Application of (2,2′:6′,2″-terpyridyl) copper(II) chloride complex in sensor construction for benzoyl peroxide determination in pharmaceutical samples Original Research Article

This work describes an alternative method for benzoyl peroxide (BP) determination in pharmaceutical samples, using an amperometric sensor based on a carbon paste modified with (2,2′:6′,2″-terpyridyl) copper(II) chloride complex [Cu(terpy)Cl]Cl·2H2O. The sensor presented the best response in 0.10 mol l−1 phosphate buffer solution (pH 7.0) applying a potential of −50 mV versus SCE. In the optimized conditions the sensor showed a linear response range for BP from 0.9 to 5.0 μg ml−1. The response time for this sensor was 0.5 s. The paste presented a stability of at least 6 months at room temperature. The precision of the measurements was 4.5%, expressed in term of relative standard deviation (R.S.D.) for n=5. A detailed study was carried out, in order to investigate the sensor response for some compounds contained in pharmaceutical formulations, such as carboxypolymethylene (carbopol® 940), triethanolamine, propyleneglycol, hydroxyethylcellulose (natrosol®), and no interference was observed with these compounds. The applicability of the sensor for BP determination was evaluated in pharmaceutical preparations, obtaining recovery averages of 98±1%.