Determination of Sulfonamide Residues in Milk by HighPerformance Liquid Chromatography-Chemiluminescence Method / 分析化学

ABSTRACT

Sulfonamides (SAs), such as sulfaguanidine (SGD), sulfadiazine (SDZ), sulfathiazole (STZ) and sulfamethazine (SMZ), can drastically inhibit the chemiluminescence (CL) intensities generated in both Ag-Luminol and Ni-Luminol systems.Based on these observations, a novel method of high performance liquid chromatography (HPLC) coupled with CL detection was established.Both the Ag-Luminol and Ni-Luminol CL systems were employed as detectors, and the performances of the two detecting systems were compared.After separated by HPLC, four SAs reacted with Ag-Luminol and Ni-Luminol CL system, respectively.Chromatographic conditions were as follows reversed-phase C18 column (250 mm × 4.6 mm,5 μm), gradient elution, and 0.1% (V/V) formic acid-methanol as mobile phase with flow rate of 1 mL/min.CL conditions were as follows [Ag]=1.4×10.-4 mol/L (in 0.12 mol/L NaOH);[Ni]=1.5×10.-5 mol/L (in 0.12 mol/L NaOH);[Luminol]=1.2×10.-7 mol/L;and flow rate=1.0 mL/min.Under the optimal conditions, the detection limits of Ag-Luminol CL system were 0.15, 0.96, 1.10, 1.50 μg/mL for SGD, SDZ, STZ, and SMZ, respectively, and the recovery were 81.0%-101.5%.Comparatively, the detection limits of Ni-Luminol CL system were 1.5, 17.2, 16.8 μg/mL for SGD, SDZ and STZ, and the recoveries was 83.9%-110.8%.The result showed that the Ag-Luminol CL system had a much better performance.The method was applied to the determination of the residues of the above four SAs in milk with satisfactory results.