Abstract: A novel casein immunosensor for detectingαs-casein was developed through the modification of chitosan and nano-gold on the glassy carbon electrode. The modification procedure was electrochemically monitored by cyclic voltammetry to explore the characteristics of the electrode surface and the performance of the immunosensor. The developed immunosensor was used to detectαs-casein in phosphate buffer. An excellent linear range between response current andαs-casein concentration was observed in the concentration range of 1－10000 ng/mL. Therefore, this developed immunosensor is characteristics of simple preparation, low cost, convenient operation, and can be applied to the safety detection of milk.

Key words: immunosensor, chitosan, nano-gold, casein, chronoamperometry, biosensor, glassy carbon electrode, cyclic voltammetry