Trace stripping voltammetric determination of quercethi at quercetin self-assembled monolayer (SAM)/carbon paste electrode

A new method was developed for determination quercetin (Qu) based on their adsorptive stripping voltammetric response at a carbon paste electrode (CPE) modified with a quercetin self-assembled monolayer (SAM). A stable quercetin modified electrode was prepared and its electrochemical behaviour was investigated voltammetrically. In 0.2 M phosphate buffer solution (pH 2.14) quercetin exhibits a sensitive anodic peak at around 0.55 V (vs SCE) at the SAMQu/CPE electrode. The stability of the quercetin SAM/carbon paste modified electrode is very good. The quercetin self-assembled monolayer is an effective surface for the oxidation of quercetin. Quercetin does not interfere with ascorbic acid at the modified electrode. After optimizing the parameters such as pH value, preconcentration time, and preconcentration potential, a novel electrochemical method is simple, fast, sensitive, and can used to determine quercetin with high accuracy. Under the optimal experimental conditions, the anodic peak current is linear with quercetin concentration in the range of 1.0 to 18.0 mu M. The detection limit was evalulated to be 8.40 x 10(-7) M quercetin (r = 0.9997).