1、Designation: D2023 89 (Reapproved 2016)Standard Test Method ofAnalysis for Sodium Toluene Sulfonate in Detergents1This standard is issued under the fixed designation D2023; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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 method covers the analysis for the apparentsodium toluene sulfonate (NaTS) content of detergents.1.2 The v
3、alues stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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
4、safety and health practices and determine the applica-bility of regulatory limitations prior to use. Material SafetyData sheets are available for reagents and materials. Reviewthem for hazards prior to usage.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent Water3. Summary o
5、f Test Method3.1 This test method is based on the separation of the lowmolecular weight sulfonate from interfering higher molecularweight sulfonates and determination by ultraviolet absorption.The higher molecular weight sulfonates are extracted assulfonic acids in a hydrochloric acid solution using
6、 ethyl etheras the solvent.4. Significance and Use4.1 This test method is of use to anyone engaged incompositional analysis of detergent formulations. This wouldinclude formulators, and analysts employed by companies thatmanufacture the components usually included in such formu-lations.5. Interferen
7、ces5.1 Any low molecular weight substituted benzene sul-fonate or benzene sulfonate (NaBS) itself will interfere andgive an apparent toluene sulfonate figure. Since the method isstandardized using p-toluene sulfonate, o-sulfonate will not beassayed correctly. When contamination is suspected, it shou
8、ldbe checked by running a complete absorption curve andcomparing with known samples.6. ApparatusNOTE 1Absolute cleanliness of apparatus is essential. Use glassapparatus only. Contact with rubber, cork, or hands will introduceabsorbance errors.6.1 Separatory Funnels, 500-mL capacity, glass-stoppered,
9、pear-shaped.6.2 Balance, analytical.6.3 Spectrophotometer (Note 2), with necessary ultravioletaccessories for working in the range from 230 to 300 nm.These include 1.00 and 5.00-cm absorption cells with quartzwindows.NOTE 2Details of the test method as written are based on the use ofthe Beckman DU o
10、r Cary recording spectrophotometers. Equivalentspectrophotometers also may be used, provided suitable modifications canbe made in the details of the method.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents
11、shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccur
12、acy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D1193.1This test method is under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergents and is the direct responsibility of Sub
13、committee D12.12 onAnalysis and Specifications of Soaps, Synthetics, Detergents and their Components.Current edition approved July 1, 2016. Published August 2016. Originallyapproved in 1962 as D2023 62 T. Last previous edition approved in 2009 asD2023 89(2009). DOI: 10.1520/D2023-89R16.2For referenc
14、ed 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.3Reagent Chemicals, American Chemical Society Specifications, AmericanChem
15、ical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rock
16、ville,MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17.3 Ethyl Ether.7.4 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).7.5 Hydrochloric Acid (1+3)Mix 1 volume of concen-trated HCl with 3 volumes of water.7.6
17、p-Toluenesulfonic Acid Sodium Salt (NaTS)4Dry for24 h at 105C and store in a desiccator. Use for preparation ofstandards.7.7 Sodium Sulfate (Na2SO4), anhydrous.8. Precaution8.1 This test method includes ethyl ether extraction from anacidic solution. Appropriate safety practices, such as thoseinclude
18、d in the Material Safety Data Sheets for ethyl ether,should be employed. Especially important is adequate eyeprotection to guard against spattering.9. Preparation of Standards9.1 Weigh 0.25 6 0.0001 g of the standard NaTS, dissolvein water, and dilute to the mark in a 100-mL volumetric flask.Mix tho
19、roughly. From this solution make pipettings as follows:9.1.1 For the Cary spectrophotometer and 5-cm cells (Note2), take 50 mL (b = cell length).9.1.2 For the Beckman DU spectrophotometer and 5-cmcells (Note 2), take 10 mL (b = cell length).NOTE 3If 1.0-cm cells are used, the concentration must be i
20、ncreasedaccordingly.9.2 Place the indicated volume of solution in 250-mLvolumetric flask. Add to the flask 10.0 g of Na2SO4and 60 mLof HCl. Dilute to the mark with water and mix thoroughly.From the 250-mL volumetric flask, pipet 25 mL into a 100-mLvolumetric flask, dilute to volume with water and mi
21、x thor-oughly. The concentration, c, in this final dilution will be 0.125g/L for Cary and 0.025 g/L for Beckman instruments.9.3 Prepare a blank solution with water, Na2SO4, and HCl,but without NaTS, exactly as described for standards.9.4 Measure the absorbance of the dilute standard solutionagainst
22、the blank over the range 230 to 300 nm. Determine themaximum absorption near 261 nm and the absorption atwavelengths 19 nm above and below the maximum. If anon-recording instrument is used, determine the peak absor-bance and read the reference points 19 nm above and below.Correct the absorbance near
23、 261 nm by subtracting one half thesum of the absorbances at 19 nm below and 19 nm above thepeak wavelength.9.5 Calculate the absorptivity, a, of the standard solution asfollows:a 5 corrected absorbance near 261 nm/bc (1)10. Procedure10.1 Weigh 10.00 6 0.01 g of the sample of syntheticdetergent to b
24、e analyzed and dissolve in about 75 mL of hotwater. Transfer to a 500-mL glass-stoppered, pear-shaped,separatory funnel; add 10.0 g of Na2SO4and 40 mL of HCl.Swirl to dissolve and cool to room temperature.10.2 Extract twice with 100-mL portions of ethyl ether,shaking vigorously during each extractio
25、n. Caution: see 8.1.Combine the ether extracts and wash them with three 25-mLportions of 1 + 3 HCl to ensure complete removal of sodiumions. Add these extracts to the extracted acid aqueous solutionand extract once more with 100 mL of ether. Allow to settle for15 to 30 min, or until clear, and draw
26、off the acid water layerinto a beaker and evaporate the ether, on a steam bath. Filterthis solution if not clear, preferably through a glass fiber filter.10.3 Discard all ether extracts. Transfer the acid watersolution, free of ether, to a 250-mL glass-stoppered, volumetricflask. Dilute to the mark
27、with water and mix thoroughly. Thissolution contains all of the NaTS or NaBS free of syntheticdetergent sulfonates.10.4 For the Cary spectrophotometer, pipet 10 mL of thissolution into a 100-mL glass-stoppered volumetric flask anddilute to volume with water. Mix thoroughly and makeabsorbance measure
28、ments against a blank diluted in a similarmanner which contains water, HCl, and Na2SO4only. Absor-bance measurements should be made in a 5-cm cell (Note 3)exactly as described in Section 5 (c = 4.00 g L).10.5 For the Beckman DU spectrophotometer, pipet 25 mLfrom the 250-mL volumetric flask into anot
29、her 250-mL volu-metric flask. Dilute to the mark with water, mix, and pipet 25mL of this solution into a 100-mL volumetric flask. Dilute,mix, and make absorbance readings against a blank similarlyprepared with reagents as described in Section 5 (c = 1.00 g L).11. Calculation11.1 Calculate the absorp
30、tivity of the sample in the samemanner as that used for the standard (9.5).11.2 Calculate the weight percentage of sodium toluenesulfonate as follows:Sodium toluene sulfonate, weight % 5 a1/a2! 3100 (2)where:a1= absorptivity of the sample, anda2= absorptivity of the standard.12. Precision12.1 The pr
31、ecision of this method is as follows:Within-laboratory, % 0.085Between-laboratory, % 0.200These values were determined at the 0 to 3 % level.13. Keywords13.1 hydrotropes; sodium toluene sulfonate; ultraviolet ab-sorption4Eastman Organic Chemical No. 524 has been found satisfactory for thispurpose.D2
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