Application of the modified carbon paste electrodes for determination of catechin

Abstract

Catechin is a flavonoid compound with polyphenolic structure naturally occurring in plants, fruits, tea, red wine and cacao products. Many beneficial effects are associated with catechin consumption such as antioxidant, anticarcinogenic, anti-inflammatory, antiatherogenic, antibacterial and antiviral activity. Determination of catechin is typically based on the use of high-performance liquid chromatography, but also methods such as spectrophotometry and capillary electrophoresis are reported. In this work we investigated the use of different modifications of a carbon paste electrode (CPE) for voltammetric determination of catechin. The reason for introducing a modifier into the carbon paste was to increase the sensitivity of the voltammeircic techniques, due to the catalytic effect of the modifier on the electrode processes. Multi-walled carbon nanotubes (MWCNTs), antimony(Ill) oxide and bismuth nanoparticles are investigated as bulk modifiers for preparation of CPE with concentration of 5% (w/w). Electroanalytical measurements are performed in 0.1 M phosphate buffer pH 7.0 using cyclic voltammetry and square wave voltammetry, in the concentration range from 1 to 20 mg/dm* of catechin. Two oxidation peaks of catechin are observed for all studied modified CPEs and bare CPE, with significantly higher intensity of the first peak. The results also showed improvement of sensitivity by using the modified CPEs in comparison to unmodified CPE. The application of MWCNTs as a modifier contributed to the highest sensitivity for catechin determination in relation to the other modifiers. These preliminary results show that MWCNTs modified CPE can be used as a very sensitive sensor for catechin determination in real samples.