Fast and effective assessment of 4-chlorophenol as a persistent organic pollutant (POP) using a multi-walled carbon nanotube-modified screen-printed carbon electrode (C/MWCNT-COOH/SPCE)

In this study, a rapid, precise, and targeted electroanalytical method was developed for the trace determination of 4-chlorophenol (4-CP). The study reports the use of cyclic voltammetry (CV) to characterize the electrochemical response of 4-CP and the optimization of differential pulse voltammetry (DPV) settings for its sensitive quantification. Screen-printed carbon electrodes (SPCEs) were selected for the sensitive detection of 4-CP using DPV. The incorporation of multi-walled carbon nanotubes functionalized with carboxyl groups (MWCNT-COOH) as a modifier on the working SPCE significantly enhances the electrode's performance, resulting in a 5-fold increase in sensitivity compared to that of the unmodified SPCE. Under optimal conditions, oxidation peak current exhibited a detection limit of 9.2 nM and was proportional to 4-CP concentration in the range of 0.01-1.3 μM. Additionally, the constructed sensor demonstrated high stability, high selectivity, good reproducibility, and excellent feasibility. These findings suggest that the C/MWCNT-COOH/SPE offers a simple, rapid, and cost-effective method for the prospective online assessment of 4-CP in various samples with different matrices.