Simultaneous determination of paracetamol and 4-aminophenol based on poly(chromium Schiff base complex) modified electrode at nanomolar levels

Highly selective and sensitive electrochemical method was developed for the simultaneous determination of paracetamol (PR) and 4-aminophenol (4-AP) present in the pharmaceutical samples. Poly(chromium Schiff base complex) was fabricated onto the glassy carbon electrode by cyclic voltammetry technique. The modified glassy carbon electrode (GCE) has exhibited better electrochemical response towards the simultaneous determination of paracetamol and 4-aminophenol than the GCE. Additionally, the chromium Schiff complex modified GCE exhibits quasireversible process for PR and reversible process for 4-AP, when compared to that of GCE, this response may be attributed to the presence of Cr(III) in the modified layer. The effect of pH and scan rate was evaluated for the fabricated sensor in order to know the optimum conditions at which better response can be achieved. Moreover the kinetic parameter of the fabricated sensor was calculated separately for both the analytes. From differential pulse voltammetric (DPV) technique, the peak separation between the PR and 4-AP was found to be 300 mV and the electrochemical responses of the both analytes fall in the linear range from 8 nM to 125 nM and 8 nM to 133 nM, with the detection limits of 6.8 nM and 5.6 nM for PR and 4-AP respectively. From these studies, the proposed method based on electropolymerized chromium Schiff base complex was simple, rapid, cost effective and convenient for the simultaneous determination of PR and 4-AP at nanomolar levels in pharmaceutical samples. (C) 2016 Elsevier Ltd. All rights reserved.