1、Designation: E299 17E299 17aStandard Test Method forTrace Amounts of Peroxides In Organic Solvents1This standard is issued under the fixed designation E299; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test method2,3 covers organic solvents c
3、ontaining active oxygen in the range from 5 to 80 g/g (ppm) or higher. Byusing a special reaction-absorption cell, the test method can be extended to cover the range from 0 to 5 ppm. The test method canbe used to determine numerous peroxide classes of varying reactivity such as hydroperoxides, diacy
4、l peroxides, diaroyl peroxides,peresters, and ketone peroxides. The stable di-tert-alkyl peroxides do not react under the conditions of analysis.1.2 Solvents that can be analyzed successfully include saturated and aromatic hydrocarbons, alcohols, ethers, ketones, andesters. In addition, the test met
5、hod is applicable to olefinic solvents and to certain compounds that contain , and conjugatedunsaturation. Solid samples that are soluble in the acetic acid-chloroform solvent also can be analyzed.1.3 Review the current Safety Data Sheets (SDS) for detailed information concerning toxicity, first aid
6、 practices, and safetyprecautions.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.5 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of theuser of this
7、 standard to establish appropriate safety and health practices and determine the applicability of regulatory limitationsprior to use.1.5 Review the current Safety Data Sheets (SDS) for detailed information concerning toxicity, first aid practices, and safetyprecautions.1.6 This international standar
8、d was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referen
9、ced Documents2.1 ASTM Standards:4D1193 Specification for Reagent WaterD6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related MaterialsE180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemi
10、cals(Withdrawn 2009)53. Summary of Test Method3.1 A sample is dissolved in a mixture of acetic acid and chloroform. The solution is deaerated and potassium iodide reagentsolution is added. The mixture is allowed to react in the dark for 1 h, thereby releasing an equivalent amount of iodine. Theabsor
11、bance of the solution is measured at 470 nm and the amount of active oxygen present in the sample is determined by referenceto a calibration curve prepared from iodine.1 This test method is under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Rela
12、ted Chemicals and is the directresponsibility of Subcommittee D16.15 on Industrial and Specialty General Standards.Current edition approved Feb. 1, 2017July 1, 2017. Published February 2017July 2017. Originally approved in 1966. Last previous edition approved in 20082017 asE299 08.E299 17. DOI: 10.1
13、520/E0299-17.10.1520/E0299-17a.2 Banerjee, D. K., and Budke, C. C., Analytical Chemistry, ANCHAM, Vol 36, 1964, pp. 792796.3 Banerjee, D. K., and Budke, C. C., Analytical Chemistry, ANCHAM, Vol 36, 1964, pp. 23672368.4 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM
14、 Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.5 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only
15、 to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versio
16、nof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 For samples containing 0 to 5 g/g (pp
17、m) 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 at 410 nm to increase the sensitivity.4. Significance and Use4.1 Dilute solutions of peroxides in various organic solvents freque
18、ntly are used as catalysts or reaction initiators. Peroxides alsocan be formed through autoxidation in certain classes of compounds including ethers, acetals, dienes, and alkylaromatichydrocarbons and present a potential safety hazard. This test method provides a procedure for determining the peroxi
19、de or activeoxygen level.5. Interferences5.1 Oxidizing or reducing substances present in the sample will interfere. Colored solutions can be analyzed if an absorbancecorrection is made.6. Apparatus6.1 SpectrophotometerBeckman Model DU or equivalent with matched 1-cm cells.6.2 Special Reaction-Absorp
20、tion Cell (Fig. 1)When this cell is used, the regular Beckman cell carriage shall be replaced withthe attachment provided for measuring the absorbance in test tubes.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that al
21、lreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lesseni
22、ng the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean Type II or Type III reagentwater conforming to Specification D1193.7.3 Acetic Acid-Chloroform Solvent (2 + 1)Mix 2 volumes of acetic acid with 1 volume of chloroform.7.
23、4 Acetic Acid-Chloroform Solvent (Containing Approximately 4 % Water)Add 40 mL of water to 1 L of solvent preparedas described in 7.3.7.5 Iodine.7.6 Nitrogen Cylinder.6 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the test
24、ing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.FIG. 1 Absorption Cell for Low-Active OxygenE2
25、99 17a27.7 Potassium Iodide Solution (50 %)Dissolve 20 g of potassium iodide (KI) in 20 mL of de-aerated water. This reagentshould be freshly prepared just prior to use.7.8 Water, De-aeratedPass nitrogen through distilled water for several minutes prior to use.8. Procedure8.1 High Range0 to 400 g of
26、 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 volumetric flask. Thissolution contains 1.27 mg of iodine/mL, which is equivalent to 80.0 g of active oxygen/mL.8.1.1.2 Transfer 0, 1, 2, 3, 4
27、, and 5-mL aliquots of this solution to 25-mL volumetric flasks and dilute each to volume with theacetic acid-chloroform solvent. Mix thoroughly.8.1.1.3 Using a hypodermic needle or glass capillary, sparge the solution with nitrogen for 1 to 1.5 min, add 1 mL of freshlyprepared KI solution, and cont
28、inue 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 the absorbance of each standard against micrograms of active oxygen per25 mL.8.1.2 Analysis o
29、f Sample:8.1.2.1 Transfer a sample containing up to 400 g of active oxygen to a 25-mLvolumetric flask and dilute to volume with aceticacid-chloroform solvent (2 + 1) (Note 1). Mix thoroughly.NOTE 1A sample volume up to 15 mL may be used provided it is miscible with the amount of acetic acid-chlorofo
30、rm solvent required to dilute thesample 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 the nitrogenflow for an additional 1 min.8.1.2.3 Stopper, mix well, and allow the solution to stand in the dark for 1 h.NOTE 2Very react
31、ive peroxides react within less than 10 min, while less reactive peroxides require up to 1 h for complete reaction.Ageneral reactiontime for 1 h is therefore specified.8.1.2.4 Measure the absorbance of the solution at 470 nm using 1-cm cells and a water reference.NOTE 3Depending on the amount and ty
32、pe of sample present, some precipitation of KI may occur. However, the KI crystals readily settle to thebottom in absorbance measurement.8.1.2.5 Subtract the absorbance of a blank carried through the entire procedure, and obtain the micrograms of active oxygenpresent in the sample by reference to th
33、e calibration curve.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 a 10-mL aliquotto another 100-mL volumetric flask and dilute to volume with acetic acid-chlo
34、roform solvent. This solution contains 63.4 g ofiodine/mL which is equivalent to 4.0 g of active oxygen/mL.8.2.1.2 Transfer 0, 1, 3, 5, 8, and 10-mL aliquots to 25-mL volumetric flasks and dilute to volume with the aceticacid-chloroform solvent containing 4 % water. Mix well.8.2.1.3 Transfer a porti
35、on of each standard to the special absorption cell (Fig. 1).Admit a flow of nitrogen through the side armand purge the solution for 3 min.8.2.1.4 Add 5 drops of freshly prepared de-aerated KI solution and replace the stopper loosely. Continue purging with nitrogenfor an additional 3 min.8.2.1.5 Tigh
36、ten the stopper and close the stopcock on the inlet tube so that the solution is under a slightly positive nitrogenpressure.8.2.1.6 The absorption tubes shall be matched and provided with a glass ear for reproducible positioning before absorbancemeasurements are made. Insert the tube into the cell c
37、arriage and rotate until the glass ear contacts the side of the tube holder.Measure the absorbance of the solution at 410 nm against water contained in another matched absorption tube.8.2.1.7 Subtract the absorbance of the blank and plot absorbance against micrograms of active oxygen per 25 mL.8.2.2
38、 Analysis of Sample:8.2.2.1 Transfer a 5.00-mLsample to a 25-mLvolumetric flask and dilute to volume with acetic acid-chloroform solvent (2 + 1)containing 4 % water. Mix well.8.2.2.2 Transfer a portion of the solution to the special absorption cell and develop the color as described in 8.2.1.3, 8.2.
39、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 nm against water contained in the other matched absorption tube.E299 17a38.2.2.5 Subtract the absorbance obtained for a blank carried through the entire procedure, and obtain t
40、he micrograms of activeoxygen present in the sample by reference to the calibration curve.9. Calculation9.1 Calculate the active oxygen content of the sample as follows:active oxygen,g/gppm!5 ABC (1)where:A = active oxygen found, g,B = sample used, mL, andC = density, g/mL.9.2 If a specific peroxide
41、 is known to be present, convert the micrograms per gram (parts per million) of active oxygen toperoxide by using the appropriate conversion factor.Peroxide X,g/gppm!5active oxygen in sample,g/gppm!3F (2)where F = conversion factor for peroxide X.9.2.1 Conversion factors for some common peroxides ar
42、e as follows:Cumene hydroperoxide 9.5125Benzoyl peroxide 15.1400t-butyl hydroperoxide 5.6328Lauroyle peroxide 24.915010. Report10.1 High RangeReport the concentration of the peroxide to the nearest 1 g/g (ppm).10.2 Low RangeReport the concentration of the peroxide to the nearest 0.1 g/g (ppm).11. Pr
43、ecision and Bias711.1 PrecisionHigh RangeThe following criteria shall be used for judging the acceptability of results (Note 4):11.1.1 Repeatability (Single Analyst)The standard deviation for a single determination has been estimated to be 0.7 g/g(ppm) at 36 df. The 95 % limit for the difference bet
44、ween two 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 by the same analyst on different days, has been estimated to be 2.9 g/g (ppm) at 14 df. The 95 %limit for t
45、he difference between two such averages is 8.1 g/g (ppm).11.1.3 Reproducibility (Multilaboratory)The standard deviation of results, each the average of duplicates, obtained byanalysts in different laboratories has been estimated to be 4.6 g/g (ppm) at 5 df. The 95 % limit for the difference between
46、twosuch averages is 13 g/g (ppm).NOTE 4The above precision estimates are based on an interlaboratory study on three samples containing 30 to 90 g/g (ppm) of active oxygen. Oneanalyst in each of six laboratories performed duplicate determinations and repeated one day later, for a total of 72 determin
47、ations. Practice E180 was usedin developing these precision estimates.11.2 BiasThe bias of this test method has not been determined due to the lack of suitable reference materials or methodology.11.3 PrecisionLow RangeThe following criteria shall be used for judging the acceptability of results (Not
48、e 5):11.3.1 Repeatability (Single Analyst)The standard deviation for a single determination has been estimated to be 0.07 g/g(ppm) at 24 df. The 95 % limit for the difference between two such determinations is 0.2 g/g (ppm).11.3.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)The
49、 standard deviation of results, each theaverage of duplicates, obtained by the same analyst on different days, has been estimated to be 0.11 g/g (ppm) at 13 df. The 95 %limit for the difference between two such averages is 0.31 g/g (ppm).11.3.3 Reproducibility (Multilaboratory)The standard deviation of results, each the average of duplicates, obtained byanalysts in different laboratories has been estimated to be 0.49 g/g (ppm) at 4 df. The 95 % limit for the difference between twosuch averages is 1.4 g/g (ppm).NOTE
