1、Designation: D7730 11Standard Test Method forDetermination of Dioctyl Sulfosuccinate in Sea Water byLiquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)1This standard is issued under the fixed designation D7730; the number immediately following the designation indicates the year oforiginal adop
2、tion 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 dioctylsulfosuccinate (DOSS)
3、in sea water by direct injection usingliquid chromatography (LC) and detection with tandem massspectrometry (MS/MS). This analyte is qualitatively and quan-titatively determined by this method. This method adheres toselected reaction monitoring (SRM) mass spectrometry.1.2 The Detection Verification
4、Level (DVL) and ReportingRange for DOSS are listed in Table 1.1.2.1 The DVL is required to be at a concentration at least3 times below the Reporting Limit (RL) and have a signal/noise ratio greater than 3:1. Fig. 1 and Fig. 2 display thesignal/noise ratio of the selected reaction monitoring (SRM)tra
5、nsition.1.2.2 The reporting limit is the concentration of the Level 1calibration standard as shown in Table 5 for DOSS, taking intoaccount the 50% sample preparation dilution factor.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thissta
6、ndard.1.4 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. Refere
7、nced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on Water2.2 Other Standards:3EPA publication SW-846, Test Methods for EvaluatingSolid Waste, Physical/Chemical Methods3. Terminolog
8、y3.1 Definitions:3.1.1 detection verification level, DVL, n a concentrationthat has a signal/noise ratio greater than 3:1 and is at least 3times below the Reporting Limit (RL).3.1.2 reporting limit, RL, nthe concentration of thelowest-level calibration standard used for quantification.3.2 Abbreviati
9、ons:3.2.1 ppbparts per billion, g/L3.2.2 mMmillimolar,1x10-3moles/L3.2.3 NAno addition3.2.4 NDnon-detect4. Summary of Test Method4.1 This is a performance based method, and modificationsare allowed to improve performance.4.2 For DOSS analysis, samples are shipped to the labbetween 0C and 6C and anal
10、yzed within 5 days. In the lab,the entire collected 20 mL sample is spiked with surrogate,ammonium formate buffer solution and brought to a volume of40 mL with acetonitrile. This prepared sample is then filteredusing a syringe driven filter unit, and analyzed by LC/MS/MS.If visible oil is present, t
11、he prepared sample is allowed to settleresulting in an oil layer at the top of the 40 mL solution. Aportion of the aqueous (bottom) layer is filtered, leaving the oillayer behind, through a syringe driven filter assembly andanalyzed by LC/MS/MS.1This test method is under the jurisdiction of ASTM Com
12、mittee D19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved May 1, 2011. Published July 2011. DOI: 10.1520/D773011.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custom
13、er 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 http:/ww
14、w.epa.gov/epawaste/hazard/testmethods/index.htm1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3 DOSS and DOSS surrogate are quantitated by retentiontime and one SRM transition. The final report issued for eachsample lists the conc
15、entration of DOSS and the surrogaterecovery.5. Significance and Use5.1 DOSS is an anionic detergent that is approved by theFood and DrugAdministration and is used widely as a laxative,emulsifying, solubilizing and dispersing agent, and is used inthe cosmetic industry.4DOSS may also be used as a disp
16、ersingagent to treat oil. DOSS may be released into the environmentat levels that may be harmful to aquatic life. The US EPAaquatic life benchmark for DOSS is 40 ppb.55.2 This method has been investigated for use with reagentand sea water.6. Interferences6.1 Method interferences may be caused by con
17、taminants insolvents, reagents, glassware, and other 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 wi
18、th detergent andrinsed in hot water followed by distilled water. The glasswareis then dried and heated in an oven at 250C for 15 to 30minutes. All glassware is subsequently cleaned with methanolor 50% acetonitrile/50% water, or both.6.3 System contamination and surface binding are problem-atic as DO
19、SS is a surface active compound. It is important tothoroughly rinse sample containers with organic solvent toaccurately measure DOSS concentrations. Thorough rinsing ofall lab equipment is necessary to reduce contamination. Care-fully analyze blanks to ensure that the method minimizesDOSS carryover.
20、6.4 All reagents and solvents should be pesticide residuepurity or higher to minimize interference problems.6.5 Matrix interferences may be caused by contaminants inthe sample. The extent of matrix interferences can varyconsiderably from sample source depending on variations ofthe sample matrix.4Cod
21、e of Federal Regulations-Title 21: Food and Drugs, Part 172 available athttp:/www.gpoaccess.gov/cfr/index.html.5Additional information about DOSS is available at http:/www.epa.gov/bpspill/dispersant-methods.html (2010)TABLE 1 Detection Verification Level and Reporting RangeAnalyte DVL (g/L) Reportin
22、g Range (g/L)DOSS 3 20-400FIG. 1 Detection Verification Level Signal/Noise Ratio.D7730 1126.6 Sulfonate filters contribute significantly to backgroundinterference and should be avoided for this standard. Inaddition to sample filtration, sulfonate filters may be present inwater purification systems.7
23、. Apparatus7.1 LC/MS/MS System7.1.1 Liquid Chromatography SystemA complete LC sys-tem is needed in order to analyze samples.6Any system that iscapable of performing at the flows, pressures, controlledtemperatures, sample volumes, and requirements of the stan-dard may be used.7.1.2 Analytical ColumnW
24、atersAtlantisy dC18, 2.1 x150 mm, 3 m particle size was used to develop this testmethod. Any column that achieves baseline resolution of theseanalytes may be used. Baseline resolution simplifies dataanalysis and can reduce the chance of ion suppression, leadingto higher limits of detection. The rete
25、ntion times and order ofelution may change depending on the column used and need tobe monitored.7.1.3 Tandem Mass Spectrometer SystemA MS/MS sys-tem capable of MRM analysis.7Any system that is capable ofperforming at the requirements in this standard may be used.7.2 Filtration Device7.2.1 Hypodermic
26、 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 Lock Tip Glass Syringe was used in this testmethod.7.2.2 FilterMillext HV Syringe Driven Filter Unit PVDF0.22 m (Millipore Corporation, Catalog # SLGV033NS) orsimi
27、lar may be used.8. Reagents and Materials8.1 Purity of ReagentsHigh Performance Liquid Chroma-tography (HPLC) pesticide residue analysis and spectropho-tometry grade chemicals shall be used in all tests. Unlessindicated otherwise, it is intended that all reagents shallconform to the Committee on Ana
28、lytical Reagents of theAmerican Chemical Society.8Other reagent grades may beused provided they are first determined to be of sufficientlyhigh purity to permit their use without affecting the accuracy ofthe measurements.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be under
29、stood to mean reagent water conformingto Type 1 of Specification D1193. It must be demonstrated thatthis water does not contain contaminants at concentrationssufficient to interfere with the analysis.8.3 GasesUltrapure nitrogen and argon.8.4 Acetonitrile (CH3CN, CAS # 75-05-8).8.5 Methanol (CAS # 67
30、-56-1).8.6 Ammonium formate (NH4CO2H, CAS # 540-69-2).8.7 2-Propanol (CAS # 67-63-0).6A 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.7A Wa
31、ters Quattro Premiery XE tandem 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.8Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, D.
32、C. 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 Pharmacopeia andNational Formulators, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 2 Reporting
33、 Level Signal/Noise Ratio.D7730 1138.8 Dioctyl sulfosuccinate (DOSS) purchased as the sodiumsalt (CAS # 577-11-7).8.9 Dioctyl sulfosuccinate-13C4, (bis(2-ethylhexyl) sulfos-uccinate (Fumaric acid-13C4) sodium salt (Unlabeled CAS #577-11-7), (Optional Surrogate, custom synthesis).8.10 Dioctyl sulfosu
34、ccinate-D34(DOSS-D34), bis(2-ethylhexyl-D17) sulfosuccinate sodium salt (Unlabeled CAS #577-11-7).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 Material SafetyData Sheets (
35、MSDS) for all reagents used in this method.10. Sampling10.1 Sampling and PreservationGrab samples should becollected in 20 mL pre-cleaned glass vials with Teflont linedsepta caps demonstrated to be free of interferences. This testmethod is based on a 20 mL sample size per analysis. Eachsample should
36、 be collected in duplicate and a quadruplicatesample must be included with each sample batch of 10 forMS/MSD quality control analyses. Store samples between 0Cand 6C from the time of collection until analysis. Analyze thesample within 5 days of collection.10.2 DOSS is surface active. The surface act
37、ivity results inDOSS adhering to many materials. Sampling techniques thatexpose samples to materials other than the sample containermay reduce DOSS concentration in samples. Sampling tech-niques such as peristaltic pumping expose the sample to largesurface areas compared to sample volume. Grab sampl
38、ingtechniques should be used. Transferring of sample from aninitial collection device to sampling vial may result in biasedlow DOSS concentrations and must be avoided.11. Preparation of LC/MS/MS11.1 LC Chromatograph Operating Conditions611.1.1 Injection volumes of all calibration standards andsample
39、s are made at 50 L volume using a full loop injection.“Full loop” mode is the preferred technique when performingquantitative analyses. Multiple blank samples should be ana-lyzed at the beginning of a run to remove residual DOSS fromthe system. The first sample analyzed after the calibrationcurve is
40、 a blank to ensure there is negligible (Less than theDVL) DOSS carry-over. The gradient conditions for the liquidchromatograph are shown in Table 2. Divert the column flowaway from the electrospray source for 0 to 5 minutes afterinjection. Flow diversion to waste may be done using the massspectromet
41、er divert valve, divert tubing configurations varyfrom manual injection. Test the divert valve configuration andoperation prior to analysis. Seawater samples contain nonvola-tile salts; the elution from injection to 5 minutes after injectionis diverted to waste in order to prevent mass spectrometers
42、ource contamination. If there is carry-over from one sample toanother, greater than half the reporting limit, the initial per-centage of acetonitrile should be raised as shown in Table 3 totry and remove the carry-over. This will shorten the elutiontime of DOSS approximately 1 minute; therefore it i
43、s necessaryreduce the flow diversion and adjust the MRM time. Increasingthe initial acetonitrile gradient concentration does not increasethe DVL or reporting limit.11.2 LC Sample Manager Conditions:11.2.1 Wash SolventsWeak wash is 4.0 mL of 50%water/50% acetonitrile. Strong wash is 2.0 mL of 60%acet
44、onitrile/40% 2-propanol. The strong wash solvent isneeded to eliminate carry-over between injections of DOSSsamples. The weak wash is used to remove the strong washsolvent. Instrument manufacturer specifications should be fol-lowed in order to eliminate sample carry-over.11.2.2 TemperaturesColumn, 3
45、5C; Sample compart-ment, 15C.11.2.3 Seal WashSolvent: 50% acetonitrile/50% water;Time: 2 minutes.11.3 Mass Spectrometer Parameters7:11.3.1 To acquire the maximum number of data points perSRM channel while maintaining adequate sensitivity, the tuneparameters may be optimized according to your instrum
46、ent.Each peak requires at least 10 scans per peak for adequatequantitation. This procedure will contain one surrogate, whichis isotopically labeled DOSS, DOSS-quantitation and DOSS-confirmation are in one MRM acquisition function to optimizesensitivity. Variable parameters regarding retention times,
47、SRM transitions, and cone and collision energies are shown inTable 4. Mass spectrometer parameters used in the develop-ment of this method are listed below:The instrument is set in the Electrospray negative sourcesetting.Capillary Voltage: 3.5 kVCone: Variable depending on analyte (Table 4)Extractor
48、: 2 VoltsRF Lens: 0.3 VoltsSource Temperature: 120CDesolvation Temperature: 350CDesolvation Gas Flow: 800 L/hrCone Gas Flow: 25 L/hrLow Mass Resolution 1: 14.0High Mass Resolution 1: 14.0Ion Energy 1: 0.8Entrance Energy: -1Collision Energy: Variable depending on analyte (Table 4)TABLE 2 Gradient Con
49、ditions for DOSS Liquid ChromatographyTime (min) Flow (mL/min) Percent 95% Water/ 5% CH3CN,5mMNH4CO2H Percent 95% CH3CN/ 5% Water, 5 mM NH4CO2H0.0 0.3 100 02.0 0.3 100 05.0 0.3 0 1008.0 0.3 0 1008.3 0.3 100 010.0 0.3 100 0D7730 114Exit Energy: 0Low Mass Resolution 2: 14.0High Mass resolution 2: 14.0Ion Energy 2: 1.0Multiplier: 650Gas Cell Pirani Gauge: 7.0 x 10-3TorrInter-Channel Delay: 0.02 secondsInter-Scan Delay: 0.01 secondsDwell: 0.1 secondsSolvent Delay: 5 minutes12. Calibration and Standardization12.1 The mass spectrometer must be cali
