Simultaneous extraction of chromium and cadmium from bean samples by SrFe12O19@CTAB magnetic nanoparticles and determination by ETAAS: An experimental design methodology

In the present study, dispersive micro solid-phase extraction (DMSPE) integrated with electrothermal atomic absorption spectrometry (ETAAS) as a novel method was proposed for the simultaneous analysis of cadmium and chromium in bean samples. In this method, strontium hexaferrite (SrFe12O19) modified by cetyltrimethylammonium bromide (CTAB) along with chelating agent diethyldithiocarbamate (DDTC) were used to produce SrFe12O19@CTAB nanoparticles (NPs) as a magnetic adsorbent. This adsorbent was characterized using field emission scanning electron microscope (FESEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), and differential scanning calorimetric (DSC). Response surface methodology (RSM) based on the central composite design CCD was applied to design the experiments and study of effective factors on the extraction efficiency. The experimental parameters include pH, shaking rate, adsorbent dosage, amount of ligand, and CTAB. The detection limits for chromium and cadmium ions were 0.08 and 0.09 mu g kg(-1) under the optimal experimental conditions, with standard deviations in the range of 1.7-5% and 1.2-6%, respectively (n = 4). The linear calibration was obtained in the range of 1-150 and 1-250 mu g L-1 for chromium and cadmium ions, respectively. Also, the recovery values of all samples were found in the range of 96 to 100% and 91 to 99%.