Evaluation of toxic elements in rice (Oryza sativa) commercially available in Pakistan; multivariate study

The aim of this study was to determine the level of toxic elements in rice samples. Microwave-assisted digestion method was used for sample preparation to determine the cadmium (Cd) and lead (Pb). A Plackett–Burman experimental design (PBD) was used as a multivariate strategy for the evaluation of the effects of some important variables at once. Furthermore, certain variable showed up as significant, and they were optimized by using Plackett–Burman, whereas most significant variables were optimized by 2³+ star central composite designs (CCD). The accuracy of the optimized procedure ensured by the analysis of certified reference material (CRM). Outcomes are that the highest values of Cd found in brown rice (0.0889 ± 0.0056 mg/Kg), whilst the lowest concentration was found in white rice samples 0.001 ± 0.0001 mg/Kg. There is a relatively significant differences were found between the two categories of rice samples at the p-values (P = 0.05).