USO DO SISTEMA DE ANÁLISE POR INJEÇÃO EM BATELADA E CDTRODO PARA DETERMINAÇÃO DE QUERCETINA

Abstract

Quercetin belonging to the group of flavonoids and has in its structure the catechol group, thus, it contains antioxidant properties important for living beings’ organism. Thus, this antioxidant has gained prominence in pharmaceutical and medicinal research precisely because of its ease in donating electrons to other molecules, especially those that act in the human body, preventing various diseases such as cancer, inflammation, cytoxicity, among others. Quercetin in its natural and pure form has a very intense yellowish color, then contributes to pigmentation in most foods in which it is found. In the beak pepper it can be extracted using ethanol as a solvent due to its polar property. As currently studies prove the efficacy of plant extracts in their antifungal and antimicrobiological action, it is also important to quantify its antioxidant properties, especially for medicinal use in living beings. The work described here involves the study and development of an electrochemical technique using Batch Injection Analysis (BIA) with chronoamperometric detection and gold CD electrode as the working electrode. This technique was studied to propose a new methodology for determining and quantifying quercetin in ethanolic extracts of pepper var. beak (CapsicumChinense). Electrochemical analyzes were performed with Britton Robinson pH 10 buffer, as support electrolyte and potential equal to +1.0 V. All analyzes were performed without agitation and with the potentiostat μAuto Lab Type III. For simultaneous injections, the electronic micropipette was used. The experiments performed obtained good stability (DPR = 3.25% and 7.53%), linearity (R = 0.9893), high analytical frequency (~ 150 injections h-1) and with detection limit in the order of 5.25 ng mL-1. These values, when compared to other studies, demonstrated that the methodology proposed here can be used as a simple and low-cost alternative for the quercetin determination in pepper extracts.