Electromembrane extraction of clenbuterol from swine urine for monitoring illegal use in livestock.

The illegal use of clenbuterol seriously endangers food safety and human health. Accurate monitoring of the illegal use of clenbuterol in livestock can efficiently prevent the clenbuterol residue pork products from entering the consumer market. Thus, in this study, a simple, rapid, and sensitive method for the determination of clenbuterol in swine urine was developed using electromembrane extraction combined with liquid chromatography-tandem mass spectrometry. It should be noted that the electromembrane extraction method presented many advantages of simple operation, fast mass transfer rate, good sample clean-up capability, and less organic solvent consumption. The effect of important factors on the extraction efficiency of clenbuterol was investigated. Under the optimal conditions, good linearity was achieved for clenbuterol over the range of 1-1000 ng/ml (linear correlation [R ] = 0.9996). The recoveries of clenbuterol in swine urine at three spiked levels ranged from 83.7% to 110.0% with relative standard deviation values lower than 9.7% (n = 4). The limits of detection and quantification for clenbuterol were 0.07 and 0.25 ng/ml, respectively. These results suggested that the proposed method has great potential for the extraction and determination of trace analyte in a complex sample matrix for monitoring illegal use in livestock.