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Development and application of a dichotomous vapor/aerosol sampler for HDI-derived total reactive isocyanate group.

Authors
Rando-RJ; Poovey-HG
Source
Am Ind Hyg Assoc J 1999 Nov/Dec; 60(6):737-746
NIOSHTIC No.
20031343
Abstract
A dichotomous vapor/aerosol sampler was developed for measurement of HDI (1,6-hexamethylene diisocyanate)-derived total reactive isocyanate group (TRIG). The sampler consisted of an impactor or cyclone inlet, followed by an annular diffusional denuder, and a glass-fiber filter backup. The denuder walls and backup filter were each coated with 20 mg tributylphosphate and 1 mg MAMA reagent (9-N-methylamino-methylanthracene). After collection, MAMA-derivatized isocyanates were desorbed from the sampler and determined by high-performance liquid chromatography with dual-wavelength ultraviolet absorbance and fluorescence detection. Test atmospheres of HDI vapor and of HDI/HDI-biuret aerosols were generated in the laboratory and sampled with the optimized dichotomous sampler. Vapor phase HDI was completely collected by the diffusional denuder. When a mixture of HDI-biuret and HDI (approximately 30 ppb) was nebulized and collected with the dichotomous sampler, approximately 78% of the HDI was in the vapor phase, whereas about 22% was associated with the aerosol fraction. The dichotomous sampler was then used to measure vapor and condensed phase TRIG in a paint spray booth during application of a polyurethane paint. Measured levels of TRIG during the spraying operation averaged 391 +/- 154 micrograms/m3. Concentrations of HDI monomer averaged only 14 +/- 6.5 micrograms/m3. HDI-biuret was the largest component of TRIG found in these samples and was completely in the condensed aerosol phase. In contrast, the majority of the HDI was in the vapor phase, but significant (15-26%) amounts were measured in the aerosol fraction of the paint overspray. Thus, significant partitioning of HDI between vapor and condensed phases was demonstrated in both the laboratory and field, even when its concentration was well below the vapor saturation point.
Keywords
Aerosol-sampling; Air-contamination; Air-sampling-equipment; Bronchial-asthma; Environmental-pollution; Pollutants; Respiratory-hypersensitivity; Paint-removers; Paint-thinners; Vapors; Aerosols; Isocyanates
Contact
Department of Environmental Health Sciences, SL29, School of Public Health and Tropical Medicine, Tulane Medical Center, 1430 Tulane Ave., New Orleans, LA 70112-2699
CODEN
AIHAAP
CAS No.
822-06-0; 108-19-0
Publication Date
19991101
Document Type
Journal Article
Funding Amount
209735
Funding Type
Grant
Fiscal Year
2000
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-02664
Issue of Publication
6
ISSN
0002-8894
Priority Area
Other Occupational Concerns; Grants-other
Source Name
American Industrial Hygiene Association Journal
State
ME; LA
Performing Organization
Tulane University of Louisiana, New Orleans, Louisiana
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