Cyclic voltammetry behavior of tamoxifen in different electrolytes, electrochemical characterization, and its measurement by differential pulse anodic voltammetry

Abstract

Cyclic voltammetry (CV) was performed on tamoxifen (tam) using different electrodes and in various acidic electrolytes containing 10% v v$^{-1}$ methanol (MeOH). Tam oxidation was found to be most favorable using 0.1 mol L$^{-1}$ H$_{2}$SO$_{4}$. To investigate the mechanism, we performed chronoamperometry, CV at different scan rates, differential pulse anodic voltammetry (DPAV), and electrochemical impedance spectroscopy on tam-covered glassy carbon electrodes (GCEs). The electrode area, diffusion coefficient, and surface concentration ($\Gamma )$ of tam were calculated to be 0.062 cm$^{2}$, 3.65 $\times $ 10$^{-6}$ cm$^{2}$ s$^{-1}$, and 3.2 $\times $ 10$^{-10}$ mol cm$^{-2}$ respectively. Then the effects of different parameters on the DPAV were optimized. The best conditions were 2.5% v v$^{-1}$ cMeOH, 0.1 mol L$^{-1}$ H$_{2}$SO$_{4}$, deposition potential 0.4 V, deposition time 30 s, and GCE rotating rate 400 rpm. Therefore, the calibration curve was plotted in the range of 0.5 to 5 $\mu $g mL$^{-1}$. The limits of detection and quantitation (LOD and LOQ) were found to be 0.008 and 0.025 $\mu $g mL$^{-1}$, respectively. The relative bias and standard deviation of 2 $\mu $g mL$^{-1}$ tam were estimated to be 5% (n = 5) and 2.3%, respectively. Finally, the proposed method was successfully employed for the determination of tam in real samples.