Activated Hordeum vulgare L. dust as carbon paste electrode modifier for the sensitive electrochemical detection of Cd²⁺, Pb²⁺ and Hg²⁺ions

Hordeum vulgare L. dust (HVW) chemically activated using Na₂CO₃ (HVW-Na₂CO₃) was characterised by several techniques (SEM, FTIR and TGA/DTG). The increase in the surface charge of the biomaterial induced by the activation process was demonstrated by multisweep cyclic voltammetry. The modified HVM was then exploited as carbon paste electrode (HVW-Na₂CO₃/CPE) modifier to prepare a sensor which was applied in the determination of Cd²⁺, Pb²⁺ and Hg²⁺at trace level by stripping voltammetry. Key experimental variables (nature of stripping medium, modifier mass in CPE, electrolysis time and potential and pH of preconcentration solution) were optimised to detect Cd²⁺, Pb²⁺ and Hg²⁺ at HVW-Na₂CO₃/CPE. Under optimised conditions, calibration plots were obtained for all analytes. The low limits of detection (3s/m) were found to be 1.82 nM, 0.0691 nM and 0.237 nM for Cd²⁺, Pb²⁺and Hg²⁺respectively. The sensor was successfully applied to the detection of trace metals in real samples.