Vortex-Assisted Surfactant-Enhanced Emulsification Microextraction Combined with High Performance Liquid Chromatography-Fluorescence Detector for Determination of Nitrite in Urine

摘要

A vortex-assisted surfactant-enhanced emulsification microextraction (VASEME) combined with high performance liquid chromatography-fluorecence detector (HPLC-FLD) procedure was developed for the determination of trace nitrite in human urine. The method is based on the selective reaction of nitrite with o-phenylenediamine in acid media to form benzotriazole, which exhibited strong fluorescence at 568 nm with excitation at 420 nm in alkaline medium. The fluorescence of system was enhanced by hydroxypropyl-p-cyclodextrin (HP-β-CD) ihrough complexation. The nonionic surfactant Triton X-l 14 was adopted as emulsifier and n-octanol as the extraction solvent and nix was applied to assist emulsification in vortex-assisted surfactant-enhanced emulsification microextraction. Under the optimal conditions: the linearity was observed in the range of 4 to 80 ng/mL and the correlation coefficient ( r) was 0.996. The relative standard deviations were below 3.7 % (n = 5). The limit of detection (LOD) based on a signal-to-noise ratio (SIN) of 3 was 0.08 ng/mL and a signal to-noise ratio (S/N) of 10 the quantification limits (LOQ) was 0.314 ng/mL. Good recoveries (> 85 %) were obtained when the proposed method was applied to determine nitrite in human urine samples.