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Adsorption Efficiency of Respirator Filter Cartridges for Isocyanates
Stockholm University, Faculty of Science, Department of Analytical Chemistry.
Stockholm University, Faculty of Science, Department of Analytical Chemistry.
Stockholm University, Faculty of Science, Department of Analytical Chemistry.
Stockholm University, Faculty of Science, Department of Analytical Chemistry.
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2010 (English)In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 54, no 4, 377-390 p.Article in journal (Refereed) Published
Abstract [en]

In some industries, the temperature and the humidity will vary greatly between different work places, such as outdoor work in arctic or tropical climates. There is therefore a need to test respirator filters at conditions that simulate conditions that are relevant for the industries that they are used in. Filter cartridges were exposed to controlled atmospheres of varying isocyanate concentration, air humidity, and temperature in an exposure chamber. For isocyanic acid (ICA) and methyl isocyanate (MIC), the exposure concentrations were between 100 and 200 p.p.b., monitored using a proton transfer reaction mass spectrometer. ICA and MIC were generated by continuous thermal degradation of urea and dimethylurea. The breakthrough was studied by collecting air samples at the outlet of the filter cartridges using impinger flasks or dry samplers with di-n-butylamine as derivatization reagent for isocyanates followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. For hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), the exposure concentrations were between 4 and 20 p.p.b. and were generated by wet membrane permeation. To reveal the profile of adsorption in different layers of the respirator filters, representative samples from each of the layers were hydrolyzed. The hydrolysis products hexamethylene diamine and isophorone diamine were determined after derivatization with pentafluoropropionic anhydride (PFPA) followed by LC-MS/MS analysis. The two filter types studied efficiently absorbed both ICA and MIC. There was no trend of impaired performance throughout 48-h exposure tests. Even when the filters were exposed to high concentrations (similar to 200 p.p.b.) of ICA and MIC for 96 h, the isocyanates were efficiently absorbed with only a limited breakthrough. The majority of the HDI and IPDI (> 90%) were absorbed in the top layers of the absorbant, but HDI and IPDI penetrated farther down into the respirator filters during 120 h of exposure as compared to 16 h exposure.

Place, publisher, year, edition, pages
2010. Vol. 54, no 4, 377-390 p.
Keyword [en]
generation test atmosphere, hexamethylene diisocyanate, isocyanic acid, isophorone diisocyanate, methyl isocyanate, PPE, PTR-MS, respirator testing
National Category
Analytical Chemistry
Research subject
Analytical Chemistry
Identifiers
URN: urn:nbn:se:su:diva-50304DOI: 10.1093/annhyg/meq008ISI: 000278218200003OAI: oai:DiVA.org:su-50304DiVA: diva2:380797
Note

authorCount :10

Available from: 2010-12-22 Created: 2010-12-22 Last updated: 2017-12-11Bibliographically approved
In thesis
1. Isocyanates - methodology for gas and particle generation, sampling and detection
Open this publication in new window or tab >>Isocyanates - methodology for gas and particle generation, sampling and detection
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Isocyanates are mainly used in the industry for the production of polyurethane (PUR) plastics. Workers are at risk of being exposed during the manufacturing of PUR. During thermal degradation of PUR, isocyanates are released and workers involved in hot work such as fire-fighting, welding etc. may also be exposed.

Isocyanates are known to cause allergic diseases and are the most common cause of occupational asthma. Some of the isocyanates used are suspected human carcinogens. Exposure among workers occurs frequently.

Isocyanates are reactive unstable compounds that need to be converted to stabile derivatives immediately during sampling to avoid underestimation of the exposure. Di-n-ButylAmine (DBA) was used as derivatising reagent to form stable urea derivatives. The DBA derivatives were analysed using LC-MS/MS.

In this thesis a novel technology for the direct monitoring of isocyanates using a Proton Transfer Reaction Mass Spectrometry (PTR-MS) is presented. Advancement of technology for the generation of isocyanates in an environmental chamber, dry sampling, particle-size fractionated sampling and the testing of respirator filter cartridges are described.

The dry sampler was demonstrated to be robust and enabled sampling up to 32 h. Precise sampling without the need of field extraction was made possible.

The particle-size fractionated sampling efficiently separated gas-phase and respirable particle-borne isocyanates (< 4µm in diameter).

Two personal protective respirator filter cartridges were studied. No trend of impaired performance for mono-isocyanates throughout 48-h exposure tests was found.

The distribution patterns, in a steady-state tube-furnace oven, between gas phase and different particle-phase fractions of isocyanates produced in fires were investigated. The substantial degradation of a PVC-carpet containing PUR and a wood board with a MDI based binder resulted mainly in the formation of high levels of monoisocyanates.

Place, publisher, year, edition, pages
Stockholm: Department of Analytical Chemistry, Stockholm University, 2012. 107 p.
Keyword
Isocyanate, PUR, Dry sampler, PTR-MS, Transfer line, PPE, Environmental Chamber, Respirable Particles, Denuder Impactor, Aerosol, Particles, Impinger, air sampling, LC-MS, di-n-butylamine, DBA, ICA, MIC, HDI, TDI, IPDI, MDI, Occupational Exposure, Exposure, Occupational Health
National Category
Analytical Chemistry
Research subject
Analytical Chemistry
Identifiers
urn:nbn:se:su:diva-79501 (URN)978-91-7447-556-2 (ISBN)
Public defence
2012-10-05, Vita salen, Hässleholm Kulturhus, Vattugatan 18/Järnvägsgatan 23, Hässleholm, Hässleholm, 10:00 (English)
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Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 2: Submitted. Paper 5: Accepted.

Available from: 2012-09-13 Created: 2012-09-04 Last updated: 2014-03-17Bibliographically approved

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