1、Designation: D7645 10Standard Test Method forDetermination of Aldicarb, Aldicarb Sulfone, AldicarbSulfoxide, Carbofuran, Methomyl, Oxamyl and Thiofanox inWater by Liquid Chromatography/Tandem MassSpectrometry (LC/MS/MS)1This standard is issued under the fixed designation D7645; the number immediatel
2、y following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test
3、method covers the determination of aldicarb,aldicarb sulfone, aldicarb sulfoxide, carbofuran, methomyl,oxamyl, and thiofanox (referred to collectively as carbamatesin this test method) in water by direct injection using liquidchromatography (LC) and detected with tandem mass spec-trometry (MS/MS). T
4、hese analytes are qualitatively and quan-titatively determined by this method. This method adheres tomultiple reaction monitoring (MRM) mass spectrometry.1.2 The Detection Verification Level (DVL) and ReportingRange for the carbamates are listed in Table 1.1.2.1 The DVL is required to be at a concen
5、tration at least3 times below the Reporting Limit (RL) and have a signal/noise ratio greater than 3:1. Fig. 1 displays the signal/noiseratios of the primary single reaction monitoring (SRM) transi-tions, and Fig. 2 displays the confirmatory SRM transitions atthe DVLs for the carbamates.1.2.2 The rep
6、orting limit is the concentration of the Level 1calibration standard as shown in Table 2 for the carbamates.1.3 UnitsThe values stated in SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety
7、concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to Water
8、D1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3694 Practices for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD3856 Guide for Good Laboratory Practices in Laborato-ries En
9、gaged in Sampling and Analysis of WaterD4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic and Inorganic ConstituentsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisE2554 Practice for Estimating and Monitoring the Unc
10、er-tainty of Test Results of a Test Method in a SingleLaboratory Using a Control Sample Program2.2 Other Documents:3EPApublication SW-846 Test Methods for Evaluating SolidWaste, Physical/Chemical MethodsEPA Method 531 Measurement of N-Methyl Carbamoy-loximes and N-Methyl Carbamates in Drinking Water
11、 byDirect Aqueous Injection HPLC with Post Column De-rivatizationEPA Method 531.2 Measurement ofN-Methylcarbamoyloximes and N-Methylcarbamates inWater by Direct Aqueous Injection HPLC with Postcol-umn Derivatization1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the
12、direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved June 1, 2010. Published July 2010. DOI: 10.1520/D7645-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.or
13、g. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from National Technical Information Service (NTIS), U.S. Depart-ment of Commerce, 5285 Port Royal Road, Springfield, VA, 22161 or at http:/www.epa.gov/epawaste/hazard/te
14、stmethods/index.htm.TABLE 1 Detection Verification Level and Reporting RangeAnalyteDVL(ng/L)Reporting Range(g/L)Aldicarb 250 1-100Aldicarb Sulfone 250 1-100Aldicarb Sulfoxide 250 1-100Carbofuran 250 1-100Methomyl 250 1-100Oxamyl 250 1-100Thiofanox 250 1-1001Copyright ASTM International, 100 Barr Har
15、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.FIG. 1 Example Primary SRM Chromatograms Signal/Noise RatiosFIG. 2 Example Confirmatory SRM Chromatograms Signal/Noise RatiosD7645 102EPA Method 538 Determination of Selected Organic Con-taminants in Drinking Water by Direct Aqu
16、eous Injection-Liquid Chromatography/Tandem Mass Spectrometry(DAI-LC/MS/MS)3. Terminology3.1 Definitions:3.1.1 carbamates, nin this test method, aldicarb, aldicarbsulfone, aldicarb sulfoxide, carbofuran, methomyl, oxamyl,and thiofanox collectively.3.1.2 detection verification level, DVL, na concentr
17、ationthat has a signal/noise ratio greater than 3:1 and is at least 3times below the Reporting Limit (RL).3.1.3 reporting limit, RL, nthe concentration of thelowest-level calibration standard used for quantification.3.2 Abbreviations:3.2.1 mMmillimolar, 1 3 10-3moles/L3.2.2 NDnon-detect3.2.3 pptpart
18、s per trillion, ng/L4. Summary of Test Method4.1 This is a performance based method, and modificationsare allowed to improve performance.4.2 For carbamate analysis, samples are shipped to the labacidified between 0C and 6C and analyzed within 14 days ofcollection. In the lab, the samples are spiked
19、with surrogates,filtered using a syringe driven filter unit, and analyzed directlyby LC/MS/MS.4.3 The carbamates, methomyl-13C2,15N (surrogate) andcarbofuran-13C6(surrogate) are identified by retention time andtwo SRM transitions. The target analytes and surrogate arequantitated using the primary SR
20、M transitions utilizing anexternal calibration. The final report issued for each samplelists the concentration of carbamates and the surrogate recov-eries.5. Significance and Use5.1 This test method has been developed in support of theNational Homeland Security Research Center, US EPA byRegion 5 Chi
21、cago Regional Laboratory (CRL).5.2 The N-methyl carbamate (NMC) pesticides: aldicarb,carbofuran, methomyl, oxamyl, and thiofanox have been iden-tified by EPAas working through a common mechanism. Theseaffect the nervous system by reducing the ability of enzymes.Enzyme inhibition was the primary toxi
22、cological effect ofregulatory concern to EPA in assessing the NMCs food,drinking water, and residential risks. In most of the country,NMC residues in drinking water sources are at levels that arenot likely to contribute substantially to the multi-pathwaycumulative exposure. Shallow private wells ext
23、ending throughhighly permeable soils into shallow, acidic ground waterrepresent what the EPA believes to be the most vulnerabledrinking water. Aldicarb sulfone and aldicarb sulfoxide arebreakdown products of aldicarb and should also be monitoreddue to their toxicological effects.45.3 This method has
24、 been investigated for use with reagent,surface, and drinking water for the selected carbamates:aldicarb, aldicarb sulfone, aldicarb sulfoxide, carbofuran,methomyl, oxamyl and thiofanox.6. Interferences6.1 Method interferences may be caused by contaminants insolvents, reagents, glassware, and other
25、apparatus producingdiscrete artifacts or elevated baselines. All of these materialsare demonstrated to be free from interferences by analyzinglaboratory reagent blanks under the same conditions assamples.6.2 All glassware is washed in hot water with detergent andrinsed in hot water followed by disti
26、lled water. The glasswareis then dried and heated in an oven at 250C for 15 to 30minutes. All glassware is subsequently cleaned with acetonefollowed by methanol.6.3 All reagents and solvents should be pesticide residuepurity or higher to minimize interference problems.6.4 Matrix interferences may be
27、 caused by contaminants inthe sample. The extent of matrix interferences can varyconsiderably from sample source depending on variations ofthe sample matrix.7. Apparatus7.1 LC/MS/MS System:7.1.1 Liquid Chromatography (LC) SystemA completeLC system is needed in order to analyze samples.5Any systemtha
28、t is capable of performing at the flows, pressures, controlledtemperatures, sample volumes, and requirements of the stan-dard may be used.7.1.2 Analytical ColumnWatersACQUITYUPLCt BEHC18, 2.1 3 100 mm, 1.7 m particle size was used to develop4Additional information about Carbamate pesticides can be f
29、ound on the Internetat http:/www.epa.gov (2010).5A Waters ACQUITY UltraPerformance Liquid Chromatography (UPLCt)System was used to develop this test method. All parameters in this test method arebased on this system and may vary depending on your instrument.TABLE 2 Concentrations of Calibration Stan
30、dards (PPB)Analyte/Surrogate LV 1 LV 2 LV 3 LV 4 LV 5 LV 6 LV 7 LV 8Aldicarb 1 5 10 25 35 50 75 100Aldicarb Sulfone 1 5 10 25 35 50 75 100Aldicarb Sulfoxide 1 5 10 25 35 50 75 100Carbofuran 1 5 10 25 35 50 75 100Methomyl 1 5 10 25 35 50 75 100Oxamyl 1 5 10 25 35 50 75 100Thiofanox 1 5 10 25 35 50 75
31、 100Carbofuran-13C6(Surrogate) 1 5 10 25 35 50 75 100Methomyl-13C2,15N (Surrogate) 1 5 10 25 35 50 75 100D7645 103this test method.Any column that achieves adequate resolutionmay be used. The retention times and order of elution maychange depending on the column used and need to be moni-tored.NOTE 1
32、Any column that can achieve baseline resolution of theseanalytes may be used. Baseline resolution simplifies data analysis and canreduce the chance of ion suppression, leading to higher limits of detection.7.1.3 Tandem Mass Spectrometer (MS/MS) SystemAMS/MS system capable of MRM analysis.6Any system
33、 that iscapable of performing at the requirements in this standard maybe used.7.2 Filtration Device:7.2.1 Hypodermic SyringeA Lock Tip Glass Syringe ca-pable of holding a Millext HV Syringe Driven Filter UnitPVDF 0.22 m or similar may be used.7.2.1.1 A 25 mL Lock Tip Glass Syringe size is recom-mend
34、ed since a 25 mL sample size is used in this test method.7.2.2 FilterMillext HV Syringe Driven Filter Unit PVDF0.22 m (Millipore Corporation, Catalog # SLGV033NS) orsimilar may be used.8. Reagents and Materials8.1 Purity of ReagentsHigh Performance Liquid Chroma-tography (HPLC) pesticide residue ana
35、lysis and spectropho-tometry grade chemicals shall be used in all tests. Unlessindicated otherwise, it is intended that all reagents shallconform to the Committee on Analytical Reagents of theAmerican Chemical Society.7Other reagent grades may beused provided they are first determined to be of suffi
36、cientlyhigh purity to permit their use without affecting the accuracy ofthe measurements.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Type 1 of Specification D1193. It must be demonstrated thatthis water does not contain con
37、taminants at concentrationssufficient to interfere with the analysis.8.3 GasesUltrapure nitrogen and argon.8.4 Acetonitrile (CAS # 75-05-8).8.5 Methanol (CAS # 67-56-1).8.6 Acetone (CAS # 67-64-1).8.7 Ammonium Formate (CAS # 540-69-2).8.8 Acetic Acid (Glacial, CAS # 64-19-7).8.9 Aldicarb (CAS # 116-
38、06-3).8.10 Aldicarb Sulfone (CAS # 1646-88-4).8.11 Aldicarb Sulfoxide (CAS # 1646-87-3).8.12 Carbofuran (CAS # 1563-66-2).8.13 Oxamyl (CAS # 23135-22-0).8.14 Methomyl (CAS # 16752-77-5).8.15 Thiofanox (CAS # 39196-18-4).8.16 Methomyl-13C2,15N (acetohydroxamate-13C2,15N,CAS # (unlabeled) 16752-77-5 )
39、.88.17 Carbofuran-13C6(Ring-13C6, CAS # (unlabeled) 1563-66-2).89. Hazards9.1 Normal laboratory safety applies to this method. Ana-lysts should wear safety glasses, gloves, and lab coats whenworking in the lab. Analysts should review the Material SafetyData Sheets (MSDS) for all reagents used in thi
40、s method.10. Sampling10.1 Sampling and PreservationGrab samples should becollected in $25 mL pre-cleaned amber glass bottles withTeflont lined caps demonstrated to be free of interferences.Allsamples are acidified with glacial acetic acid to pH #3.8 uponcollection. A few drops or less of glacial ace
41、tic acid is requiredper 40 mL water sample collected. Chlorinated drinking watersamples are also dechlorinated with ascorbic acid; 10 mg ofascorbic acid is added to each 40 mL volume of water prior tocollection. Drinking water samples must be dechlorinated uponcollection. Aldicarb oxidizes when resi
42、dual chlorine is presentin the sample. This test method is based on a 25 mL samplesize per analysis. If different sample sizes are used, spikingsolution amounts and preservatives will need to be modified.Conventional sampling practices should be followed. Refer toGuide D3856 and Practices D3694. Sto
43、re samples between 0Cand 6C from the time of collection until analysis. Analyze thesample within 14 days of collection.NOTE 2Less sample volume is acceptable, but the spike amounts andsample preservatives must be adjusted accordingly.10.1.1 EPA Method 531.2 demonstrated that carbamates aremore stabl
44、e under acidic conditions. Potassium dihydrogencitrate buffer is used in Method 531.2 to bring the pH to 3.8,but this buffer is incompatible with LC/MS/MS. Therefore, thepH adjustment is accomplished with acetic acid in this testmethod. EPA Method 531.2 demonstrated that carbamatesunder acidic condi
45、tions are stable for at least 28 days. EPAMethod 531 demonstrated that oxamyl and methomyl arestable for at least 70 days at pH 3 60.2. Holding time isdependent upon your individual matrix and will vary. PracticeD4841 may be used to conduct a holding time study on yourindividual matrix.11. Preparati
46、on of LC/MS/MS11.1 LC Chromatograph Operating Conditions:511.1.1 Injection volumes of all calibration standards andsamples are made at 50 L volume using a full loop injection.If a 50 L volume loop is installed in the LC, a “full loop”mode is the preferred technique when performing fast, quali-tative
47、 analyses. This mode should be used whenever accuracyand precision are the primary concerns. The first sampleanalyzed after the calibration curve is a blank to ensure there isno carry-over. The gradient conditions for the liquid chromato-graph are shown in Table 3.6A Waters Quattro Premiery XE tande
48、m quadrupole mass spectrometer wasused to develop this test method.All parameters in this test method are based on thissystem and may vary depending on your instrument.7Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, D.C. For Suggestions on the test
49、ing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia andNational Formulators, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.8A source for the labeled carbamates is Cambridge Isotope Laboratories, 50Frontage Road, Andover, MA 01810-5413.D7645 104NOTE 3If your instrument does not have a 50 L injection capabilitya different volume may be used. This is a performance-based method andmodifications are allowed as long as min
