Square wave voltammetric determination of quercetin in wine and fruit juice samples at poly (safranine O) modified glassy carbon electrode

Abstract

Poly (safranine O) modified glassy carbon electrode (poly (safranine O)/GCE) was prepared by electropolymerization of safranine O on glassy carbon electrode (GCE) for the sensitive determination of quercetin (QR). The modified electrode was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Fourier transform infrared (FTIR), UV‐visible spectroscopy and scanning electron microscopy (SEM). The electrochemical behavior of QR was studied using CV and square wave voltammetry (SWV). The results showed that the poly (safranine O)/GCE exhibited high electrocatalytic activity towards the electrochemical reaction of QR. From CV study, QR exhibited quasi-reversible behaviour with two electron-transfer through adsorption controlled process. Under the optimized experimental conditions, the calibration curve for electrochemical determination of QR at the poly(safranine O)/GCE using SWV showed a linear concentration range of 0.01 μM to 8 μM with detection limit, quantification limit and sensitivity of 0.005 μM, 0.017 μM and 16.56 μA/μM, respectively. Furthermore, the poly (safranine O)/GCE sensor showed good stability, reproducibility, repeatability, sensitivity and selectivity for QR determination. Finally, the proposed method was successfully applied for the determination of QR in wine and fruit juice samples with satisfactory percentage recovery of 90.7 to 105.5% and relative standard deviation of 0.65 to 6.5%. The validity of the developed method was confirmed by comparing the results with those performed through high-performance liquid chromatography (HPLC) and results were consistent with values obtained from HPLC.