Development, validation and characterization of an analytical method for the quantification of hydrolysable urinary metabolites and plasma protein adducts of 2,4- and 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate and 4,4'-methylenediphenyl diisocyanate.
Occupational exposure to diisocyanates within the plastic industry causes irritation and disorders in the airway. The aim of this study was to develop, validate and characterize a method for the determination of 2,4-toluenediamine (2,4-TDA), 2,6-toluenediamine (2,6-TDA), 1,5-diaminonaphthalene (1,5-NDA) and 4,4'-methylenedianiline (4,4'-MDA) in hydrolysed urine and plasma, and to study the correlation between the plasma and urinary levels of these potential biomarkers of 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), 1,5-naphthalene diisocyanate (1,5-NDI) and 4,4'-methylenediphenyl diisocyanate (4,4'-MDI), respectively. Samples were hydrolysed with 0.3 M NaOH at 100 degrees C for 24 h. The diamines were extracted, derivatized with pentafluoropropionic acid anhydride, and quantified by selected ion monitoring on gas chromatography-mass spectrometry. The repeatability and reproducibility of the method were 7-18% and 7-19%, respectively. Dialysis experiments showed that the metabolites of 2,4-TDI, 2,6-TDI, 1,5-NDI and 4,4'-MDI in plasma were exclusively protein adducts. No free diamines were found in urine, indicating that all diisocyanate-related metabolites were in a conjugated form. For each diisocyanate-related biomarker, there were strongly significant correlations (p<0.001) between individual levels of metabolites in plasma and urine, with Spearman's rank correlation coefficient (rs) values of 0.74-0.90. The methods presented here will be valuable for the development of biological monitoring methods for diisocyanates.
Sennbro
Carl Johan
CJ
Department of Occupational and Environmental Medicine, Institute of Laboratory Medicine, University Hospital, Lund, Sweden. carl-johan.sennbro@ymed.lu.se
Lindh
Christian H
CH
Tinnerberg
Håkan
H
Gustavsson
Cecilia
C
Littorin
Margareta
M
Welinder
Hans
H
Jönsson
Bo A G
BA
D015415:Biomarkers / Q000097:blood / Q000652:urine; D003959:Diamines / Q000097:blood / Q000652:urine; D005456:Fluorescent Dyes; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006841:Hydrocarbons, Aromatic / Q000032:analysis* / Q000378:metabolism; D006868:Hydrolysis; D017953:Isocyanates / Q000032:analysis* / Q000097:blood / Q000378:metabolism / Q000652:urine; D016273:Occupational Exposure / Q000032:analysis*; D010969:Plastics; D014051:Toluene 2,4-Diisocyanate / Q000097:blood / Q000652:urine; D001559:Benzhydryl Compounds
D015415:Biomarkers; D003959:Diamines; D005456:Fluorescent Dyes; D006841:Hydrocarbons, Aromatic; D017953:Isocyanates; D010969:Plastics; D014051:Toluene 2,4-Diisocyanate; C023446:1,5-naphthylene di-isocyanate; C026942:2,6-diisocyanatotoluene; C005969:4,4'-diphenylmethane diisocyanate; D001559:Benzhydryl Compounds