Abstract
The construction and electrochemical response characteristics of Poly (vinyl chloride) membrane sensors for bambuterol HCl (Bb) are described. The sensing membranes incorporate ion association complexes of bambuterol cation and phosphomolybdic acid (PMA) (sensor 1) and phosphotungstic acid (PTA) (sensor 2) as electroactive materials. The sensors display a fast, stable and near-Nernstian response over a relative wide bambuterol concentration range (1 × 10−2 to 7×10−6, and 1 × 10−2 to 6.0×10−6M), with detection limits of 5×10-6, and 3×10-6 for sensor 1, and 2, respectively over a pH range of 3.0 - 8.0. The sensors show good discrimination of bambuterol from several inorganic and organic compounds. The direct determinations of 200 μg/ml of Bb show an average recovery 98.5 and 99.0% and a mean relative standard deviation of 1.5 a n d 1.7 % at 200.0 μg/ml for sensor 1 and 2 respectively. The proposed sensors have been applied for direct determination of Bb in some pharmaceutical preparations. The results obtained by determination of Bb in tablets using the proposed sensors are comparable favorably with those obtained using the British Pharmacopeia method. The sensors have been used as indicator electrodes for potentiometric titration of bambuterol.