Enhancing of methyl orange oxidation using nanotube sensor: analytical application in water

Abstract

The electrochemical properties of poly(l-asparagine) modified carbon nanotube paste electrode (PAMCNPE) were investigated for precise detection of methyl orange. Asparagine was electrochemical polymerized and deposited onto the carbon nanotube paste surface to develop the modified electrode, and comparing to the bare carbon nanotube paste electrode. Cyclic voltammetry measurements of the modified electrode at pH 7 in a 0.2 M phosphate buffer saline showed excellent oxidizing activity towards methyl orange. Various factors were studied, including the ionic strength of the buffer. The external morphology and conversion of the perception material were studied using field emission scanning electron microscopy and electrochemical impedance spectroscopy, respectively. High sensitivity and selectivity for detecting methyl orange were also achieved by optimizing experimental conditions such of pH, concentration variation, and scan rate. The concentration range spanned from 0.2 to 9.0 µM, with the lower limit of detection at 1.368 × 10^–7 M and the quantification limit of 4.562 × 10^–7 M, indicating its excellent analytical performance. Additionally, the PAMCNPE shows good stability, reproducibility, and repeatability. Its remarkable recovery in real samples underscores its potential for practical applications in environmental and clinical analysis.

Graphical abstract