Sensitivity enhancement of ionic liquid modified carbon paste electrodes for electro analysis of metal ions

Abstract

Modified carbon paste electrodes (CPEs) are widely used in the electrochemical analysis of metal ions for their simple design and easy preparation methods.In this study, we have demonstrated the modification of CPE with a room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6]. This ionic liquid was used as a binder to construct modified CPEs. This thesis aimed to develop an electrochemical sensor forsensitive detection of lead ion. Differentcombinations of graphite, paraffin oil and IL mixtures were tested for the finestsensitive detection of metal ion. The prepared materials were characterized using different physical and chemical methods. Compression test were done to observe the mechanical behavior of the modified electrode. Material morphology were characterized by scanning electron microscopy (SEM). The electrochemical response of the modified electrode towards the analytes was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and differential pulse anodic stripping voltammetry (DPASV). It was observed that the electro active surface area of the electrode was found to be 0.06 cm2.The DPASV signals were analyzed and relevant parameters were optimized for lead ions. Overall, the response of modified electrode and sensitivity were significantly improved by the addition of an optimum concentration of [bmim][PF6], in comparison with the conventional CPEs.The results indicated that ILCPE_15 materials showed the best electrochemical response to the DPASV with a limit of detection to 12.60 ppb.