Determination of three hydroxyl polycyclic aromatic hydrocarbons in urine using magnetic solid-phase extraction with magnetic carbon nitride composites coupled with high performance liquid chromatography

: A method based on the magnetic solid-phase extraction using magnetic carbon nitride composites coupled with high performance liquid chromatography-fluorescence detector (HPLC-FLD) was developed for the simultaneous determination of three hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs) in urine. The synthesized sorbent was characterized by scanning electron microscope, X-ray diffractometer, vibrating sample magnetometer and surface area analyzer. The extraction parameters such as amount of sorbent, extraction time, eluting solvent and volume (single eluting volume×eluting times) were investigated in detail. Under the optimized conditions, the method showed a linear range of 0.25-250 μg/L (correlation coefficient=0.999). The limit of detection was 0.08 μg/L and the limit of quantification was 0.25 μg/L for each analyte. The proposed method gave a recovery of 90.1%-102%. The relative standard deviations for the intra-day and inter-day were 1.5%-7.7% and 2.2%-8.7%, respectively. The feasibility of the developed method was further demonstrated during the analysis of real samples. The results indicate that the magnetic carbon nitride composites can be used for the effective purification and enrichment of three OH-PAHs in urine. In addition, the method can be applied for analysis of urinary OH-PAHs in a simple, fast, and effective manner.