Optimization of Square Wave Voltammetry Parameters Using Response Surface Methodology for Sensitive Determination of 4-Aminophenol on a Modified Electro-chemical Sensor Surface
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Abstract
To enhance the measurement sensitivity in the voltammetric determination of 4-AP, the surface of a glassy carbon electrode (GC) was modified with 1H-1,2,4-triazole-1-carboximidamide (1T1C) in a 0.1 M H2SO4 solution. The resulting 1T1C-coated GC surface (1T1C/GC) was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). For the determination of 4-AP, an acetate buffer solution (ABS) at pH 4.0 was identified as the most suitable supporting electrolyte. Scan rate studies performed in this medium enabled the analysis of the electrochemical behavior and oxidation mechanism of 4-AP at the 1T1C-modified GC surface. The electrochemical behavior of 4-AP was investigated using CV, differential pulse voltammetry (DPV), and square wave voltammetry (SWV), with the highest anodic peak current obtained by the SWV technique. Within the SWV method, the frequency, pulse amplitude, and potential step parameters were optimized using Response Surface Methodology (RSM) in combination with a Box–Behnken design (BBD). Under the optimized conditions, the oxidation peak currents of 4-AP were measured at both the bare GC and the 1T1C-coated GC electrodes. The signal obtained with the 1T1C/GC electrode was approximately two fold higher than that of the bare GC electrode, clearly demonstrating that the applied modification enhanced the sensitivity of the electrode surface toward 4-AP determination.
Keywords
Abstract
To enhance the measurement sensitivity in the voltammetric determination of 4-AP, the surface of a glassy carbon electrode (GC) was modified with 1H-1,2,4-triazole-1-carboximidamide (1T1C) in a 0.1 M H2SO4 solution. The resulting 1T1C-coated GC surface (1T1C/GC) was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). For the determination of 4-AP, an acetate buffer solution (ABS) at pH 4.0 was identified as the most suitable supporting electrolyte. Scan rate studies performed in this medium enabled the analysis of the electrochemical behavior and oxidation mechanism of 4-AP at the 1T1C-modified GC surface. The electrochemical behavior of 4-AP was investigated using CV, differential pulse voltammetry (DPV), and square wave voltammetry (SWV), with the highest anodic peak current obtained by the SWV technique. Within the SWV method, the frequency, pulse amplitude, and potential step parameters were optimized using Response Surface Methodology (RSM) in combination with a Box–Behnken design (BBD). Under the optimized conditions, the oxidation peak currents of 4-AP were measured at both the bare GC and the 1T1C-coated GC electrodes. The signal obtained with the 1T1C/GC electrode was approximately two fold higher than that of the bare GC electrode, clearly demonstrating that the applied modification enhanced the sensitivity of the electrode surface toward 4-AP determination.