Ultrasensitive electrochemical detection of caffeic acid based on boronic acid-diol recognition

An electrochemical sensor was constructed for the determination of caffeic acid (CA) based on poly(3-aminophenylboronic acid)/carboxylated multi-walled carbon nanotubes-chitosan/carboxylated graphene-β-cyclodextrin (PAPBA/c-MWCNT-CS/CG-β-CD) nanocomposites modified electrode. First, c-MWCNT-CS and CG-β-CD were deposited on the gold electrode (Au) surface by chronoamperometry in turn, and then PAPBA was electropolymerized by cyclic voltammetry to construct the proposed modified electrode. CA was recognized by PAPBA based on boronic acid-diol recognition, which could be determined by square-wave voltammetry utilizing potassium ferricyanide as a redox probe. Under the optimal experimental conditions, the PAPBA/c-MWCNT-CS/CG-β-CD-based electrochemical sensor had an ultra-wide linear response range (1.0 × 10^-13 M-1.0 × 10^-4 M) and an ultra-low detection limit (1.6 × 10^-15 M) to CA with excellent reproducibility, good short-time stability, and high selectivity. Moreover, this sensor was further used to determine CA in wine and tartary buckwheat samples with satisfactory recovery results, which offered a promising approach for determining the content of CA in foods.