1、Designation: D7598 16Standard Test Method forDetermination of Thiodiglycol in Water by Single ReactionMonitoring Liquid Chromatography/Tandem MassSpectrometry1This standard is issued under the fixed designation D7598; the number immediately following the designation indicates the year oforiginal ado
2、ption 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 procedure covers the determination of thiodiglycol(TDG) in surface
3、 water by direct injection using liquidchromatography (LC) and detected with tandem mass spec-trometry (MS/MS). TDG is qualitatively and quantitativelydetermined by this test method. This test method adheres tosingle reaction monitoring (SRM) mass spectrometry.1.2 This test method has been developed
4、 by US EPARegion5 Chicago Regional Laboratory (CRL).1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 The Detection Verification Level (DVL) and ReportingRange for TDG are listed in Table 1.1.4.1 The DVL is required to be
5、at a concentration at least3 times below the reporting limit (RL) and have a signal/noiseratio greater than 3:1. Fig. 1 displays the signal/noise ratio atthe DVL.1.4.2 The RL is the concentration of the level 1 calibrationstandard as shown in Table 2. The reporting limit for this testmethod is 100 g
6、/L.1.5 This standard does not purport to address all of thesafety 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. Reference
7、d Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD3694 Practic
8、es for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisE2554 Practice for Estimating and Monitoring the Uncer-tainty of Test Results of a Test Method Using ControlChart Te
9、chniques2.2 Other Documents:EPA publication SW-846 Test Methods for Evaluating SolidWaste, Physical/Chemical Methods33. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer toTerminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 detection verifi
10、cation level, DVL)=, na concentra-tion that has a signal/noise ratio greater than 3:1 and is at least3 times below the reporting limit (RL).3.2.2 independent reference material, IRM, na material ofknown purity and concentration obtained either from theNational Institute of Standards andTechnology (N
11、IST) or otherreputable supplier. The IRM shall be obtained from a differentlot of material than is used for calibration.3.3 Acronyms:3.3.1 CCC, nContinuing Calibration Check3.3.2 IC, nInitial Calibration3.3.3 LC, nLiquid Chromatography3.3.4 LCS/LCSD, nLaboratory Control Sample/Laboratory Control Sam
12、ple Duplicate1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved Feb. 1, 2016. Published May 2016. Originallyapproved in 2009. Last previous ed
13、ition approved in 2009 as D7598 092. DOI:10.1520/D7598-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Av
14、ailable 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/testmethods/index.htm.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Uni
15、ted States13.3.5 MDL, nMethod Detection Limit3.3.6 MeOH, nMethanol3.3.7 mM, nmillimolar,110-3moles/L3.3.8 MRM, nMultiple Reaction Monitoring3.3.9 MS/MSD, nMatrix Spike/Matrix Spike Duplicate3.3.10 NA, adjNot Available3.3.11 ND, nnon-detect3.3.12 P Millex is a trademark of Merck KGAA,Darmstadt, Germa
16、ny) has been found suitable for use for this test method, any filterunit may be used that meets the performance of this test method may be used.9Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted
17、 by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Example SRM Chromatograms Signal/Noise at Detection Verification L
18、evelTABLE 2 Concentrations of Calibration Standards (PPB)Analyte/Surrogate LV 1 LV 2 LV 3 LV 4 LV 5 LV 6 LV 7Thiodiglycol 100 250 500 1000 2500 5000 10 0003,3-Thiodipropanol100 250 500 1000 2500 5000 10 000D7598 163working in the lab. Analysts should review the Safety DataSheets (SDS) for all reagen
19、ts used in this test method.10. Sampling10.1 SamplingGrab samples must be collected in 25-mLpre-cleaned amber glass bottles with Teflon-lined caps demon-strated to be free of interferences. This test method requires a25-mL sample size per analysis. Conventional sampling prac-tices should be followed
20、. Refer to Guide D3856 and PracticesD3694.10.2 PreservationStore samples between 0C and 6Cfrom the time of collection until analysis. Analyze the samplewithin 1 day of collection.11. Preparation of LC/MS/MS11.1 LC Chromatograph Operating Conditions:511.1.1 Injection volumes of all calibration standa
21、rds andsamples are 50 L. The first sample analyzed after thecalibration curve is a blank to ensure there is no carry-over.Thegradient conditions for the liquid chromatograph are shown inTable 3.11.1.2 TemperaturesColumn, 30C; Samplecompartment, 15C.11.1.3 Seal WashSolvent: 50 % Acetonitrile/50 % Wat
22、er;Time: 5 minutes.11.1.4 Needle WashSolvent: 50 % Acetonitrile/50 % Wa-ter; Normal Wash, approximately 13 second wash time.11.1.5 Autosampler PurgeThree loop volumes.11.1.6 Specific instrument manufacturer wash/purge speci-fications should be followed in order to eliminate samplecarry-over in the a
23、nalysis of TDG.11.2 Mass Spectrometer Parameters:711.2.1 In order to acquire the maximum number of datapoints per SRM channel while maintaining adequatesensitivity, the tune parameters may be optimized according toyour instrument. Each peak requires at least 10 scans per peakfor adequate quantitatio
24、n. This standard contains only onetarget compound and one surrogate which are in different SRMexperiment windows in order to optimize the number of scansand sensitivity. Variable parameters regarding retention times,SRM Transitions and cone and collision energies are shown inTable 4.The instrument i
25、s set in the Electrospray (+) positive setting.Capillary Voltage: 3.5 kVCone: Variable depending on analyte (Table 4)Extractor: 2 VoltsRF Lens: 0.2 VoltsSource Temperature: 120CDesolvation Temperature: 300CDesolvation Gas Flow: 500 L/hrCone Gas Flow: 25 L/hrLow Mass Resolution 1: 14.5High Mass Resol
26、ution 1: 14.5Ion Energy 1: 0.5Entrance Energy: 1Collision Energy: Variable depending on analyte (Table 4)Exit Energy: 2Low Mass Resolution 2: 15High Mass resolution 2: 15Ion Energy 2: 0.5Multiplier: 650Gas Cell Pirani Gauge: 3.3 103TorrInter-Channel Delay: 0.02 secondsInter-Scan Delay: 0.1 secondsRe
27、peats: 1Span: 0 DaltonsDwell: 0.1 Seconds12. Calibration and Standardization12.1 The mass spectrometer must be calibrated per manu-facturer specifications before analysis. In order that analyticalvalues obtained using this test method are valid and accuratewithin the confidence limits of the test me
28、thod, the followingprocedures must be followed when performing the test method.12.2 Calibration and StandardizationTo calibrate theinstrument, analyze seven calibration standards containing theseven concentration levels of TDG and 3,3-thiodipropanolprior to analysis as shown in Table 2. A calibratio
29、n stockstandard solution is prepared from standard materials orpurchased as certified solutions. Stock standard solution A(Level 7) containing TDG and 3,3-thiodipropanol is preparedat Level 7 concentration and aliquots of that solution arediluted to prepare Levels 1 through 6. The following steps wi
30、llproduce standards with the concentration values shown inTable 2. The analyst is responsible for recording initialcomponent weights carefully when working with pure materi-als and correctly carrying the weights through the dilutioncalculations.12.2.1 Prepare stock standard solution A (Level 7) byad
31、ding to a 100-mL volumetric flask individual methanolsolutions of the following: 250 L of TDG and 3,3-thiodipropanol each at 4 g/L, dilute to 100 mL with water. Thepreparation of the Level 7 standard can be accomplished usingdifferent volumes and concentrations of stock solutions as isaccustomed in
32、the individual laboratory. Depending on stockconcentrations prepared, the solubility at that concentrationwill have to be ensured.12.2.2 Aliquots of Solution A are then diluted with water toprepare the desired calibration levels in 2-mL amber glass LCvials. The calibration vials must be used within
33、24 hours toensure optimum results. Stock calibration standards are rou-tinely replaced every six months if not previously discarded forquality control failure. Calibration standards are not filtered.12.2.3 Inject each standard and obtain a chromatogram foreach one. An external calibration is used mo
34、nitoring the SRMtransition of each analyte. Calibration software is utilized toTABLE 3 Gradient Conditions for Liquid ChromatographyTime(min)Flow(L/min)PercentCH3CNPercentWaterPercent500 mmolarAmmoniumFormate/2%Formic Acid0 300 0 95 52.5 300 0 95 56 300 90 5 510 300 90 5 512 300 0 95 516 300 0 95 5D
35、7598 164conduct the quantitation of the target analyte and surrogate.The SRM transition of each analyte is used for quantitation andconfirmation. This gives confirmation by isolating the parention, fragmenting it to the product ion, and also relating it to theretention time in the calibration standa
36、rd.12.2.4 The calibration software manual should be consultedto use the software correctly. The quantitation method is set asan external calibration using the peak areas in ppb or ppm unitsas long as the analyst is consistent. Concentrations may becalculated using the data system software to generat
37、e linearregression or quadratic calibration curves. Forcing the calibra-tion through the origin is not recommended.12.2.5 Linear calibration may be used if the coefficient ofdetermination, r2, is 0.98 for the analyte. The point of originis excluded and a fit weighting of 1/X is used in order to give
38、more emphasis to the lower concentrations. If one of thecalibration standards other than the high or low point causesthe r2of the curve to be 0.99 for the analyte. The point oforigin is excluded and a fit weighting of 1/X is used in order togive more emphasis to the lower concentrations. If one of t
39、hecalibration standards, other than the high or low, causes thecurve to be 0.99. In thisevent, the reporting range must be modified to reflect thischange. Each calibration point used to generate the curve musthave a calculated percent deviation less than 25 % from thegenerated curve.12.2.7 The reten
40、tion time window of the SRM transitionsmust be within 5 % of the retention time of the analyte in amidpoint calibration standard. If this is not the case, re-analyzethe calibration curve to determine if there was a shift inretention time during the analysis and the sample needs to bere-injected. If
41、the retention time is still incorrect in the sample,refer to the analyte as an unknown.12.2.8 A midpoint calibration check standard must be ana-lyzed at the end of each batch of 20 samples or within 24 hoursafter the initial calibration curve was generated. This endcalibration check should be the sa
42、me calibration standard thatwas used to generate the initial curve. The results from the endcalibration check standard must have a percent deviation lessthan 30 % from the calculated concentration for the targetanalyte and surrogate. If the results are not within these criteria,the problem must be c
43、orrected and either; all samples in thebatch must be re-analyzed against a new calibration curve, orthe affected results must be qualified with an indication thatthey do not fall within the performance criteria of the testmethod. If the analyst inspects the vial containing the endcalibration check s
44、tandard and notices that the sample evapo-rated affecting the concentration, a new end calibration checkstandard may be made and analyzed. If this new end calibrationcheck standard has a percent deviation less than 30 % from thecalculated concentration for the target analyte and surrogate theresults
45、 may be reported unqualified.12.3 All samples are prepared using Class A glass volumet-ric glassware. The sample volume used throughout this testmethod is 25 mL. Every sample, the entire 25-mL volume, isfiltered through the filtration device described in Section 7.2only after all required spiking so
46、lutions are added and mixedthroughout the sample.12.3.1 Anew filter unit is used for each sample. The syringemust be cleaned between each filtration. It is the analystsresponsibility to ensure that the syringe is clean. A possibleway of cleaning the syringe between filtrations is first byrinsing wit
47、h at least 5 syringe volumes of water, followed by atleast 3 volumes of acetone, then 3 volumes of methanol andfinally rinsed with water to remove any residual solvent.12.4 If a laboratory has not performed the test before or ifthere has been a major change in the measurement system, forexample, new
48、 analyst, new instrument, etc., perform a preci-sion and bias study to demonstrate laboratory capability.12.4.1 Analyze at least four replicates of a sample solutioncontaining TDG and 3,3-thiodipropanol at a concentration inthe calibration range of Levels 3 to 5.The matrix and chemistryshould be sim
49、ilar to the solution used in this test method. Eachreplicate must be taken through the complete analytical testmethod including any sample preservation and pretreatmentsteps.12.4.2 Calculate the mean (average) percent recovery andrelative standard deviation (RSD) of the four values andcompare to the acceptable ranges of the quality control (QC)acceptance criteria for the Initial Demonstration of Perfor-mance in Table 5.12.4.3 This study should be repeated until the single opera-tor precision and mean recovery are within the limits in Tab
