Study on simultaneous determination of three nitroimidazole residues in honey by high performance liquid chromatography-resonance Rayleigh scattering spectra

A novel and high sensitivity method that high performance liquid chromatography combined with resonance Rayleigh scattering is established for the determination of nitroimidazole residues in honey, including Metronidazole (MNZ), Ornidazole (ONZ) and Tinidazole imidazole (TNZ). In pH 3.8 BR buffer solution, the three nitroimidazole drugs separated by HPLC, and then reacted with a post-column derivatization Phloxine B (PB) in the reaction tube to form 1:1 ion-association complex, which Leads to significant enhancement of the RRS signal. This paper optimized the experimental conditions of post-column derivation and discussed the mechanism of reaction for the enhancement of RRS signal. Under the optimal experimental conditions, the RRS signals of the three nitroimidazole drugs were enhanced with the increase of its concentration in the respective linear range. The detection limit (S/N) of MNZ, ONZ and TNZ was: 0.013 μg·mL−1, 0.049 μg·mL−1 and 0.27 μg·mL−1, respectively. The recovery rate was 97.4%-102.2%, and the relative standard deviation (RSD) does not exceed 5.3%, the reliability of this technique is verified, and the result of this method is satisfyingly.