Selective Determination of Total Capsaicinoids in Plant Material Using Poly(Gallic Acid)‐modified Electrode

Abstract

Novel voltammetric approach for the selective determination of total capsaicinoids has been developed using glassy carbon electrode modified with multi‐walled carbon nanotubes and poly(gallic acid) (PGA/MWNT/GCE). The modified electrode provides significant improvements in the capsaicinoids voltammetric characteristics in comparison to GCE and MWNT/GCE. The electrooxidation of capsaicinoids is irreversible adsorption‐controlled process with the anodic transfer coefficient of 0.49–0.53 and heterogeneous electron transfer rate constant of 1300–2400 s−1. The analytical ranges of 0.010–1.0 and 1.0–50 μM for capsaicin, 0.025–0.75 and 0.75–75 μM for dihydrocapsaicin and 0.025–5.0 and 5.0–75 μM for nonivamide with the detection limits of 2.9, 5.9 and 6.1 nM, respectively, have been obtained using differential pulse voltammetry (DPV). The selectivity of the capsaicinoids quantification in the presence of ascorbic acid, α‐tocopherol and carotenoids is shown. The method has been tested on the samples of red hot pepper spices and Capsicum annuum L. tinctures. The results correspond to the chromatographic data.

Electrochemical Determination of Capsaicinoids Content in Soy Sauce and Pot-Roast Meat Products Based on Glassy Carbon Electrode Modified with Β-Cyclodextrin/Carboxylated Multi-Wall Carbon Nanotubes

“…Based on previous reports [6,[15][16][17] and the above experimental results, the electrochemical reaction of capsaicin on β-GCNT was initially concluded as follows. First, capsaicin generated a new compound that was more easily oxidized and a reduction product on the β-GCNT sensor surface, which might correspond to the oxidation of the phenolic hydroxyl group or the hydrolysis of the methoxy group [6,16].…”

“…Compared with ELISA and infrared spectroscopy, electrochemical detection is recognized as a more economical and easier to miniaturize method [9][10][11][12][13]. To meet the determination of capsaicinoids content, electrochemical sensors based on carbon nanotubes (CNTs) [14,15], graphene [16,17], and nanoparticles [18] have been developed. Among them, electrochemical sensors modified with CNTs are promising candidates [19][20][21][22].…”

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

“…Another typical example is the determination of total capsaicinoids in Capsicum annuum L. tinctures using GCE modified with MWCNTs and electropolymerized gallic acid [130], or GCE with carboxylated single-walled carbon nanotubes and dispersed in cetylpyridium bromide CeO 2 nanoparticles [131]. Electrode surface modification provides an improvement in the capsaicinoids response due to the adsorption of the analytes at the electrode surface via hydrophobic interactions with polymeric coverage [130] or cetylpyridium bromide [131]. Furthermore, an increase in the effective surface area of the electrodes and electron transfer rate has been provided due to the presence of a modifier.…”

A simple and rapid electrochemical determination of pungency: Application to aqueous and ethanolic extracts of Capsicum annuum cubana red

“…But fast, simple, and inexpensive methods of food analysis are demanded. To meet these requirements, electrochemical techniques such as electrochemical sensors based on carbon nanotubes, [15][16][17][18] graphene, 19,20 functionalized graphite, 21 nanoparticles, 22 or ionic liquids 23 have been proposed. The use of a bare glassy carbon electrode without extra materials is definitely more advantageous than those requiring extra materials, as long as the sensitivity is in the needed range.…”