Hybridized sulfated-carboxymethyl cellulose/MWNT nanocomposite as highly selective electrochemical probe for trace detection of arsenic in real environmental samples

Abstract

A highly selective and ultra-sensitive electrochemical sensing probe was proposed by combining sulfated-carboxymethyl cellulose (CMC-S) and a functionalized-multiwalled carbon nanotube (f-MWNT) nano-composite with high conductivity and durability. The CMC-S/MWNT nanocomposite was impregnated on a glassy carbon electrode (GCE) to construct the non-enzymatic and mediator-free electrochemical sensing probe for trace detection of As(III) ions. The fabricated CMC-S/MWNT nanocomposite was characterized by FTIR, SEM, TEM, and XPS. Under the optimized experimental conditions, the sensor exhibited the lowest detection limit of 0.024 nM, a high sensitivity (69.93 μA nM⁻¹ cm⁻²) with a good linear relationship in the range of 0.2–90 nM As(III) concentration. The sensor demonstrated strong repeatability, with the current response continuing at 84.52% after 28 days of use, in addition to good selectivity for the determination of As(III). Additionally, with recovery ranging from 97.2% to 107.2%, the sensor demonstrated comparable sensing capability in tap water, sewage water, and mixed fruit juice. The electrochemical sensor for detecting trace levels of As(III) in actual samples is anticipated to be produced by this effort and is expected to possess great selectivity, good stability, and sensitivity.