A simple and effective graphene oxide-zinc oxide nanocomposite based solid phase extraction method for the determination of cadmium in tea matrix at trace levels by flame atomic absorption spectrophotometry

In this study, an easy, environmentally friendly and fast approach was introduced for the synthesis of GO-ZnO nanocomposite (NC). Characterization tools including X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to verify the synthesized nanomaterial. Afterward, the combination of GO-ZnO NC based dispersive solid phase microextraction (dSPME) and flame atomic absorption spectrophotometry (FAAS) was used to preconcentrate and determine Cd with high precision and accuracy. In the optimization experiments, all parameters that affecting extraction yield were optimized. Limit of quantification (LOQ) and detection (LOD) values for the GO-ZnO NC-dSPME-FAAS system were calculated as 12.76 mu g L-1 and 3.83 mu g L-1, respectively. In order to check the applicability and accuracy of the developed method, recovery experiments were performed on three different hibiscus tea samples. The percent recovery values calculated from the spike experiments were in the range of 84 - 111%.