Abstract: The residues of veterinary drugs in food of animal origin have potential hazards to people’s health. In this paper, a homemade surface plasmon resonance (SPR)-based biosensor was used to develop a sensitive and fast immunoassay to determine sulfamethazine(SMT). The conditions of the immobilization of the antigen on the chip were studied and the concentration of antibody was optimized. The standard curve was constructed. The LOD (limit of detection) was 0.7 ng/ml (n=5) with the detection scope 0.7～10 ng/ml.The specificity and the stability of the antibody were also studied. The SPR-2004 biosensor was home-made with one channel and the sensor chip had two surfaces including a reference surface that could cancel the change of refractive index and non-specific adsorption to improve the quality of the data and to also decrease the detection time.

Key words: surface plasmon resonance, biosensor, reference surface, sulfamethazine