A RAPID AND EFFECTIVE SENSOR MODIFIED WITH MULTI-WALLED CARBON NANOTUBE- N1-(3-TRIMETHOXYSILYLPROPYL)-DIETHYLENETRIAMINE AS ELECTROCHEMICAL PLATFORM FOR DETECTION OF CATECHIN

Catechin (CAT) is a natural flavonoid well known for its antioxidant properties and help prevents health issues, however, its excessive intake is associated to higher health risks, therefore its accurate quantification is imperative [1]. However, unmodified electrochemical sensors present low electrochemical performance due to surface properties, therefore, modifications are used to enhance these properties, resulting in higher performance [2]. Thus, this work proposes the development of a novel screen-printed electrode based on beeswax (SPEW) modified by dropcasting MWCNT – N¹-(3-trimethoxysilylpropyl)-diethylenetriamine/chitosan for detection of CAT. The electrode was named SPWE/ MWCNT-TMSPEDTA@Chi. The study of graphite ink variation were performed using CV in 1.0 mmol L^-1 Fe(CN)₆^3-/4 at  0.1 mol L^-1 KCl, demonstrating that the adhesion of 3 layers of 70:30% of graphite:varnish obtained the best electrochemical responses to the reversibility criteria. The studies were carried out by differentiate pulse voltammetry using CAT 200 µmol L^-1 in 0.1 mol L^-1 PBS at pH 3.0 to 9.0, reaching highest current value of 16.88 µA in pH 7.0. According to the linearity (pH versus E/V), it is observed that the CAT presents mechanism corresponds to the same number of protons and electrons. Regarding the detection of CAT, the concentration range studied was 0.5 µmol L^-1 to 100.0 µmol L^-1, obtaining limit of detection of 0.3 µmol L^-1. The SPWE/MWCNT-TMSPEDTA@Chi is a promising sensor and demonstrated potential for detection of CAT in different samples, with a recovery level close to 105%.