Microwave-assisted acid extraction of selenium from medicinal plants followed by electrothermal atomic absorption spectrometric determination.

A simple and rapid microwave-assisted extraction (MAE) of selenium (Se) from medicinal plants was investigated using different concentrations of nitric acid and hydrochloric acid, sample mass, heating time, microwave energy, and plant particle size. The optimization strategy was carried out using multivariate methodologies. Electrothermal atomic absorption spectrometry was used to determine Se. The accuracy of the optimized procedure was evaluated by using certified reference materials with certified values for Se and a microwave-assisted acid digestion (MD) method for comparative purpose. No significant difference was observed (P > 0.05) when comparing the values obtained by the proposed MAE and MD methods (paired t-test). Under the optimum operating conditions, the LOD obtained from the standard calibration curve was 0.012 microg/L for Se. The average RSD of the MAE method varied between 4.05 and 7.53% (n = 6). The proposed method was successfully applied for the determination of Se in medicinal plants used as remedies for cancerous and infection diseases.