Graphene-carbon paste electrode for cadmium and lead ion monitoring in a flow-based system

An environment friendly electrode for determining Cd(2+) and Pb(2+) levels in an automated flow system was successfully developed. Cyclic voltammetry and square wave anodic stripping voltammetry (SWASV) coupled with sequential injection analysis (SIA) were employed to study the electrochemical behavior of the electrode. The in situ bismuth-modified graphene-carbon paste electrode (Bi-GCPE) exhibited excellent electrooxidation of Cd(2+) and Pb(2+) in the automated flow system with a significantly higher peak current for both metal ions compared with the unmodified CPE. The limits of detection from this method were 0.07 and 0.04 μg L(-1) for Cd(2+) and Pb(2+), respectively, with a linear oxidation peak current response for Cd(2+) and Pb(2+) in the range of 0.10-50.0 μg L(-1) under optimum conditions. The Bi-GCPE was also applied for the determination of Cd(2+) and Pb(2+) in low- (tap water) and high- (sea bass fish and undulated surf clam tissues) matrix complexity samples by automated flow system. The recoveries were acceptable and ranged from 70.4% to 120% for Cd(2+) and 65.8% to 113.5% for Pb(2+).