Voltammetric study of 2-guanidinobenzimidazole: Electrode mechanism and determination at mercury electrode

Abstract

Although 2-guanidinobenzimidazole (GBI; CAS: 5418-95-1) is a compound of biological interest, generally there is a lack of electrochemical studies and the methods of its determination. The GBI behavior at a mercury electrode was analyzed under conditions of linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), square-wave voltammetry (SWV) and square-wave stripping voltammetry (SWSV). Although GBI is electrochemically inactive at mercury electrode it adsorbs at the mercury surface and catalyzes effectively the hydrogen evolution reaction. Theoretical analysis of two possible pathways, according to which the GBI electrode mechanism can be explained, is performed. Simple analysis of peak current and potential with respect to available time window, i.e. change of frequency can be helpful in discerning the character of the recorded SW current. The established electrode mechanism is assumed to involve a preceding chemical reaction in which the adsorbed catalyst (GBI ads ) is protonated and the protonated form of the catalyst (GBIH + (ads) ) is irreversibly reduced at potential about -1.18 V vs Ag|AgCl (citrate buffer pH 2.5). New methods of voltammetric determination of 2-guanidinobenzimidazole were developed. The detection and quantifications limits were found to be 1 × 10 -7 , 1 × 10 -6 mol l -1 (SWV); 8 × 10 -8 , 9 × 10 -7 mol l -1 (SWSV); 4 × 10 -7 , 2 × 10 -6 mol l -1 (DPV) and 6 × 10 -7 , 3 × 10 -6 mol l -1 (LSV), respectively.

Voltammetric behaviour and quantitative determination of pesticide iminoctadine

“…4 Such a procedure can be used in experiments with working electrodes containing mercury when adsorption takes place and the type of electrode mechanism can be concluded from the inuence of frequency on the recorded peak current. The investigation based on the frequency requires the examination of several dependences: 3,4,[38][39][40] As demonstrated in ref. 3, the overall catalytic effect depends on the k cat ¼ k p /f (dimensionless catalytic parameter), where k p ¼ k 0 p  C H + and k 0 p is the protonation rate constant.…”

Electroreduction of Bi(III) ions in the aspect of expanding the “cap-pair” effect: the role of the nanosized active complexes

“…It should be noted that in the extensive spectrum of analytical techniques, few methods satisfy all these criteria. Electrochemical measurement techniques such as square Wave Voltamperometry (SWV), Pulse Differential Voltamperometry (DPV), Square Wave Stripping Voltamperometry (SWAdSV) or Cyclic Voltamperometry (CV) are commonly used to determine depolarisers and biologically active compounds as well as to study electrode mechanisms (Galus 1977(Galus , 1979Skrzypek et al 2011Skrzypek et al , 2012Mirceski et al 2005). At present, one of the fastest developing techniques is electrochemical impedance spectroscopy (EIS), which allows for determining the mechanisms of processes taking place at the electrode/solution interface or to investigate the applicability of new electrode materials (Lasia 1999).…”

Electroreduction of Bi(III) Ions in the Aspect of Expanding the ”Cap – Pair” Effect

“…It should be noted that in the extensive spectrum of analytical techniques, few methods satisfy all these criteria. Electrochemical measurement techniques such as square Wave Voltamperometry (SWV), Pulse Differential Voltamperometry (DPV), Square Wave Stripping Voltamperometry (SWAdSV) or Cyclic Voltamperometry (CV) are commonly used to determine depolarisers and biologically active compounds as well as to study electrode mechanisms [1][2][3][4][5]. At present, one of the fastest developing techniques is electrochemical impedance spectroscopy (EIS), which allows for determining the mechanisms of processes taking place at the electrode/solution interface or to investigate the applicability of new electrode materials [6].…”