Simultaneous determination of ranitidine and metronidazole in pharmaceutical formulations at poly(chromotrope 2B) modified activated glassy carbon electrodes

A simple and sensitive electrochemical method for the simultaneous and quantitative detection of ranitidine (RT) and metronidazole (MT) was developed, based on a poly(chromotrope 2B) modified activated glassy carbon electrode (PCHAGCE). The PCHAGCE showed excellent electrocatalytic activity toward the reduction of both RT and MT in 0.1 mol/L phosphate buffer solution (pH 6.0). The peak-to-peak separations for the simultaneous detection of RT and MT between the two reduction waves in cyclic voltammetry were increased significantly from ∼0.1 V at activated GCE, to ∼0.55 V at PCHAGCE. By differential pulse voltammetry techniques, the reduction peak currents of RT and MT were both linear over the range of 1.0 × 10−5–4.0 × 10−4 mol/L. The detection limits (S/N = 3) were 5.4 × 10−7 mol/L and 3.3 × 10−7 mol/L for RT and MT, respectively. The modified electrode was successfully applied to the determination of RT and MT in pharmaceutical preparations and human serum as real samples with stable and reliable recovery data.