Evaluation of a Coated Filter Sampling Method for the Determination of Isocyanate Concentrations in Air.
NIOSH 1987 Apr:31 pages
An alternative sampling device was evaluated for the determination of isocyanates in air. Diphenylmethane and 1-(2- methoxyphenyl)piperazine were used to coat a glass fiber filter. The piperazine reacted with aromatic and aliphatic isocyanates, forming ureas. High pressure liquid chromatography was used to analyze these ureas with electrochemical detection. The mixing of the isocyanate aerosol with the reagent was facilitated by the diphenylmethane. In filter samples stored for 2 to 3 weeks, the ureas proved stable. The shelf life of the coated filter was 2 months. 2,4-Toluene-diisocyanate (584849) had detectable limits of 18.7 micrograms/cubic meter (microg/m3) and 4,4'-methylenediphenyl- isocyanate (101688) had a detection limit of 15.7microg/m3 in a 50 liter sample volume. When compared with the results obtained using a reference impinger method in laboratory sampling, the isocyanate air concentrations recorded from the coated filter method were higher. When tested in the field, air concentrations determined from the impinger samplers for more than 50 percent of the sample pairs were higher than those obtained by the filter sample method. The author concludes that this coated filter method was not reliable enough to be used for determining isocyanate aerosol concentrations in the atmosphere of a work environment.
NIOSH-Author; Air-sampling-techniques; Aerosol-sampling; Isocyanates; Sampling-methods; Filtration; Chemical-industry-workers;
NTIS Accession No.
Division of Physical Sciences and Engineering, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, 31 pages, 14 references