Separation and determination of abused drugs clenbuterol and salbutamol from complex extractants in swine feed by capillary zone electrophoresis with simple pretreatment

A simple but efficient capillary zone electrophoresis (CZE) method was developed for the fast separation and determination of two misused beta 2-agonists clenbuterol (CLB) and salbutamol (SAL) from complex background extractants existing in swine feed samples. The proper experimental conditions were achieved as 20.0 mmol/l pH 10.5 Na-2 HPO4-NaOH buffer, 20 kV applied voltage, fused-silica capillary of 60.5 cm x 75 mu m i.d. (50 cm to detector). Under the proper conditions, the two abused drugs can be online isolated from the complex extractants and the separation between CLB and SAL is good, all of the target analytes can be detected within 4.5 min. The linear response of CLB and SAL concentration ranges from 2.0 to 100.0 mu g/ml with high correlation coefficient (R-2 = 0.9990) and (R-2 = 0.9986), respectively. Limit of detection (LOD) and limit of quantification (LOQ) was calculated to be 0.95 and 3.17 mu g/ml for CLB, 1.07 and 3.57 mu g/ml for SAL. The precision values (expressed as R.S.D.) of intra- and inter-day were 1.24-2.36% and 0.90-3.85% for CLB, 0.47-1.64% and 0.91-3.46% for SAL. Recoveries spiked at levels 5.0, 25.0, 80.0 mu g/ml ranged between 93.30% and 104.33% with R.S.D. less than 5%. Finally, the developed method has been applied to the analysis of real swine feed samples and has achieved satisfactory results. (C) 2008 Elsevier B.V. All rights reserved.