Determination of residual clenbuterol in pork meat and liver by HPLC with electrochemical detection.

Aim: To detect the residual clenbuterol in pork meat and liver using HPLC with Coulometric electrode array system.
Methods: Homogenized meat or liver sample was treated with 1 mol x L(-1) hydrochloric acid and centrifuged, the fat existing in meat or liver tissue was removed by diethyl ether. The pH of the remaining aqueous layer was adjusted to 10.8 +/- 0.2 or 11.6 +/- 0.2 for meat or liver and liquid-liquid extraction with diethyl ether was followed. The ether extract was evaporated to dryness, the residue was dissolved in the mobile phase. The mobile phase A consisted of 50 mmol x L(-1) phosphoric acid-30 mmol x L(-1) triethylamine and was adjusted to pH 4.0 with 2 mol x L(-1) sodium hydroxide solution. The mobile phase B consisted of methanol-acetonitrile (30:45). A mixture of mobile phase A and B (80:20) was used in the method. A four electrode array module was selected for quantitation, the electrode potentials were set at 450, 600, 650 and 680 mV respectively.
Results: The two calibration curves for meat and liver showed good linearity between 1.88 - 60.16 ng x g(-1), the detection limit of clenbuterol was 1.2 ng x g(-1).
Conclusion: This method using HPLC-electrochemical detection is reproducible, and the sensitivity is good enough for the determination of clenbuterol in meat and liver.