Poly (l-Proline) modified carbon paste electrode as the voltammetric sensor for the detection of Estriol and its simultaneous determination with Folic and Ascorbic acid

Abstract

Electrochemical sensor based on electro-polymerization of l-Proline at the carbon paste electrode (CPE) by cyclic voltammetric (CV) technique for the sensitive detection of Estriol (ET) was developed. The modification of CPE with poly (l-Proline) has enhanced the electrochemical oxidation of ET with increased current sensitivity in 0.1 M phosphate buffer solution (PBS) of pH 6.5 by CV and Differential Pulse Voltammetry (DPV). The surface morphology of both the bare carbon paste electrode (BCPE) and the modified carbon paste electrode (MCPE) was examined by utilizing Field emission scanning electron microscopy (FESEM). Various parameters such as the effect of peak potential (Epa), the anodic peak current (Ipa), scan rate, and pH were studied. The electro-catalytic activity of poly (l-Proline) MCPE towards the oxidation of ET displayed an excellent sensitivity, repeatability, reproducibility, and stability. A CV and DPV technique has been used to investigate the simultaneous determination of Ascorbic acid (AA) and Folic acid (FA) along with ET. The linear range of 6 × 10−6–6 × 10−5 M with a limit of detection (LOD) 2.2 × 10−7 M and limit of quantification (LOQ) 7.6 × 10−7 M has obtained for ET. Finally, an electrochemical method was successfully developed and applied to detect the ET. Keywords: Carbon paste electrode, l-Proline, Estriol, Cyclic voltammetry, Differential pulse, Voltammetry