Abstract:

A method based on surface plasmon resonance technique was developed for rapid determination of sulfamethoxazole (SMX) in milk. SMX was covalently coupled to laboratory prepared CM5 chip to obtain SMX chip. The optimal antibody working concentration and chip regeneration conditions were investigated. Meanwhile, the stability of SMX chip was measured. A series of different concentrations of SMX was added to blank milk samples to construct a standard curve for SMX quantification according to the principle of competitive immune inhibition assay. Eighteen commercial milk samples were determined by the developed method. SMX chip displayed good stability, and the relative standard deviation (RSD) for 90 cycles was 1.23%. The limit of detection (LOD) of SMX was 3.2 ng/mL. SMX contents below the required threshold level were observed in 16 of 18 milk samples. Less than 15 min was consumed for the determination of SMX by the developed method. Thus, this method may offer a simple and efficient approach for SMX quantification.

Key words: surface plasmon resonance, chip, sulfamethoxazole