科研之友
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摘要
Di-isodecyl phthalate (DiDP), primarily used as a plasticiser, is a mixture of isomers with predominantly ten-carbon branched side chains. Assessment of DiDP exposure has not been conducted before because adequate biomarkers were lacking. In 129 adult volunteers with no known exposure to DiDP, the urinary concentrations of three oxidative metabolites of DiDP: monocarboxyisononyl phthalate (MCiNP), monooxoisodecyl phthalate (MOMP) and monohydroxyisoclecyl phthalate (MHiDP), previously identified in DiDP-dosed rats, were estimated by solid-phase extraction coupled to high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using the respective oxidative metabolites of di(2-ethylhexyl)phthalate since authentic standards of the DiDP oxidative metabolites were unavailable. Interestingly, the hydrolytic monoester of DiDP, monoisoclecyl phthalate (MiDP), was not detected in any of the samples, while MCiNP, MHiDP and MOMP were detected in 98%, 96% and 85%, respectively, of the samples tested. MCiNP was excreted predominantly in its free form, whereas MOMP was excreted as its glucuronide. MCiNP, MHiDP and MOMP eluted as clusters of multiple peaks from the HPLC column probably due to the presence of numerous structurally similar isomers present in commercial DiDP formulations. The urinary concentrations of these oxidative metabolites correlated significantly (p < 0.0001) with each other, thus confirming a common precursor. The urinary concentrations of these DiDP oxidative metabolites also correlated significantly (p < 0.0001) with oxidative metabolites of di-isononyl phthalate (DiNP) suggesting the potential presence of DiNP isomers in commercial DiDP or simultaneous use of DiDP and DiNP in consumer products. The concentrations presented are semiquantitative estimates and should be interpreted cautiously. Nevertheless, the higher frequency of detection and higher urinary concentrations of MCiNP, MHiDP and MOMP than of MOP suggest that these oxidative metabolites are better biomarkers for DiDP exposure assessment than MiDP These data also suggest that unless oxidative metabolites are measured, the prevalence of exposure to DiDP will probably be underestimated.
- 出版日期2007-4
