A glassy carbon electrode modified with a bismuth film and laser etched graphene for simultaneous voltammetric sensing of Cd(II) and Pb(II)

Polyimide (PI) sheets were laser etched to obtain graphene-based carbon nanomaterials (LEGCNs). These were analyzed by scanning electron microscopy, X-ray diffraction and Raman spectroscopy which confirmed the presence of stacked multilayer graphene nanosheets. Their large specific surface and large number of edge-plane active sites facilitate the accumulation of metal ions. A glassy carbon electrode (GCE) with an in-situ plated bismuth film was modified with the LEGCNs to give a sensor with satisfactory response for the simultaneous determination of cadmium(II) and lead(II) by means of square wave anodic stripping voltammetry. It appears that is the first report on an electrochemical sensor based on the use of laser etched graphene for determination of heavy metal ions. Figures of merit for detection of Cd(II) include (a) a low and well separated working potential of −0.80 V (vs. Ag/AgCl), (b) a wide linear range (from 7 to 120 μg·L−1), and a low detection limits 0.47 μg·L−1. The respective data for Pb(II) are (a) -0.55 V, (b) 5 to 120 μg·L−1, and (c) 0.41 μg·L−1. The modified GCE displays remarkable repeatability, reproducibility, selectivity and stability. The sensor was applied to the simultaneous determination of Cd(II) and Pb(II) in spiked real water samples. The results confirm that the laser etching technique is an efficient tool for the preparation of carbon nanomaterials with high quality and great sensing performance.