Development of a sampling and analytical method for measuring the epoxy content of aerosols: II. Application of the method to epoxy-containing aerosols.
Herrick-RF; Smith-TJ; Ellenbecker-MJ
Am Ind Hyg Assoc J 1987 Sep; 48(9):773-779
A method for measuring the epoxy content of aerosols was described. Samples were collected in a midget impinger containing 10 milliliters of dimethylformamide (DMF). The epoxide content of the samples was determined by dissolving or suspending the sample in additional DMF, adding sufficient tetraethylammonium-bromide to achieve a 3:1 molar excess of bromide ion to the expected epoxide content and perchloric-acid to initiate the hydrobromination reaction of the epoxide moiety. The residual bromide concentration in the reaction mixture was measured by normal pulse polarography. The epoxide content of the sample was determined from the amount of bromide consumed in the hydrobromination reaction. Analyzing aerosols spiked with 0.5 to 1.9 milligrams of an epoxy resin yielded absolute recoveries of 0.955 to 0.978. The method was tested using aerosols containing mixtures of an epoxy resin and a curing agent, commercial resins, and two commercial epoxy surface coatings. The differences between the measured epoxy content and the epoxy content predicted from the weight of the nonvolatile aerosol did not exceed 25 percent. Recoveries were 76.1 to 110.5 percent. When collected samples were stored at room temperature or -20 degrees-C for 7 or 14 days, recoveries averaged 88.6 to 96.8 percent. The authors conclude that the method can measure the epoxy content of epoxy containing aerosols to within the OSHA/NIOSH criteria, 25 percent accuracy at the 95 percent confidence level.
NIOSH-Author; Analytical-methods; Epoxy-compounds; Epoxy-resins; Laboratory-testing; Electrochemical-analysis; Aerosol-sampling; Chemical-structure; Chemical-processing
Robert F. Herrick, National Institute for Occupational Safety and Health, Division of Surveillance, Hazard Evaluations and Field Studies, lndustrywide Studies Branch, Cincinnati, OH 45226
American Industrial Hygiene Association Journal