1、Designation: D7598 16 (Reapproved 2017)Standard 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 y
2、ear 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 procedure covers the determination of thiodiglyc
3、ol(TDG) in surface 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
4、has been developed by U.S. EPARegion 5 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 D
5、VL is required to be 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 thi
6、s testmethod is 100 g/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 prio
7、r to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBa
8、rriers to Trade (TBT) Committee.2. Referenced 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 Laborator
9、iesEngaged in Analysis of WaterD3694 Practices 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 Re
10、sults of a Test Method Using ControlChart Techniques2.2 Other Documents:U.S. EPA publication SW-846 Test Methods for EvaluatingSolid Waste, 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
11、 Specific to This Standard:3.2.1 detection verification level, DVL, na concentrationthat has a signal/noise ratio greater than 3:1 and is at least threetimes below the reporting limit (RL).3.2.2 independent reference material, IRM, na material ofknown purity and concentration obtained either from th
12、eNational Institute of Standards andTechnology (NIST) or otherreputable supplier. The IRM shall be obtained from a differentlot of material than is used for calibration.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.06 o
13、n Methods forAnalysis forOrganic Substances in Water.Current edition approved June 15, 2017. Published July 2017. Originallyapproved in 2009. Last previous edition approved in 2016 as D7598 16. DOI:10.1520/D7598-16R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AS
14、TM Customer Service at serviceastm.org. 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
15、 http:/www.epa.gov/epawaste/hazard/testmethods/index.htm.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established
16、in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.3 Acronyms:3.3.1 CCC, nContinuing Calibration Check3.3.2 IC, nInitial Calibration3.3.3 LC, nLiquid Chromatogra
17、phy3.3.4 LCS/LCSD, nLaboratory Control Sample/Laboratory Control Sample Duplicate3.3.5 MDL, nMethod Detection Limit3.3.6 MeOH, nMethanol3.3.7 mM, nmillimolar,1103moles/L3.3.8 MRM, nMultiple Reaction Monitoring3.3.9 MS/MSD, nMatrix Spike/Matrix Spike Duplicate3.3.10 NA, adjNot Available3.3.11 ND, nno
18、n-detect3.3.12 P Millex is a trademark of Merck KGAA,Darmstadt, Germany) 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,
19、 Washington, DC. For Suggestions on the testing of reagents notlisted 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.
20、 1 Example SRM Chromatograms Signal/Noise at Detection Verification LevelTABLE 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 1 000 2 500 5 000 10 0003,3-Thiodipropanol 100 250 500 1 000 2 500 5 000 10 000D7598 16 (2017)38.
21、9 Thiodiglycol (CAS # 111-48-8).8.10 3,3-Thiodipropanol (CAS # 10595-09-2).9. 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 Safety DataSheets (SDS) for all reagents used in th
22、is 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. Refer to Gu
23、ide 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 standards andsample
24、s 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 % Water;Time: 5 mi
25、nutes.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 analysis of TD
26、G.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 quantitation. This stand
27、ard 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 is set in the
28、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 Resolution 1: 14.5
29、Ion 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 secondsRepeats: 1Span:
30、 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 method, the fol
31、lowingprocedures 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 calibration stockstanda
32、rd 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 willproduce sta
33、ndards 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) byadding to a 100
34、-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 the individua
35、l 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 24 hours toen
36、sure optimum results. Stock calibration standards are rou-tinely replaced every six months if not previously discarded forquality control failure. Calibration standards are not filtered.TABLE 3 Gradient Conditions for Liquid ChromatographyTime(min)Flow(L/min)PercentCH3CNPercentWaterPercent500 mmolar
37、AmmoniumFormate/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 5D7598 16 (2017)412.2.3 Inject each standard and obtain a chromatogram foreach one. An external calibration is used monitoring the SRMtransition of each analyte. Calibration software is utilized
38、toconduct 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 standard.12.
39、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 generate line
40、arregression 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 givemore e
41、mphasis 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 thecali
42、bration 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 retention t
43、ime 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 the re
44、tention 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 same cal
45、ibration 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 correct
46、ed 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 standar
47、d 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 may b
48、e 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 solution
49、s 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 with 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 majo
