Sampling of Respirable Isocyanate Particles
2014 (English)In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 58, no 3, 340-354 p.Article in journal (Refereed) Published
An advanced design of a denuder impactor (DI) sampler has been developed for characterization of possible airborne isocyanate exposure in different particle size fractions. The sampler is equipped with 12 different parallel denuder tubes, 4 impaction stages with the cut-off values (d50) of: 9.5, 4, 2.5 and 1 µm, and an end filter that collects particles < 1 µm. All collecting parts were impregnated with di-n-butylamine DBA as the reagent in a mixture with acetic acid. The performance of the DI sampler was studied on a standard atmosphere containing gas and particulate isocyanates. The isocyanate atmosphere was generated by liquid permeation of 2,4-, 2,6-Toluene Diisocyanate (TDI), 1,6-Hexamethylene Diisocyanate (HDI) and Isophorone Diisocyanate (IPDI). 4,4’-Methylene Diphenyl Diisocyanate (MDI) particles were generated by heating of technical MDI and condensing the mixture of gas and particle-borne MDI in an atmosphere containing mixed salt particles. The study was performed in a 0.85 m3 environmental chamber with stainless steel walls. With the advancement of the DI sampler it is now possible to collect isocyanate particle samples for up to 320min. The performance of the DI sampler is essentially unaffected by the humidity. The DI sampler and the ASSET™ EZ4-NCO sampler (Sigma-Aldrich/Supelco, Bellefonte, PA, USA) gave similar results. Sample losses within the DI sampler are low. In the environmental chamber it was observed that the particle distribution may be affected by the humidity and ageing. A scanning mobility particle sizer (SMPS) was used to separate a flow of selected fractions containing MDI particles from mixed MDI and salt particles. The particle-size distribution had a maximum at about 300nm, but later in the environmental chamber 1 µm dominated. The distribution was very different as compared to with only NaCl or MDI present. The biological relevance for studying isocyanate nano particles is significant as these have the possibility to reach the lower airways where allergic reactions may occur. SMPS and isocyanate air sampling can be used for the investigation of isocyanate nano particles.
Place, publisher, year, edition, pages
2014. Vol. 58, no 3, 340-354 p.
aerosol, air sampling, DBA, denuder, impactor, isocyanate, respirable
Research subject Analytical Chemistry
IdentifiersURN: urn:nbn:se:su:diva-101552DOI: 10.1093/annhyg/met067ISI: 000333046700007OAI: oai:DiVA.org:su-101552DiVA: diva2:704126