Determination of nine phthalate ester metabolites in human urine using ultra high performance liquid chromatography-tandem triple quadrupole mass spectrometry

Abstract

A method was developed to determine trace concentrations of phthalate ester (PAE) metabolites in human urine by using ultra high performance liquid chromatography-triple quadrupole mass spectrometry. Aliquots (2 mL) of human urine samples were purified using strong anion-exchange solid-phase extraction after enzymatic deconjugation by glucuronidase for 2 h. The separation was performed on a Waters ACQUITY UPLC BEH Phenyl column (100 mm×2.1 mm, 1.7 μ m) with gradient elution by 0.1% (v/v) acetic acid in acetonitrile and 0.1% (v/v) acetic acid aqueous solution. The concentrations of nine PAE metabolites were determined under a multiple reaction monitoring mode by negative electrospray ionization. Eight of the determined metabolites showed good linearities in the range of 0.39-200 μ g/L, and the ninth metabolite showed linearity in the range of 1.17-600 μ g/L with correlation coefficients > 0.995. The limits of detection ranged from 0.06 to 0.85 μ g/L, and the limits of quantification ranged from 0.20 to 2.80 μ g/L. The recovery rates at all three spiked levels ranged from 84.1% to 122% with relative standard deviations between 4.5% and 14.3%. The intra-and inter-day precisions were not more than 10.1% and 9.3%, respectively. The matrix effect and stability were found to be favorable for analysis. This method was utilized for the determination of 50 human urine samples. The detection rates of monocyclohexyl phthalate (MCHP) and monobenzyl phthalate (MBZP) were 0 and 44.0%, and the detection rates of the other seven PAE metabolites was 100%. This method has the advantage of convenient operation and good accuracy and stability, and is suitable for the quantitative determination of the nine PAE metabolites in human urine.