Facile and green fabrication of electrochemical sensor based on poly(glutamic acid) and carboxylated carbon nanosheets for the sensitive simultaneous detection of Cd(II) and Pb(II)

This work describes the development of a simple, effective, and sensitive electrochemical sensor based on a glassy carbon electrode (GCE) modified with carboxylated carbon nanosheets (cCNSs) and poly(glutamic acid) (PGA) for the simultaneous detection of trace amount of Cd(II) and Pb(II) by differential pulse anodic stripping voltammetry (DPASV). The cCNSs were introduced to increase the effective surface area and electron transport efficiency of the sensor, while PGA acting as a capturer could capture target metal ions and eventually enhance the selectivity and sensitivity in the detection of Cd(II) and Pb(II). The designed sensor showed a linear range of 1.0–100.0 μg/L for both metal ions, with detection limits (S/N = 3) of 0.13 μg/L for Cd(II) and 0.15 μg/L for Pb(II), respectively. The sensor was applied to the simultaneous detection of Cd(II) and Pb(II) in the water and rice samples, and the results were in good agreement with those obtained by graphite furnace atomic absorption spectrometry (GFAAS). It also gave excellent performance with regard to its selectivity, recovery, stability, and reproducibility.