Electrochemical determination of Pb(II) in paint factory effluent and hot spring water samples using chitosan-based Schiff base modified carbon paste electrode

Pb(II) is a hazardous and non-biodegradable metal widely used in paint manufacturing and mining industries, posing health risks such as neurological disorders, kidney dysfunction, and increased blood pressure. Therefore, developing an easy, selective, and sensitive sensor for its detection is crucial. In this study, a chitosan-vanillin Schiff base (CVSB) was synthesized, and its successful formation was confirmed using spectroscopic and electrochemical techniques. Both bare and 10 % CVSB-modified carbon paste electrodes (CVSB-CPE) were employed to detect Pb(II), but the CVSB-CPE demonstrate significant electrocatalytic activity. Using an square wave anodic stripping voltammetry (SWASV) the sensor exhibited a linear response to Pb(II) ranging from 0.001 to 100 μM, with a limit of detection (LOD) of 0.57 nM. Additionally, repeatability tests showed a relative standard deviation (RSD) of 2.6 % over 17 consecutive measurements, while reproducibility across four independently prepared electrodes yielded a RSD of 1.05 %. The sensor also displayed high selectivity in the presence of potential interfering species, including Hg 2+ , K + , Cd 2+ , Na + , Ni 2+ , Fe 3+ , and Cu 2+ . The recovery tests conducted on factory effluent and hot spring water samples demonstrated a recovery ranging from 97.15 % to 113.49 % and 93.05 % to 108.01 %, respectively.