GC-APLI-MS as a powerful tool for the analysis of BaP-tetraol in human urine

Abstract For the first time gas chromatography (GC) coupled to atmospheric pressure laser ionization-mass spectrometry (APLI-MS) has been applied to the analysis of trans - anti -benzo[ a ]pyrene-tetraol (BaP-tetraol) formed from anti -benzo[ a ]pyrene diolepoxide (BPDE), the ultimate carcinogen of benzo[ a ]pyrene. This tetraol is considered to be an ideal urinary biomarker for polycyclic aromatic hydrocarbon (PAH) exposure as it reflects internal body burden and potentially adverse health effects. Optimization of the derivatization and the instrumental set-up led to an instrumental LOD of 0.5 fg, an improvement of the lowest instrumental LOD reported in literature of 6.4 fg by a factor of 10. The optimized procedure includes derivatization of hydroxyl groups using methyl iodide and cool on-column injection to prevent degradation of the analyte. First measurements of urine samples demonstrate that the method is capable of detecting BaP-tetraol in human urine collected from both smokers and non-smokers. Although results of analysis indicate a certain underestimation compared with literature data, this method can be expected to serve as an excellent method for the analysis of the biomarker BaP-tetraol in the future if an adequate internal standard such as 13 C-labeled BaP-tetraol is applied.