Bismuth Entrapped in Mesoporous Carbon for the Simultaneous Measurement of Pb, Cd and Zn.

Here we report a Bi/mesoporous carbon modified glass carbon electrode (Bi-MC-GCE) for the detection of heavy metal ions Zn, Cd and Pb. Bi(NO3)3 was firstly entrapped into the holes of MCs by sonicating them together in solution. Then the dispersed mixture was pipetted onto the surface of GCE and left to dry. Bi(NO3)3 in the holes of MCs was reduced to metallic Bi during the process of deposition for square wave stripping analysis. The obtained Bi-MC-GCE exhibits significantly enhanced sensitivity for Zn, Cd and Pb detection compared to blank GCE, bismuth or MC alone modified GCE, which is attributed to the high specific surface area of MCs and the increased amount of entrapped bismuth as active sites for the deposition and stripping of heavy metal ions. A linearship is observed for the concentration of Zn, Cd, and Pb from 10 to 110 ppb. The relative standard deviation was 3.7% for Zn, 3% for Cd and 8% for Pb at the 90 ppb level (n = 3). The suggested Bi-MC-GCE exhibits a potential application for real water sample analysis.