1、Designation: E 299 08Standard Test Method forTrace Amounts of Peroxides In Organic Solvents1This standard is issued under the fixed designation E 299; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method2,3covers organic solvents containingactive oxygen in the range from 5 to 80 g/g (ppm) or higher.By using a special reac
3、tion-absorption cell, the test method canbe extended to cover the range from 0 to 5 ppm. The testmethod can be used to determine numerous peroxide classes ofvarying reactivity such as hydroperoxides, diacyl peroxides,diaroyl peroxides, peresters, and ketone peroxides. The stabledi-tert-alkyl peroxid
4、es do not react under the conditions ofanalysis.1.2 Solvents that can be analyzed successfully includesaturated and aromatic hydrocarbons, alcohols, ethers, ketones,and esters. In addition, the test method is applicable to olefinicsolvents and to certain compounds that contain a, b, andconjugated un
5、saturation. Solid samples that are soluble in theacetic acid-chloroform solvent also can be analyzed.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address the safetyconcerns, if any, asso
6、ciated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.1.5 Review the current Material Safety Data Sheets (MSDS)for detailed information concerning toxicity, f
7、irst aid practices,and safety precautions.2. Referenced Documents2.1 ASTM Standards:4D 1193 Specification for Reagent WaterE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals3. Summary of Test Method3.1 A sample is dissolved in
8、a mixture of acetic acid andchloroform. The solution is deaerated and potassium iodidereagent solution is added. The mixture is allowed to react in thedark for 1 h, thereby releasing an equivalent amount of iodine.The absorbance of the solution is measured at 470 nm and theamount of active oxygen pr
9、esent in the sample is determinedby reference to a calibration curve prepared from iodine.3.2 For samples containing 0 to 5 g/g (ppm) active oxygen,a special reaction-absorption cell is employed. The sample isde-aerated and the reaction is carried out within the cell.Absorbance measurements are made
10、 at 410 nm to increase thesensitivity.4. Significance and Use4.1 Dilute solutions of peroxides in various organic solventsfrequently are used as catalysts or reaction initiators. Peroxidesalso can be formed through autoxidation in certain classes ofcompounds including ethers, acetals, dienes, and al
11、kylaromatichydrocarbons and present a potential safety hazard. This testmethod provides a procedure for determining the peroxide oractive oxygen level.5. Interferences5.1 Oxidizing or reducing substances present in the samplewill interfere. Colored solutions can be analyzed if an absor-bance correct
12、ion is made.6. Apparatus6.1 SpectrophotometerBeckman Model DU or equivalentwith matched 1-cm cells.6.2 Special Reaction-Absorption Cell (Fig. 1)When thiscell is used, the regular Beckman cell carriage shall be replacedwith the attachment provided for measuring the absorbance intest tubes.1This test
13、method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and is the direct responsibility of SubcommitteeE15.01 on General Standards.Current edition approved April 1, 2008. Published May 2008. Originallyapproved in 1966. Last previous edition approved in 2002 as E
14、299 97(2002).2Banerjee, D. K., and Budke, C. C., Analytical Chemistry , ANCHAM, Vol 36,1964, pp. 792796.3Banerjee, D. K., and Budke, C. C., Analytical Chemistry , ANCHAM, Vol 36,1964, pp. 23672368.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service a
15、t serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-295
16、9, United States.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are
17、 available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II or Type IIIr
18、eagent water conforming to Specification D 1193.7.3 Acetic Acid-Chloroform Solvent (2 + 1)Mix 2 vol-umes of acetic acid with 1 volume of chloroform.7.4 Acetic Acid-Chloroform Solvent (Containing Approxi-mately 4% Water)Add 40 mL of water to 1 L of solventprepared as described in 7.3.7.5 Iodine.7.6 N
19、itrogen Cylinder.7.7 Potassium Iodide Solution (50 %)Dissolve 20 g ofpotassium iodide (KI) in 20 mL of de-aerated water. Thisreagent should be freshly prepared just prior to use.7.8 Water, De-aeratedPass nitrogen through distilled wa-ter for several minutes prior to use.8. Procedure8.1 High Range0 t
20、o 400 g of Active Oxygen:8.1.1 Preparation of Calibration Curve:8.1.1.1 Dissolve 0.1270 g of iodine in acetic acid-chloroform solvent (2 + 1) and dilute to 100 mL in a volumet-ric flask. This solution contains 1.27 mg of iodine/mL, whichis equivalent to 80.0 g of active oxygen/mL.8.1.1.2 Transfer 0,
21、 1, 2, 3, 4, and 5-mL aliquots of thissolution to 25-mL volumetric flasks and dilute each to volumewith the acetic acid-chloroform solvent. Mix thoroughly.8.1.1.3 Using a hypodermic needle or glass capillary, spargethe solution with nitrogen for 1 to 1.5 min, add 1 mL of freshlyprepared KI solution,
22、 and continue the nitrogen flow for 1 min.Stopper and mix well.8.1.1.4 Measure the absorbance of each solution at 470 nm,using 1-cm cells and a water reference.8.1.1.5 Subtract the absorbance of the blank and plot theabsorbance of each standard against micrograms of activeoxygen per 25 mL.8.1.2 Anal
23、ysis of Sample:8.1.2.1 Transfer a sample containing up to 400 g of activeoxygen to a 25-mL volumetric flask and dilute to volume withacetic acid-chloroform solvent (2 + 1) (Note 1). Mix thor-oughly.NOTE 1A sample volume up to 15 mL may be used provided it ismiscible with the amount of acetic acid-ch
24、loroform solvent required todilute the sample to 25 mL.8.1.2.2 Sparge the solution with nitrogen for 1 to 1.5 min,add 1 mL of freshly prepared KI solution, and continue thenitrogen flow for an additional 1 min.8.1.2.3 Stopper, mix well, and allow the solution to stand inthe dark for 1 h.NOTE 2Very r
25、eactive peroxides react within less than 10 min, whileless reactive peroxides require up to 1 h for complete reaction. A generalreaction time for1histherefore specified.8.1.2.4 Measure the absorbance of the solution at 470 nmusing 1-cm cells and a water reference.NOTE 3Depending on the amount and ty
26、pe of sample present, someprecipitation of KI may occur. However, the KI crystals readily settle tothe bottom in absorbance measurement.8.1.2.5 Subtract the absorbance of a blank carried throughthe entire procedure, and obtain the micrograms of activeoxygen present in the sample by reference to the
27、calibrationcurve.8.2 Low Range0 to 40 g of Active Oxygen:8.2.1 Preparation of Calibration Curve:8.2.1.1 Dissolve 0.0634 g of iodine in acetic acid-chloroform solvent (2 + 1) and dilute to 100 mL. Transfer a10-mLaliquot to another 100-mLvolumetric flask and dilute tovolume with acetic acid-chloroform
28、 solvent. This solutioncontains 63.4 g of iodine/mL which is equivalent to 4.0 g ofactive oxygen/mL.8.2.1.2 Transfer 0, 1, 3, 5, 8, and 10-mL aliquots to 25-mLvolumetric flasks and dilute to volume with the acetic acid-chloroform solvent containing 4% water. Mix well.8.2.1.3 Transfer a portion of ea
29、ch standard to the specialabsorption cell (Fig. 1). Admit a flow of nitrogen through theside arm and purge the solution for 3 min.8.2.1.4 Add 5 drops of freshly prepared de-aerated KIsolution and replace the stopper loosely. Continue purging withnitrogen for an additional 3 min.5Reagent Chemicals, A
30、merican Chemical Society Specifications , AmericanChemical 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 Formu
31、lary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Absorption Cell for Low-Active OxygenE2990828.2.1.5 Tighten the stopper and close the stopcock on theinlet tube so that the solution is under a slightly positivenitrogen pressure.8.2.1.6 The absorption tubes shall be matched and p
32、rovidedwith a glass ear for reproducible positioning before absorbancemeasurements are made. Insert the tube into the cell carriageand rotate until the glass ear contacts the side of the tubeholder. Measure the absorbance of the solution at 410 nmagainst water contained in another matched absorption
33、 tube.8.2.1.7 Subtract the absorbance of the blank and plot absor-bance against micrograms of active oxygen per 25 mL.8.2.2 Analysis of Sample:8.2.2.1 Transfer a 5.00-mL sample to a 25-mL volumetricflask and dilute to volume with acetic acid-chloroform solvent(2 + 1) containing 4% water. Mix well.8.
34、2.2.2 Transfer a portion of the solution to the specialabsorption cell and develop the color as described in 8.2.1.3,8.2.1.4, and 8.2.1.5.8.2.2.3 Allow the sample to stand in the dark for 1 h.8.2.2.4 Measure the absorbance of the solution at 410 nmagainst water contained in the other matched absorpt
35、ion tube.8.2.2.5 Subtract the absorbance obtained for a blank carriedthrough the entire procedure, and obtain the micrograms ofactive oxygen present in the sample by reference to thecalibration curve.9. Calculation9.1 Calculate the active oxygen content of the sample asfollows:active oxygen, g/g ppm
36、!5ABC(1)where:A = active oxygen found, g,B = sample used, mL, andC = density, g/mL.9.2 If a specific peroxide is known to be present, convert themicrograms per gram (parts per million) of active oxygen toperoxide by using the appropriate conversion factor.Peroxide X, g/g ppm!5active oxygen in sample
37、, g/g ppm!3F(2)where F = conversion factor for peroxide X.9.2.1 Conversion factors for some common peroxides are asfollows:Cumene hydroperoxide 9.5125Benzoyl peroxide 15.1400t-butyl hydroperoxide 5.6328Lauroyle peroxide 24.915010. Report10.1 High RangeReport the concentration of the peroxideto the n
38、earest 1 g/g (ppm).10.2 Low RangeReport the concentration of the peroxideto the nearest 0.1 g/g (ppm).11. Precision and Bias611.1 PrecisionHigh RangeThe following criteria shallbe used for judging the acceptability of results (Note 4):11.1.1 Repeatability (Single Analyst)The standard devia-tion for
39、a single determination has been estimated to be 0.7g/g (ppm) at 36 df. The 95 % limit for the difference betweentwo such determinations is 2 g/g (ppm) .11.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)The standard deviation of results, each theaverage of duplicates, obtained
40、by the same analyst on differentdays, has been estimated to be 2.9 g/g (ppm) at 14 df. The95 % limit for the difference between two such averages is 8.1g/g (ppm).11.1.3 Reproducibility (Multilaboratory)The standard de-viation of results, each the average of duplicates, obtained byanalysts in differe
41、nt laboratories has been estimated to be 4.6g/g (ppm) at 5 df. The 95 % limit for the difference betweentwo such averages is 13 g/g (ppm).NOTE 4The above precision estimates are based on an interlaboratorystudy on three samples containing 30 to 90 g/g (ppm) of active oxygen.One analyst in each of si
42、x laboratories performed duplicate determinationsand repeated one day later, for a total of 72 determinations. Practice E 180was used in developing these precision estimates.11.2 BiasThe bias of this test method has not beendetermined due to the lack of suitable reference materials ormethodology.11.
43、3 PrecisionLow RangeThe following criteria shallbe used for judging the acceptability of results (Note 5):11.3.1 Repeatability (Single Analyst)The standard devia-tion for a single determination has been estimated to be 0.07g/g (ppm) at 24 df. The 95 % limit for the difference betweentwo such determi
44、nations is 0.2 g/g (ppm).11.3.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)The standard deviation of results, each theaverage of duplicates, obtained by the same analyst on differentdays, has been estimated to be 0.11 g/g (ppm) at 13 df. The95 % limit for the difference betwee
45、n two such averages is 0.31g/g (ppm).11.3.3 Reproducibility (Multilaboratory)The standard de-viation of results, each the average of duplicates, obtained byanalysts in different laboratories has been estimated to be 0.49g/g (ppm) at 4 df. The 95 % limit for the difference betweentwo such averages is
46、 1.4 g/g (ppm).NOTE 5The above precision estimates are based on an interlaboratorystudy on three samples containing 3 to 10 g/g (ppm) of active oxygen.One analyst in each of five laboratories performed duplicate determina-tions and repeated one day later, for a total of 60 determinations. PracticeE
47、180 was used in developing these precision estimates.11.4 BiasThe bias of this test method has not beendetermined due to the lack of suitable reference materials ormethodology.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: E15
48、1002.E29908312. Keywords12.1 assay; organic; peroxides; spectrophotometricSUMMARY OF CHANGESSubcommittee E15.01 has identified the location of selected changes to this standard since the last issue(E 299-97(2002) that may impact the use of this standard.(1) Updated units of measure to comply with th
49、e InternationalSystem of Units (SI).(2) Added numbered paragraph in Scope stating that the SIunits are to be considered standard.(3) Deleted (Formerly called Repeatabiltiy) from Precisionsection.(4) Added Summary of Changes section.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights
