Heptachlor epoxide Buffer 2 pH = 4.937 Heptachlor epoxide * 250-mL aliquots of leachate were spiked by Labs 2 and 3 at the levels shown. Lab 1 spiked at one-half these levels.
These data are provided for guidance purposes only.
EXAMPLE SINGLE-LABORATORY ACCURACY AND PRECISION DATA FOR SOLID-PHASE EXTRACTION BY METHOD 35351 Heptachlor epoxide 1All results determined from seven replicates of each sample type. Two spiking levels were used. "Low" samples were spiked at 5-10 µg/L for each analyte, while"high" samples were spiked at 250 - 500 µg/L.
These data are provided for guidance purposes only.
EXAMPLE RECOVERY (BIAS) OF ORGANOCHLORINE PESTICIDES USING SFE METHOD 3562 (Seven replicates) Heptachlor epoxide Matrix Mean Recovery a Delphi: Loamy sand soilb McCarthy: Sandy loamy-organic rich soilc Auburn: Clay-loamy soilThese data are provided for guidance purposes only.
EXAMPLE RELATIVE STANDARD DEVIATION (PRECISION) OF ORGANOCHLORINE PESTICIDES USING SFE METHOD 3562 (Seven replicates) Heptachlor epoxide Matrix Mean Recovery a Delphi: Loamy sand soilb McCarthy: Sandy loamy-organic rich soilc Auburn: Clay-loamy soilThese data are provided for guidance purposes only.
EXAMPLE SINGLE-LABORATORY ORGANOCHLORINE PESTICIDES DATA FROM THREE SOIL MATRICES SPIKED AT 5 TO 10 PPB AND EXTRACTED USING METHOD 3545 (PRESSURIZED FLUID EXTRACTION) PFE Recovery and Precision Endosulfan sulfate Heptachlor epoxide Seven replicate extractions were performed using 14-g samples of spiked soil from a commercialsupplier. Hexane:acetone (1:1) was used as the extraction solvent, at 100 EC and 2000 psi, using a 5- min heating time and a 5-min static extraction. Data are adapted from Reference 14.
These data are provided for guidance purposes only.
EXAMPLE SINGLE-LABORATORY ORGANOCHLORINE PESTICIDES DATA FROM THREE SOIL MATRICES SPIKED AT 50 TO 100 PPB AND EXTRACTED USING METHOD 3545 (PRESSURIZED FLUID EXTRACTION) PFE Recovery and Precision Endosulfan sulfate Heptachlor epoxide Seven replicate extractions were performed using 10-g samples of spiked soil from a commercialsupplier. Hexane:acetone (1:1) was used as the extraction solvent, at 100 EC and 2000 psi, using a 5- min heating time and a 5-min static extraction. Data are adapted from Reference 14.
These data are provided for guidance purposes only.
EXAMPLE SINGLE-LABORATORY ORGANOCHLORINE PESTICIDES DATA FROM THREE SOIL MATRICES SPIKED AT 250 TO 500 PPB AND EXTRACTED USING METHOD 3545 (PRESSURIZED FLUID EXTRACTION) PFE Recovery and Precision Endosulfan sulfate Heptachlor epoxide Seven replicate extractions were performed using 10-g samples of spiked soil from a commercialsupplier. Hexane:acetone (1:1) was used as the extraction solvent, at 100 EC and 2000 psi, using a 5- min heating time and a 5-min static extraction. Data are adapted from Reference 14.
These data are provided for guidance purposes only.
EXAMPLE SINGLE-LABORATORY ORGANOCHLORINE PESTICIDES DATA FROM A REAL-WORLD SOIL MATRIX SPIKED AT THE 500 PPB LEVEL AND EXTRACTED USING METHOD 3546 (MICROWAVE EXTRACTION) Heptachlor epoxide Endosulfan aldehyde Endosulfan sulfate DDE and dieldrin are reported as the sum of the two compounds since they were not resolved by chromatography.
Concentrations of each analyte ranged from between 0.5 to 10 µg/g.
Data are taken from Reference 15.
These data are provided for guidance purposes only.
EXAMPLE SINGLE-LABORATORY COMPARISON OF METHOD 3546 (MICROWAVE EXTRACTION) AND METHOD 3540 (SOXHLET EXTRACTION) OF ORGANOCHLORINE PESTICIDES FROM A REAL-WORLD CONTAMINATED SOIL Microwave Extraction Results * Sample extracts were diluted 1:5 for these compounds.
Soil samples obtained from the US EPA Emergency Response Center archive bankthrough their contract laboratory, REAC (Edison, NJ). The single Soxhlet extraction wasperformed by REAC three years earlier and the long storage period is believed to accountfor the low DDE + dieldrin recovery in the present study.
DDE and dieldrin are reported as the sum of the compounds since they were not resolvedby chromatography.
Concentrations of each analyte ranged from between 0.5 to 10 µg/g.
Data are taken from Reference 15.
These data are provided for guidance purposes only.
EXAMPLE GAS CHROMATOGRAM OF THE MIXED ORGANOCHLORINE PESTICIDE STANDARD 30-m x 0.25-mm ID, DB-5 Temperature program: 100 EC (hold 2 min) to 160 EC at 15 EC/min, then at 5 EC/min to 270 EC; carrier He at 16 psi EXAMPLE GAS CHROMATOGRAM OF INDIVIDUAL ORGANOCHLORINE PESTICIDE 30-m x 0.25-mm ID, DB-5 Temperature program: 100 EC (hold 2 min) to 160 EC at 15 EC/min, then at 5 EC/min to 270 EC; carrier He at 16 psi.
EXAMPLE GAS CHROMATOGRAM OF INDIVIDUAL ORGANOCHLORINE PESTICIDE 30-m x 0.25-mm ID, DB-5 Temperature program: 100 EC (hold 2 min) to 160 EC at 15 EC/min, then at 5 EC/min to 270 EC; carrier He at 16 psi.
EXAMPLE GAS CHROMATOGRAM OF TOXAPHENE Toxaphene analyzed on an SPB-608 fused-silica open-tubular column. The GC operatingconditions were as follows: 30-m x 0.53-mm ID SPB-608. Temperature program: 200 EC (2 min hold) to 290 EC at 6 EC/min. EXAMPLE GAS CHROMATOGRAM OF STROBANE Strobane analyzed on a DB-5/DB-1701 fused-silica open-tubular column pair. The GCoperating conditions were as follows: 30-m x 0.53-mm ID DB-5 (1.5-µm film thickness) and 30-m x 0.53-mm ID DB-1701 (1.0-µm film thickness) connected to a J&W Scientific press-fit Y-shaped inlet splitter. Temperature program: 150 EC (0.5 min hold) to 190 EC (2 min hold) at 12 EC/min then to 275 EC (10 min hold) at 4 EC/min.
EXAMPLE GAS CHROMATOGRAM OF ORGANOCHLORINE PESTICIDES Organochlorine pesticides analyzed on a DB-5/DB-1701 fused-silica open-tubular column pair. The GC operating conditions were as follows: 30-m x 0.53-mm ID DB-5 (0.83-µm filmthickness) and 30-m x 0.53-mm ID DB-1701 (1.0-µm film thickness) connected to an 8-in.
injection tee (Supelco Inc.). Temperature program: 140 EC (2 min hold) to 270 EC (1 min hold) at 2.8 EC/min.

Source: http://batit.co:3000/uploads/sgc_register/reference/980191041/8081b_ORGANOCHLORINE_PESTICIDES_BY_GAS_CHROMATOGRAPHY.pdf

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Ifmbe proceedings 2503 - a tissue-equivalent radioluminescent fiberoptic probe for in-vivo dosimetry based on mn-doped lithium tetraborate

A tissue-equivalent radioluminescent fiberoptic probe for in-vivo dosimetry based on Mn-doped lithium tetraborate M. Santiago1,2, M. Prokic3, P. Molina1,2, J. Marcazzó1,2 and E. Caselli1,4 1 Instituto de Física Arroyo Seco, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil, Argentina 2 Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rivadavia 1917, 1033 Buenos Aires, Argentina