This test method covers the determination of ethylene oxide content in polyethoxylated nonionic surfactants. It can also be used for compounds containing propylene oxide or any compounds (glycols and glycol and polyglycol ethers and esters) which form unstable 1,2-diiodides on reaction with hydroiodic acid. The apparatus is comprised of the following: heat source which shall be an electric heater provided with a sliding rheostat or other means of heat control; flasks which shall be equipped with a standard ground-glass joint; condensers with standard joints; gas bubbler filled with dibutyl phthalate; buret; and pipet. The dual apparatus is designed to permit a sample and a blank to be run simultaneously. Reagent grade chemicals or reagents of sufficiently high purity including water, carbon dioxide or nitrogen, lubricant, dibutyl phthalate, glass beads, hydroiodic acid, hydrochloric acid, methanol, potassium dichromate, potassium iodide solution, sodium thiosulfate, and starch indicator solution shall be used in all tests. The ethylene oxide content shall be calculated from the amount of sodium thiosulfate solution required to titrate the sample and the blank, normality of sodium thiosulfate, and weight of the sample. Standard deviations for repeatability and reproducibility shall be estimated to determine the acceptability of the results.
1.1 This test method covers the determination of ethylene oxide in polyethoxylated nonionic surfactants. It can also be used for compounds containing propylene oxide or any compounds (glycols and glycol and polyglycol ethers and esters) which form unstable 1,2-diiodides on reaction with hydriodic acid.
Note 1: Compounds in which the oxyalkylene group is connected to a nitrogen cannot be entirely decomposed. This can be used to determine the percent of an ethoxylated surfactant in a mixture, if the ethylene oxide content of the ethoxylated surfactant is known.
Note 2: This method reports results as percent ethylene oxide. If this method is applied to unknown compounds or compositions, the analyst should be aware of the possible presence of material other than ethylene oxide.
Note 3: For use on built syndet compositions the organic active ingredient must be isolated in accordance with Test Method .
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior to usage.