Adsorptive stripping voltammetric determination of antihypertensive agent:diltiazem

Adsorptive stripping voltammetry was used to determine the antihypertensive agent diltiazem in phosphate buffer (pH 7.0). The adsorptive cathodic peak was observed at - 1.72 V vs. Ag/AgCl. The peak response was characterized with respect to pH, preconcentration time, possible interferences, accumula tion potential and supporting electrolytes. The obtained results were analy zed and the statistical parameters were calculated. The proposed method was applied to determine the mentioned drug in pharmaceutical formulation (cap sule) and urine. The detection limit is 1 x 10(-8) M (4.5 ng ml(-1)) using 180 s preconcentration time, whereas the lower limit of detection is 6 x 10 (-9) M (2.7 ng ml(-1)). (C) 2001 Elsevier Science B.V. All rights reserved.