Quantification of Urinary Mono-hydroxylated Metabolites of Polycyclic Aromatic Hydrocarbons by on-line Solid Phase Extraction-High Performance Liquid Chromatography-Tandem Mass Spectrometry

Human exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). Gas chromatography (GC) has been widely used to separate OH-PAHs before quantification by mass spectrometry in biomonitoring studies. However, because GC requires derivatization, it can be time consuming. We developed an on-line solid phase extraction coupled to isotope dilution-high performance liquid chromatography-tandem mass spectrometry (on-line-SPE-HPLC-MS/MS) method for the quantification in urine of 1-OH-naphthalene, 2-OH-naphthalene, 2-OH-fluorene, 3-OH-fluorene, 1-OH-phenanthrene, the sum of 2-OH and 3-OH-phenanthrene, 4-OH-phenanthrene, and 1-OH-pyrene. The method, which employed a 96-well plate platform and on-line SPE, showed good sensitivity (i.e., limits of detection ranged from 0.007 to 0.09 ng/mL) and used only 100 μL of urine. Accuracy, calculated from the recovery percentage at three spiking levels, varied from 94 to 113 %, depending on the analyte. The inter- and intra-day precision, calculated from 20 repeated measurements of two quality control materials, varied from 5.2 to 16.7 %. Adequate method performance was also confirmed by acceptable recovery (83-102 %) of two NIST standard reference materials (3672 and 3673). This high-throughput on-line-SPE-HPLC-MS/MS method can be applied in large-scale epidemiological studies. Graphical abstract Example LC-MS chromatogram of urinary mono-hydroxylated PAH metabolites.