US EPA

5750618 

Journal Article 

Simultaneous analysis of the di(2-ethylhexyl)phthalate metabolites 2-ethylhexanoic acid, 2-ethyl-3-hydroxyhexanoic acid and 2-ethyl-3-oxohexanoic acid in urine by gas chromatography–mass spectrometry 

Günther Wahl, H; Hong, Q; Stübe, D; Maier, ME; Häring, HU; Liebich, HM 

2001 

1 

Journal of Chromatography. Biomedical Applications
ISSN: 0378-4347 

ELSEVIER SCIENCE BV 

AMSTERDAM 

758 

2 

213-219 

English 

11486831 

10.1016/s0378-4347(01)00183-9 

WOS:000169712400011 

http://www.sciencedirect.com/science/article/pii/S0378434701001839
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A gas chromatographic–mass spectrometric method was developed for the quantitative analysis of the three Di(2-ethylhexyl)phthalate (DEHP) metabolites, 2-ethylhexanoic acid, 2-ethyl-3-hydroxyhexanoic acid and 2-ethyl-3-oxohexanoic acid in urine. After oximation with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride and sample clean-up with Chromosorb P filled glass tubes, all three organic acids were converted to their tert.-butyldimethylsilyl derivatives. Quantitation was done with trans-cinnamic acid as internal standard and GC–MS analysis in the selected ion monitoring mode (SIM). Calibration curves for all three acids in the range from 20 to 1000 μg/l showed correlation coefficients from 0.9972 to 0.9986. The relative standard deviation (RSD) values determined in the observed concentration range were between 1.3 and 8.9% for all three acids. Here we report for the first time the identification of 2-ethyl-3-hydroxyhexanoic acid and 2-ethyl-3-oxohexanoic acid in human urine next to the known DEHP metabolite 2-ethylhexanoic acid. In 28 urine samples from healthy persons we found all three acids with mean concentrations of 56.1±13.5 μg/l for 2-ethylhexanoic acid, 104.8± 80.6 μg/l for 2-ethyl-3-hydroxyhexanoic acid and 482.2± 389.5 μg/l for 2-ethyl-3-oxohexanoic acid. 

Di(2-ethylhexyl)phthalate; 2-Ethylhexanoic acid; 2-Ethyl-3-hydroxyhexanoic acid; 2-Ethyl-3-oxohexanoic acid