Simultaneous determination of 2-naphthol and 1-hydroxy pyrene in urine by gas chromatography-mass spectrometry

A gas chromatography-mass spectrometric (GC-MS) method was developed for the determination of 2-naphthol (2-NAP) and 1-hydroxypyrene (1-HOP) in human urine. Extraction from urine after the enzyme hydrolysis with β-glucuronidase/arylsulfatase was achieved with a liquid extraction using 5 mL of pentane. After addition of 50 μL of N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBDMSTFA) to prevent the loss of 2-NAP during drying, the extract was completely dried and derivatized with MTBDMSTFA for 30 min at 60 °C. The accuracies were in the range of 96-109% at a concentration of 0.5, 10 and 25 μg/L and their precisions were less than 15%. Method detection limits of 2-NAP and 1-HOP were 0.07 and 0.01 μg/L, respectively. This method was used to analyze twenty urine samples, and they were found in the concentration range <0.07-13.7 μg/L (2-NAP) and <0.01-0.88 μg/L (1-HOP). The concentrations of 2-NAP and 1-HOP were well correlated to those of naphthalene and pyrene in blood, respectively.