Assoc. Professor Biochemistry-Electrochemistry Research Unit, Schools of Chemistry and Biochemistry, Institute of Science.

Abstract

This study reports advanced automated ascorbic acid (AA) differential pulse voltammetry (DPV) at carbon nanotube (CNT)-modified pencil lead  working electrodes (PLEs). Compared to the performance of the bare equivalents, CNT-modified PLEs offered in the electrochemical 24-well microtiter plate assay noticeably improved voltammograms with the analyte current peaks appearing at lower anodic potentials and with larger amplitudes. In robotic AA calibration trials the practical cathodic peak shift and signal amplification were associated with a wider linear range and better sensitivity. In addition, when pre-recorded calibration curves were used for AA determinations in spiked model and dissolved Vitamin C tablet samples, the reproducibly gained recovery rates were very close to 100%. Apparently, the CNT sensor coating is an analytical asset for the assay and this modification is recommended, particularly when the aim is to reliably achieve a high-quality robotic AA electroanalysis on larger sample numbers.