Abstract:

Salbutamol-ractopamine-bovine serum albumin conjugate (SAL-RAC-BSA) was prepared and served as
immunogen to obtain a broad-spectrum specific antibody (anti-SAL-RAC-BSA Abs) through immunization of rabbits.
Electrochemical immunosensor modified with reduced graphene oxide-chitosan composite and SAL was constructed and
its electrochemical behavior was studied by cyclic voltammetry and electrochemical impedance spectroscopy. Indirect
competitive electrochemical immunoassay was carried out for the simultaneous determination of three β2-agonis, including
clenbuterol (CL), salbutamol (SAL) and terbutaline (TB). The proposed method indicated a linearity in the range from 50 to
7 000 ng/mL, 1 to 1 500 ng/mL and 100 to 6 000 ng/mL for CL, SAL and TB, respectively, and the limits of detection were
0.2, 0.3 and 0.3 ng/mL, respectively. The recovery rates of clenbuterol in spiked pork, fat and liver samples ranged from
84.7% to 106%. In summary, a sensitive, rapid and simple electrochemical immunoassay was successfully developed for the
determination of three β2-agonists.

Key words: broad-spectrum specific antibodies, β2-agonists, multi-residue, electrochemical immunosensor