Annals of Occupational Hygiene Advance Access published online on October 4, 2009
Annals of Occupational Hygiene, doi:10.1093/annhyg/mep069
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Quantitative Plasma Biomarker Analysis in HDI Exposure Assessment
1 Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, CB #7431, Rosenau Hall, NC 27599, USA
2 Local Hazardous Waste Management Program, Public Health—Seattle & King County, Seattle, WA 98104, USA
* Author to whom correspondence should be addressed. Tel: +1-919-966-3826; fax: +1-919-966-7911; e-mail: leena_french{at}unc.edu
Quantification of amines in biological samples is important for evaluating occupational exposure to diisocyanates. In this study, we describe the quantification of 1,6-hexamethylene diamine (HDA) levels in hydrolyzed plasma of 46 spray painters applying 1,6-hexamethylene diisocyanate (HDI)-containing paint in vehicle repair shops collected during repeated visits to their workplace and their relationship with dermal and inhalation exposure to HDI monomer. HDA was detected in 76% of plasma samples, as heptafluorobutyryl derivatives, and the range of HDA concentrations was 
0.02–0.92 µg l–1. After log-transformation of the data, the correlation between plasma HDA levels and HDI inhalation exposure measured on the same workday was low (N = 108, r = 0.22, P = 0.026) compared with the correlation between plasma HDA levels and inhalation exposure occurring 
20 to 60 days before blood collection (N = 29, r = 0.57, P = 0.0014). The correlation between plasma HDA levels and HDI dermal exposure measured on the same workday, although statistically significant, was low (N = 108, r = 0.22, P = 0.040) while the correlation between HDA and dermal exposure occurring 20 to 60 days before blood collection was slightly improved (N = 29, r = 0.36, P = 0.053). We evaluated various workplace factors and controls (i.e. location, personal protective equipment use and paint booth type) as modifiers of plasma HDA levels. Workers using a downdraft-ventilated booth had significantly lower plasma HDA levels relative to semi-downdraft and crossdraft booth types (P = 0.0108); this trend was comparable to HDI inhalation and dermal exposure levels stratified by booth type. These findings indicate that HDA concentration in hydrolyzed plasma may be used as a biomarker of cumulative inhalation and dermal exposure to HDI and for investigating the effectiveness of exposure controls in the workplace.
biomarker • dermal exposure • 1,6-hexamethylene diamine (HDA) • 1,6-hexamethylene diisocyanate (HDI) • inhalation exposure • plasma
Received May 21, 2009; in final form September 2, 2009