title: Determination of isocyanates in air using 1-(2-methoxyphenyl)piperazine-impregnated filters: long-term sampling performance and field comparison with impingers with dibutylamine.
abstract: Isocyanates may be harmful to workers and methods for monitoring air exposure in the field are necessary. The main aim of this study was to study the field performance of a method using 1-(2-methoxyphenyl)piperazine (2MP)-impregnated filters, by side-by-side comparison of long-term sampling with consecutive short-term samplings and also by short-term comparisons with other methods. Apart from using 2MP-impregnated filters, air monitoring was also performed by a modified 2MP method (FINMP) and by an impinger method using dibutylamine (DBA), which was the reference method. For short-term sampling the compared methods performed equally well for 2,6-toluenediisocyanate (2,6-TDI) and for isocyanic acid. For 2,4-toluenediisocyanate (2,4-TDI), the DBA method gave approximately 10% higher results according to linear regression than the 2MP method and for phenyl isocyanate, the DBA method gave significantly higher results than both the 2MP and FINMP methods. During long-term sampling (2-4 h) of TDI with the 2MP method, significantly lower levels were found compared with parallel sampling with consecutive short-term samplings. A time-dependent correction factor for long-term sampling was calculated to be 1.7 for 2,4-TDI and 1.5 for 2,6-TDI for 4 h sampling. The long-term sampling performance for other isocyanates was not studied. In conclusion, short-term monitoring shows that the 2MP method slightly underestimates the true air concentration for some of the isocyanates studied, but the error is relatively small considering the variation in exposure. For long-term monitoring the 2MP method can be applied for TDI but, since the method underestimates the concentrations, a correction factor is needed which needs to be corroborated further.
authors.affiliation: Department of Occupational and Environmental Medicine, University Hospital, SE-221 85 Lund, Sweden.
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Sennbro
authors.forename: Jenny
authors.initials: J
authors.lastname: Ekman
authors.forename: Christian H
authors.initials: CH
authors.lastname: Lindh
authors.forename: Hans
authors.initials: H
authors.lastname: Welinder
authors.forename: Bo A G
authors.initials: BA
authors.lastname: Jönsson
authors.forename: Håkan
authors.initials: H
authors.lastname: Tinnerberg
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis; D002082:Butylamines; D004784:Environmental Monitoring / Q000379:methods; D005374:Filtration / Q000379:methods; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis; D017953:Isocyanates / Q000032:analysis*; D008669:Metallurgy; D016273:Occupational Exposure / Q000032:analysis*; D010879:Piperazines
chemical_list: D000395:Air Pollutants, Occupational; D002082:Butylamines; D017953:Isocyanates; D010879:Piperazines; C045274:dibutylamine; C040083:1-(2-methoxyphenyl)piperazine