1、Designation: D7645 14D7645 16Standard 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 i
2、mmediately 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 T
3、his procedure covers the determination of aldicarb, aldicarb sulfone, aldicarb sulfoxide, carbofuran, methomyl, oxamyl,and thiofanox (referred to collectively as carbamates in this test method) in water by direct injection using liquid chromatography(LC) and detected with tandem mass spectrometry (M
4、S/MS). These analytes are qualitatively and quantitatively determined by thistest method. This test method adheres to multiple reaction monitoring (MRM) mass spectrometry.1.2 The Detection Verification Level (DVL) and Reporting Range for the carbamates are listed in Table 1.1.2.1 The DVLis required
5、to be at a concentration at least 3 times below the Reporting Limit (RL) and have a signal/noise ratiogreater than 3:1. Fig. 1 displays the signal/noise ratios of the primary single reaction monitoring (SRM) transitions, and Fig. 2displays the confirmatory SRM transitions at the DVLs for the carbama
6、tes.1.2.2 The reporting limit is the concentration of the Level 1 calibration standard as shown in Table 2 for the carbamates.1.3 UnitsThe values stated in SI units are to be regarded as standard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to addres
7、s all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology
8、Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on WaterD3694 Practices for Preparation of Sample Containers and for Preservation of Organic ConstituentsD3856 Guide for Management Systems in Labo
9、ratories Engaged in Analysis of WaterD4841 Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic ConstituentsD5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water AnalysisE2554 Practice for Estimating and Monitoring the Unc
10、ertainty of Test Results of a Test Method Using Control Chart Techniques2.2 Other Documents:3EPA Publication SW-846 Test Methods for Evaluating Solid Waste, Physical/Chemical MethodsEPAMethod 531 Measurement of N-Methyl Carbamoyloximes and N-Methyl Carbamates in Drinking Water by DirectAqueousInject
11、ion HPLC with Post Column DerivatizationEPAMethod 531.2 Measurement of N-Methylcarbamoyloximes and N-Methylcarbamates in Water by DirectAqueous InjectionHPLC with Postcolumn Derivatization1 This test method is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of
12、Subcommittee D19.06 on Methods for Analysis forOrganic Substances in Water.Current edition approved Jan. 1, 2014Feb. 1, 2016. Published March 2014May 2016. Originally approved in 2010. Last previous edition approved in 20102014 as D7645 1014.1. DOI: 10.1520/D7645-14.10.1520/D7645-16.2 For referenced
13、ASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from National Technical Information Service (NTIS), U.S. Departme
14、nt of Commerce, 5285 Port Royal Road, Springfield, VA, 22161 or at http:/www.epa.gov/epawaste/hazard/testmethods/index.htm.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becausei
15、t may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr
16、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1EPA Method 538 Determination of Selected Organic Contaminants in Drinking Water by Direct Aqueous Injection-LiquidChromatography/Tandem Mass Spectrometry (DAI-LC/MS/MS)3. Terminology3.1 Definitions:3.1.1 For definitions of te
17、rms used in this standard, refer to Terminology D1129.3.2 Definitions:Definitions of Terms Specific to This Standard:3.2.1 carbamates, nin this test method, aldicarb, aldicarb sulfone, aldicarb sulfoxide, carbofuran, methomyl, oxamyl, andthiofanox collectively.3.2.2 detection verification level, DVL
18、, na concentration that has a signal/noise ratio greater than 3:1 and is at least 3 timesbelow the Reporting Limit (RL).3.2.3 reporting limit, RL, independent reference material, IRM, nthe concentration of the lowest-level calibration standardused for quantification. a material of known purity and c
19、oncentration obtained either from the National Institute of Standards andTechnology (NIST) or other reputable supplier. The IRM shall be obtained from a different lot of material than is used forcalibration.3.3 Abbreviations:Acronyms:3.3.1 CCC, nContinuing Calibration Check3.3.2 IC, nInitial Calibra
20、tion3.3.3 LC, nLiquid Chromatography3.3.4 LCS/LCSD, nLaboratory Control Sample/Laboratory Control Sample Duplicate3.3.5 MeOH, nMethanol3.3.6 mMmM, nmillimolar, 1 10-3 moles/L3.3.7 MRM, nMultiple Reaction Monitoring3.3.8 MS/MSD, nMatrix Spike/Matrix Spike Duplicate3.3.9 NA, adjNot Available3.3.10 NDN
21、D, nnon-detect3.3.11 P 10 mg of ascorbic acid is added to each 40 mL volume of water prior7 A Quattro Premier XE (trademark(a8) trademark of Waters Technologies Corporation in Wilmington, DE) tandem quadrupole mass spectrometer was used to developthis test method. All parameters in this test method
22、are based on this system and may vary depending on your instrument.8 The sole source of supply of the apparatus known to the committee at this time is Millipore Corporation, Catalog # SLGV033NS. If you are aware of alternative suppliers,please provide this information toASTM International Headquarte
23、rs. Your comments will receive careful consideration at a meeting of the responsible technical committee,AMillex HV Syringe Driven Filter Unit PVDF 0.22 m (Millipore Corporation, Catalog #SLGV033NS; Millex is a trademark of Merck KGAA, Darmstadt, Germany) has beenfound suitable for use for this test
24、 method, any filter unit may be used that meets the performance of this1 which you may attend.test method may be used.9 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, D.C. For Suggestions on the testing of reagents not listed bythe American Chemic
25、al Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulators, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.10 The Teflon trademark is owned by E. I. du Pont de Nemours and Company is a trademark of T
26、he Chemours Company, LLC, in Wilmington, DE.D7645 166to collection. Drinking water samples must be dechlorinated upon collection. Aldicarb oxidizes when residual chlorine is presentin the sample. This test method is based on a 25 mL sample size per analysis. If different sample sizes are used, spiki
27、ng solutionamounts and preservatives will need to be modified. Conventional sampling practices should be followed. Refer to Guide D3856and Practices D3694. Store samples between 0C and 6C from the time of collection until analysis. Analyze the sample within14 days of collection.NOTE 1Less sample vol
28、ume is acceptable, but the spike amounts and sample preservatives must be adjusted accordingly.10.1.1 EPA Method 531.2 demonstrated that carbamates are more stable under acidic conditions. Potassium dihydrogen citratebuffer is used in Method 531.2 to bring the pH to 3.8, but this buffer is incompati
29、ble with LC/MS/MS. Therefore, the pHadjustment is accomplished with acetic acid in this test method. EPA Method 531.2 demonstrated that carbamates under acidicconditions are stable for at least 28 days. EPAMethod 531 demonstrated that oxamyl and methomyl are stable for at least 70 daysat pH 3 6 0.2.
30、 Holding time is dependent upon your individual matrix and will vary. Practice D4841 may be used to conduct aholding time study on your individual matrix.11. Preparation of LC/MS/MS11.1 LC Chromatograph Operating Conditions:511.1.1 Injection volumes of all calibration standards and samples are made
31、at 50 L volume using a full loop injection. If a 50L volume loop is installed in the LC, a “full loop” mode is the preferred technique when performing fast, qualitative analyses.This mode should be used whenever accuracy and precision are the primary concerns. The first sample analyzed after thecali
32、bration curve is a blank to ensure there is no carry-over. The gradient conditions for the liquid chromatograph are shown inTable 3.11.2 LC Sample Manager Conditions:11.2.1 Wash SolventsWeak wash is 2.4 mLof 95 % water/5 % methanol. Strong wash is 1.2 mLof methanol. The strong washsolvent is needed
33、to eliminate carry-over between injections of carbamate samples. The weak wash is used to remove the strongwash solvent. Instrument manufacturer specifications should be followed in order to eliminate sample carry-over.11.2.2 TemperaturesColumn, 30C; Sample compartment, 15C.11.2.3 Seal WashSolvent:
34、50 Acetonitrile/50 Water; Time: 5 minutes.11.3 Mass Spectrometer Parameters:711.3.1 To acquire the maximum number of data points per SRM channel while maintaining adequate sensitivity, the tuneparameters may be optimized according to your instrument. Each peak requires at least 10 scans per peak for
35、 adequate quantitation.This test method contains two surrogates, which are isotopically labeled methomyl and carbofuran, and seven carbamates, whichare split up into seven MRM acquisition functions to optimize sensitivity. Variable parameters regarding retention times, SRMtransitions, and cone and c
36、ollision energies are shown in Table 4. Mass spectrometer parameters used in the development of thistest method are listed below:The instrument is set in the Electrospray positive source setting.Capillary Voltage: 3.5 kVCone: Variable depending on analyte (Table 4)Extractor: 2 VoltsRF Lens: 0.1 Volt
37、sSource Temperature: 120CDesolvation Temperature: 375CDesolvation Gas Flow: 800 L/hrCone Gas Flow: 25 L/hrLow Mass Resolution 1: 14.5High Mass Resolution 1: 14.5Ion Energy 1: 0.5Entrance Energy: 1Collision Energy: Variable depending on analyte (Table 4)Exit Energy: 0TABLE 3 Gradient Conditions for L
38、iquid ChromatographyTime(min)Flow(L/min)Percent95 % Water/5 % Methanol,5 mM NH4CO2HPercent95 % Methanol/5 % Water,5 mM NH4CO2H0.0 300 100 02.0 300 100 03.0 300 95 55.0 300 85 1510.0 300 0 10011.5 300 0 10012.0 300 100 014.0 300 100 0D7645 167Low Mass Resolution 2: 14.5High Mass resolution 2: 14.5Ion
39、 Energy 2: 0.7Multiplier: 650Gas Cell Pirani Gauge: 7.0 10-3 TorrInter-Channel Delay: 0.005 secondsInter-Scan Delay: 0.005 secondsDwell: 0.075 seconds12. Calibration and Standardization12.1 The mass spectrometer must be calibrated in accordance with manufacturer specifications before analysis. In or
40、der toobtain accurate analytical values through using this test method within the confidence limits, the following procedures must befollowed when performing the test method. Prepare all solutions in the lab using Class A volumetric glassware.12.2 Calibration and StandardizationTo calibrate the inst
41、rument, analyze eight calibration standards containing the eightconcentration levels of the carbamates, methomyl-13C2,15N and carbofuran-13C6 prior to analysis as shown in Table 2.Acalibrationstock standard solution is prepared from standard materials or they are purchased as certified solutions. St
42、ock Standard SolutionAcontaining the carbamates and surrogates is prepared at Level 8 concentration and aliquots of that solution are diluted to prepareLevels 1 through 7. The following steps will produce standards with the concentration values shown in Table 2. The analyst isresponsible for recordi
43、ng initial component weights carefully when working with pure materials and correctly carrying the weightsthrough the dilution calculations.12.2.1 Prepare Stock Standard SolutionA(Level 8) by adding to a 50 mLvolumetric flask individual solutions of the following:100 Lof aldicarb, aldicarb sulfone,
44、aldicarb sulfoxide, carbofuran, methomyl, oxamyl, and thiofanox, each at 50 ppm in methanoland 50 L of methomyl-13C2,15N in methanol and carbofuran-13C6 in 1,4-dioxane each at 100 ppm, dilute to 50 mL with water.The preparation of the Level 8 standard can be accomplished using different volumes and
45、concentrations of stock solutions as isaccustomed in the individual laboratory. Depending on the prepared stock concentrations, the solubility at that concentration willhave to be ensured.12.2.2 Aliquots of SolutionAare then diluted with water to prepare the desired calibration levels in 2-mLamber g
46、lass LC vials.The calibration vials must be used within 24 hours to ensure optimum results. Stock calibration standards are routinely replacedevery 7 days if not previously discarded for quality control failure. Calibration standards are not filtered.12.2.3 Inject each standard and obtain its chroma
47、togram. An external calibration technique is used to monitor the primary andconfirmatory SRM transitions of each analyte. Calibration software is utilized to conduct the quantitation of the target analytes andsurrogates using the primary SRM transition. The ratios of the primary/confirmatory SRM tra
48、nsition area counts are given in Table4 and will vary depending on the individual tuning conditions. The primary/confirmatory SRM transition area ratio must be within35 % of the individual labsaccepted primary/confirmatory SRM transition area ratio. The primary SRM transition of each analyteis used
49、for quantitation and the confirmatory SRM transition for confirmation.This gives added confirmation by isolating the parention, forming two product ions via fragmentation, and relating it to the retention time in the calibration standard.12.2.4 The calibration software manual should be consulted to use the software correctly. The quantitation method is set as anexternal calibration using the peak areas in ppt or ppb units, as long as the analyst is consistent. Concentrations may be calculatedusing the data system software to generate line
