Abstract
The construction and electrochemical response characteristics of Poly (vinyl chloride) (PVC) membrane sensors for arecoline HBr (AR) are described. The sensing membranes incorporate ion association complexes of (AR) cation and sodium tetraphenyl borate (NaTPB) (sensor 1) or phosphomolybdic acid (PMA) (sensor 2) or phosphotungstic acid (PTA) (sensor 3) as electroactive materials. The sensors display a fast, stable and near-Nernstian response over a relative wide AR concentration range (1x10-2-4x10-5M) and (1x10-2 to 5x10-6M), with cationic slopes of 52.5, 50.5 and 51.5mV per concentration decade for sensor 1, 2, and 3, respectively over a pH range of 3.0-6.0. The sensors show good discrimination of AR from several inorganic and organic compounds. The direct determination of 1.5-2360.0g/ml of AR show an average recovery of 99.0, 98.5 and 99.5% and a mean relative standard deviation of 1.7, 1.6 and 1.5% at 200.0g/ml for sensor 1, 2 and 3 respectively. The proposed sensors have been applied for direct determination of AR in human saliva. The results obtained for determination of AR in saliva using the proposed method comparable favorably with those obtained using HPLC method.