Objective To develop a method for simultaneous determination of 11 hydroxy-polycyclic aromatic hydrocarbons(OH-PAHs) in urine by ultra-high performance liquid chromatography tandem with mass spectrometry(UPLC-MS/MS).

Methods The urine sample was hydrolyzed by β-glucuronidase/arylsulfatase in a water bath at 37℃ under the condition of pH 5.5 for 16 h away from light overnight, then extracted by 3.0 mL n-hexane. The upper organic phase was separated from urine sample by vortex and centrifugation. The extraction procedure was repeated twice and the two extracts were combined, and evaporated with nitrogen gas to almost dryness. The residues were re-dissolved in 20% acetonitrile solution, followed by gradient elution and separation by a CORTECS C18 column with 10% isopropanol methanol solution and water as mobile phases. The internal standard method was performed to measure the concentrations of 11 OH-PAHs by UPLC-MS/MS under ESI-mode.

Results The method showed good linearity for the 11 OH-PAHs (r>0.997), with detection limits of 0.01-0.10 ng/mL. The inter-day recoveries were 79.8%-97.3%, with relative standard deviations of 1.9%-4.7% (n=3), and the intra-day recoveries were 78.6%-92.3%, with relative standard deviations of 3.7%-7.1% (n=3).

Conclusion The proposed method is sensitive and accurate, and is suitable for the monitoring of multiple OH-PAHs in human urine samples.