Magnetic Solid Phase Extraction Followed by High Performance Liquid Chromatography for Determination of Urinary 1-Hydroxypyrene
A method was established for the determination of urinary pyrene metabolite 1-hydroxypyrene (1-OHP) by the combination of magnetic solid-phase extraction (MSPE) and liquid chromatography-fluorescence detection. Good extraction efficiency was obtained by optimizing the extraction conditions. A 2-mL aliquot of urine sample was diluted to 4 mL with sodium acetate (pH 4.5, 0.1 M) followed by enzymatic hydrolysis. The hydrolyzed sample was further diluted to 10 mL with sodium acetate (pH 5.0, 0.1 M) and then extracted by MSPE using n-octadecylphosphonic acid modified magnetic mesoporous nanoparticles (OPA/MMNPs, 50 mg). The extraction time and desorption time were 1 min and 3 min, respectively, with methanol as the desorption solvent. Desorption solution was evaporated to dryness under a mild nitrogen stream at 35 °C, and then dissolved in mobile phase for HPLC separation. The linearity range of the detection method was 0.01-1.0 μg L−1 with a correlation coefficient of 0.9996. The limit of detection was 0.001 μg L−1. The intra- and inter-day precisions (RSDs) were less than 9.7% (n = 5) and 12.9% (n = 3), respectively, which indicated this method has a satisfying reproducibility. The proposed method was further successfully applied to the determination of 1-OHP concentration in urine samples by normalizing to urinary creatinine. Collectively, the rapid, convenient and cost-effective method developed in current study offers a potential application to evaluate the human body PAHs exposure by determination of urinary 1-OHP.