Determination of β2-agonists by ion chromatography with direct conductivity detection

A simple method for the simultaneous detection of four β2-agonists (salbutamol, fenoterol, clorprenaline, and clenbuterol) using ion chromatography (IC) with direct conductivity detection (CD) based on their ionization in acidic medium without chemical suppression is presented. The mixture of 1.8 mM HNO3 and 2% (v/v) acetonitrile was used as eluent. The method could be applied to the determination of the β2-agonists in pharmaceutical preparations. The recovery of salbutamol and clenbuterol in tablets was more than 97% (n = 3) and the relative standard deviation (n = 11) less than 2.8%. With the proposed method, salbutamol could also be successfully detected in human plasma. In a single chromatographic run, the four β2-agonists can be separated and determined in less than 8 min. The linear ranges were of 7.0-1.4 × 103 ng/ml for salbutamol, 34-7.8 × 103 ng/ml for fenoterol, 8.0-1.6 × 103 ng/ml for clorprenaline, and 25-7.5 × 103 ng/ml for clenbuterol. The detection limits were 2.0 ng/ml for salbutamol, 10 ng/ml for fenoterol, 3.0 ng/ml for clorprenaline, and 10 ng/ml for clenbuterol.