Abstract:

A method has been developed for the analysis of seven metabolites of phthalates in human urine by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The urine samples were hydrolyzed with glucuronidase followed by purification with solid-phase extraction (SPE) cartridges. Both 0.1% formic acid in water (v/v) and 0.1% formic acid in acetonitrile were used as the mobile phases in a gradient mode. The chromatographic separation was achieved on a phenyl column. Mass detection was then conducted by electrospray ionization in negative ion mode and multiple reaction monitoring mode. The components were quantified by stable isotope-labelled (¹³C-) phthalate monoester internal standards. The calibration curves of the seven phthalates metabolites showed good linear relationships in the range of 0.2-200.0 μg/L (r>0.99976). The recoveries at three levels were from 88.8% to 108.9% with relative standard deviations no more than 17.05%. The limits of detection of the method were 13.43-80.2 ng/L. The limits of quantification were 44.77-267.37 ng/L. This method was successfully applied to the determination of metabolism of phthalates in human urine with efficiency, increased accuracy and high sensitivity.

Key words: high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), isotope internal standard method, phthalate metabolites, solid-phase extraction (SPE), urine