Determination of Hydroxy Polycyclic Aromatic Hydrocarbon Metabolites in Urine by Liquid liquid Extraction-High Resolution Gas Chromatography-High Resolution Double Focusing Magnetic Mass Spectrometry

A sensitive and accurate method was developed to quantify eight polycyclic aromatic hydrocarbon (PAH) metabolites in human urine by liquid-liquid extraction-high resolution gas chromatography-high resolution dual-focus magnetic mass spectrometry (LLC-HRGC-HRMS). About 2 mL urine was mixed with a deuterium- or C-13-labeled isotopic internal standard, and the conjugated targets were enzymatically digested in the presence of ascorbic acid. The free compounds were extracted with toluene-pentane (1 :4, v/v) and condensed to near dryness. Then, the target compounds were redissolved in toluene. After derivatization, they were separated and quantified by HRGC-HRMS. The linear ranges of the 1-hydroxynaphthalene, 1-hydroxyphenanthrene, and 2-hydroxyphenanthrene were 0.14-41.6 mu g/L, 0.05-8.33 mu g/L, and 0.04-8.33 mu g/L, respectively, and those for the other five PAH metabolites were 0.02-8.33 mu g/L. The correlation coefficients were greater than 0.99. The limits of detection were in the range of 0.006-0.042 mu g/L, and the recoveries were 81.4%-127.0%. The intra-day and inter-day relative standard deviations (RSDs) were less than 6.9% and 10.9%, respectively. This method was utilized for the determination of 330 human urine samples. The results showed that 3-hydroxychrysene and 6-hydroxychrysene were not detected, and the detection rate of the other six PAH metabolites was 100%. This method is sensitive, accurate and stable, and it is suitable for the determination of the eight PAH metabolites in human urine.