Differential-pulse adsorptive stripping voltammetry of chlorhexidine

Abstract

Chlorhexidine gluconate was shown to adsorb onto a hanging mercury drop electrode and to be amenable to quantification by adsorptive stripping voltammetry. A sensitivity of 1 × 10–7 mol dm–3 was easily achieved by simply immersing the electrode in a stirred solution (pH 9.7 ammonia-ammonium acetate buffer) of the drug for a fixed time (60 s), at a suitable potential (0.0 V versus Ag–AgCl), and then stripping cathodically in the differential-pulse mode. The stripping peak potential was –1.53 V. Cyclic voltammetry was used to test the interfacial and redox behaviour. Chlorhexidine gluconate was assayed in mouthrinse and contact lens solution dosage forms.