Abstract: Ractopamine (RCT) is a phenethanolamine member of the family of β-adrenergic agonists(β-agonists). This class of compounds has become notable for their properties of enhancing the growth rates of farm animal species but is not licensed for use in China and other countries because of their serious side-effects. The RCT is coupled to BSA as an immunogen and to OVA as a coating antigen using the coupling agent, butane-1,4-diol diglyciydyl ether. The immunogen and coating antigen have been identified by the method of ultraviolet full wavelength scanner and SDS-PAGE. Polyclonal antibodies against RCT have been raised in three rabbits and purified by using a saturated ammonium sulfate method and by the way of protein A-Sepharose 4B. The sensitivity and cross-reactivity of polyclonal antibody have been demonstrated in ELISA test. The purified polyclonal anti- RCT antiserum shows a very high degree of sensitivity and specificity.

Key words: Ractopamine, immunogen, coating antigen, polyclonal antibody, ELISA