Enhanced voltammetric response of monosodium glutamate on screen-printed electrodes modified with NiAl layered double hydroxide films

Abstract

Cyclic voltammetry preliminary studies carried out on commercial carbon screen-printed electrodes (SPEs) confirmed an irreversible reduction process of glutamate in aqueous solutions of monosodium glutamate (MSG). Modified carbon SPEs coated with Ni3Al-CO3 layered double hydroxide (NiAl-LDH) film were prepared by pulse laser deposition (at 1064, 532, 355 and 266 nm wavelength). Also, carbon electrodes were covered with NiAl-LDH film and NiAl LDH + graphene composite film by matrix assisted pulsed laser evaporation (at 266 nm). Both prepared LDH powder used as laser target and LDH films were characterized by XRD. LDH and LDH-composite films were characterized by FTIR spectroscopy, SEM, AFM and contact angle measurements. All cyclic voltammograms recorded at 0.08 V/s on bare carbon screen-printed electrode and modified electrodes coated with different LDH films exhibited a linear dependence for cathodic peak current vs. MSG concentration. Compared to the slope value (2.563±0.262 μAcm−2μM−1) obtained in the case of bare carbon screen-printed electrode, the sensitivity performances of the modified electrodes were substantially increased. The best results were recorded under optimum conditions for graphene composite film, namely a value of 8.567±0.565 μAcm−2μM−1. Cyclic voltammetry tests of modified electrodes prepared by laser technique with addition of radiofrequency plasma indicated a negative effect on surface electroactivity, with drastically reducing the quality of MSG cathodic voltammetric signal.