Rapid magnetic solid-phase extraction based on magnetic graphitized carbon black for the determination of 1-naphthol and 2-naphthol in urine

Abstract In the present study, 1-naphthol (1-NAP) and 2-naphthol (2-NAP) were extracted from urine by magnetic solid phase extraction (MSPE) based on magnetic graphitized carbon black (M-Fe 3 O 4 @C) and analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). M-Fe 3 O 4 @C was fabricated by simple physical blending method, briefly, the graphitized carbon black (GCB) and Fe 3 O 4 nanoparticles were directly mixed and ground in a mortar. In this process, Fe 3 O 4 were physically wrapped and adhered to GCB forming the M-Fe 3 O 4 @C which can be easily collected and isolated from sample solution by a magnet. The prepared M-Fe 3 O 4 @C was used as MSPE adsorbent for isolation of 1-NAP and 2-NAP from urine via hydrophobic and π − π interaction. Several parameters which would affect the extraction efficiency were investigated. Under the optimal condition, the whole pretreatment process can be accomplished within 15 min. The linearity range of the proposed method was 10–5000 μg/L with satisfactory correlation coefficients (R 2 ) of 0.9982–0.9983. The limits of detection (LOD) were 0.9 μg/L for 1-NAP and 1.1 μg/L for 2-NAP. The recoveries in spiked urine were in the range of 78.2–103%, with the RSDs n  = 6) and 9.9% (inter-day, n  = 3). Finally, the established method was successfully applied to detect naphthols in college student volunteers and the workers of petrochemical company.