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Methods development for sampling and analysis of chlorine, chlorine dioxide, bromine, and iodine.

Dillon HK

Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Contract 210-80-0067, 1983 Apr; :1-27

00134748

Air sampling and analytical methods for the monitoring of chlorine (7782505), chlorine-dioxide (10049044), bromine (7726956), and iodine (7553562) were developed. Among the solid sorbents screened for ability to react with chlorine vapor in a gas/solid reaction, diphenylamine, N-vinylcarbazole, m-aminophenol, sodium- sulfamate/sodium-hydroxide, and potassium-iodide displayed significant degrees of reactivity. However, none of the substrates provided an entirely suitable collection medium. A suitable solid sorbent for chlorine-dioxide was not found. Instead, a sampling and analysis method for chlorine-dioxide based on an impinger sampler containing the spectrophotometric reagent chlorophenol-red was tested. The test method performed satisfactorily except that no accurate, convenient means of standardizing the reagent solution appeared to exist. Precision, sampling capacity, storability, specificity, sensitivity, and analyte slippage rates associated with the test method were satisfactory for validation. Calculations of the uncertainty in quantities of chlorine-dioxide predicted from measured absorbances of exposed impinger solutions indicated that 95 percent of the time, approximately 4 micrograms of chlorine-dioxide could be determined with an estimated error of about 10 percent for six replicate determinations. However, the method exhibited a systematic bias relative to the reference method, which was based on dual pH iodometry, which could not be solved. Attempts to quantify bromine based on the reaction of bromine with silver membrane filters were not successful. Attempts to determine extracted bromides ion by ion chromatography were thwarted by interference from contaminants in candidate extraction media and by other factors. A method was validated for iodine in the concentration of method, iodine was sorbed onto alkali treated charcoal to produce the iodide ion. The iodide ion was then sorbed with a 10 millimolar solution of sodium-carbonate and determined by ion chromatography. The method yielded an iodine concentration that was within 25 percent of the true result 95 percent of the time.

NIOSH-Contract; Environmental-exposure; Industrial-exposures; Air-quality-control; Sampling-equipment; Air-sampling; Air-sampling-techniques; Chemical-analysis; Contract-210-80-0067

7782-50-5; 10049-04-4; 7726-95-6; 7553-56-2

19830401

Final Contract Report

Contract

1983

PB83-246363

A03

Contract-210-80-0067

National Institute for Occupational Safety and Health

AL; OH

Southern Research Institute