Electrochemical determination of indigo carmine in food and water samples using a novel platform based on chiral amine-bis(phenolate) boron complex

Abstract

For the electrochemical determination of indigo carmine (Ic), which is a common and toxic dyestuff, a nanocomposite (LB/MWCNTs) was prepared with chiral amine-bis(phenolate) boron complex containing N, N-Diethyl-p-phenylenediamine (LB), and multi-walled carbon nanotubes (MWCNTs). Chiral amine-bis(phenolate) boron-based electrochemical sensor (LB/MWCNTs/GCE) was designed by modifying the glassy carbon electrode with LB/MWCNTs composite and characterized by scanning electron microscope (SEM) and Fourier transforms infrared spectroscopy (FT-IR). Cyclic voltammograms of bare GCE, LB/GCE, MWCNTs/GCE, LB/MWCNTs/GCE electrodes in neutral ferrocene, cationic Ru(NH3)6+3, and anionic Fe(CN6)−3 probes were recorded. Also, their electrochemical behavior was evaluated by comparing with the theoretical values calculated in the Randles Sevcik equation. The active surface areas of bare GCE and LB/MWCNTs/GCE electrodes were found to be 1.039 cm2 and 2.401 cm2, respectively. LB/MWCNTs nanocomposite showed a high electrocatalytic activity on the electrochemical behavior of Ic in pH 2.0 phosphate buffer solution. A very low detection limit (0.019 μM) and linearity over a wide linear range (0.1 μM–30.0 μM) were obtained for Ic using square-wave voltammetry. Chiral amine-bis(phenolate)boron-based electrochemical sensor performance was examined in real samples such as river water, tap water, orange juice, and candy-coated chocolate. The results revealed that the chiral amine-bis(phenolate) boron-based electrochemical sensor can be successfully used as an alternative to the existing analytical techniques used for the quantification of Ic.