Electrochemical laser induced breakdown spectroscopy for enhanced detection of Cd(II) without interference in rice on layer-by-layer assembly of graphene oxides

Rice is considered to be one of the dominant sources of exposure to Cd(II) for human being, thus monitoring the concentration of Cd(II) in rice is very important. The anti-interference ability for several current approaches (especially electrochemical method) is expected to be dramatically improved due to more extreme complicated conditions in real rice sample. Here, a methodology combined electrochemistry with laser-induced breakdown spectroscopy (EC-LIBS), as well as choice of negatively charged graphene oxides (GO(-)), was selected for the determination of trace Cd(II) in rice. In this method, the target Cd(II) was preconcentrated on the surface of GO(-) modified Ti plate in the form of Cd(0) by electrochemcial deposition, the succeeding elemental identification and quantification was achieved using LIBS. Electrochemcial deposition and the modification of GO(-) on electrode significantly increased the sensitivity of the Cd(II) analysis in rice utilized LIBS only (for the same mass of rice sample) by 3 orders of magnitude and a ppb-level limits of detection (LOD) was obtained. Good anti-interference ability was also achievable during the actual measurements, particularly when Cu(II) and Mn(II) co-existed. The combination of electrochemistry and LIBS techniques, as well as the presence of GO, made it very attractive for the purposes of Cd(II) sensing in standard and nonstandard conditions.