Phenosafranine integrated sulfonic acid-functionalized multi-walled carbon nanotubes for Cr(VI) detection

This work presents the electroanalytical detection of hexavalent chromium, Cr(VI) using glassy carbon electrode modified with phenosafranine (PS⁺) ion exchanged on sulfonic acid-functionalized multi-walled carbon nanotubes (MWCNT-SO₃H) i.e., MWCNT-SO₃^--PS⁺ as an electrochemical sensing platform (ESP). The prepared material, MWCNT-SO₃^--PS⁺ is assessed using various physiochemical characterization techniques for the successful ion exchange of PS⁺ onto the MWCNT-SO₃H. The electrochemical viability of PS ⁺ for the electrocatalysis at the prepared ESP is tested using cyclic voltammetry. The ESP shows high sensitivity and selectivity towards Cr(VI) determination in the presence of several possible interferences with a limit of detection of 0.36 μM. Water samples from two sources are utilized for the real sample analyses showing a high recovery percentage with acceptable average relative standard deviation values. The proposed ESP exhibits high operational stability and storage stability with negligible change in current for more than a month.