Hydroxylation/carbonylation carbonaceous microspheres: A route without the need for an external functionalization to a “hunter” of lead(II) for electrochemical detection

Abstract

Hydroxylation/carbonylation carbonaceous microspheres (H/C CMSs) are designed as a “hunter” for lead(II) (Pb2+) in electrochemical detection. Without the need for external functionalization, the carbonyl and hydroxyl groups were introduced to the surface of carbonaceous spheres during hydrothermal synthesis using glucose. The features of H/C CMSs before and after lead adsorption were studied using FTIR and XPS. CO and OH vibrations were affected by lead adsorption, which can be attributed to the coordination bonds between oxygen atoms of CO and OH and Pb2+. A H/C CMSs modified glassy carbon electrode (GCE) was electrochemically characterized using cyclic voltammetry (CV). Anodic stripping voltammetric performance of bound Pb2+ was evaluated using square wave anodic stripping voltammetry (SWASV) analysis. Linear increases in the stripping peak current were observed for concentrations from 0 to 30nM, with a sensitivity of 1.9067μA/nM. This was almost 260 times higher than the sensitivities to Cu2+ and Hg2+. A limit of detection was found to be 2nM based on the 3σ method. The successive addition of 250nM Zn2+, Cr3+, Cd2+, Cu2+, and Hg2+ to 25nM Pb2+ acetate buffer solution did not interfere with the adsorption of Pb2+ and stripping of Pb0.