Combined immunoextraction approach coupled to a chemiluminescence enzyme immunoassay for the determination of trace levels of salbutamol and clenbuterol in tissue samples.

A monoclonal immunoglobulin G1 (IgG1) antisalbutamol, which exhibits a 75% cross-reactivity with clenbuterol, has been used in the setup of an immunoaffinity chromatography method and a chemiluminescence enzyme immunoassay for the extraction and the quantification of salbutamol and clenbuterol in tissue samples. After analytical validation, the proposed methodology was applied to liver, kidney and muscle samples obtained from calves and pigs treated with these beta 2-agonists (100 micrograms per kg of body weight) for 10 d. This methodology allowed the quantification of both drugs until 6 d after the final dose. At this time, however, salbutamol and clenbuterol were concentrated in the liver. Our results indicate that the liver is the preferred tissue to sample for the detection of illegal use of beta 2-agonists as growth promoters, in the absence of urine samples.