Efficient voltammetric analysis for total inorganic arsenic detection in rice with enhanced sensitivity and selectivity.

A rapid, simple, and accurate voltammetric method for quantifying total inorganic arsenic in rice was described in this work. The simplified sample pretreatment involved the addition of a mixed solution of nitric acid and L-cysteine, which facilitated the simultaneous extraction and speciation of arsenic (As(III)). To eliminate interference from complex rice matrices, magnetic composites were employed to absorb copper and other potential interference. Furthermore, As(III) was detected using linear stripping voltammetry with screen-printed electrodes modified in-situ with gold nanoparticles and L-cysteine, enhancing both sensitivity and selectivity. With this strategy, the methodology demonstrated good resistance to interference and high sensitivity, with a detection limit of 0.018 mg/kg. A comparative analysis between this method and liquid chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS) showed a good correlation with an R of 0.995. Additionally, the method was successfully applied to determine total inorganic arsenic in commercial rice samples, yielding satisfactory results.