Highly sensitive determination of hesperidin using electrode modified with poly(ferulic acid)

Hesperidin is a major phenolic antioxidant of the orange fruits and responsible for their positive health effect. It is used as part of therapy of blood vessel conditions. Methods for hesperidin quantification are of practical interest. Recently, several voltammetric approaches have been developed for hesperidin quantification. Nevertheless, the analytical characteristics could be improved. To solve this problem, glassy carbon electrode modified with multi-walled carbon nanotubes and poly(ferulic acid) has been developed. Polymeric coverage has been obtained electrochemically under potentiodynamic conditions. Their optimization based on the hesperidin voltammetric response has been performed. Poly(ferulic) layer has to be obtained from 250 µM monomer solution in 0.1 M NaOH by fifteen potential scans from -0.2 to 1.0 V with the scan rate of 100 mV s^-1. Hesperidin oxidation currents are 2.8-fold increased at the polymer-modified electrode vs. carbon nanotube-based electrode at the same oxidation potential. Differential pulse voltammetry in phosphate buffer pH 5.5 has been used for the quantification of hesperidin. Linear dynamic ranges of 0.025-1.0 µM and 1.0-10 µM has been achieved with the limits of detection and quantification of 7.0 and 23.4 nM, respectively. The analytical characteristics obtained are the best ones reported to date.