Simultaneous determination of selenium and arsenic contents in different extracts of Radix Astragali by enhancement effect of ethanol in hydride generation-inductively coupled plasma-atomic emission spectrometry

A new method was developed for simultaneous determination of trace arsenic and selenium in different extracts of Radix Astragali by enhancement effect of ethanol in hydride generation-inductively coupled plasma-atomic emission spectrometry (HG-ICP-AES) with a microwave digestion system. The effects of the concentration of the hydride generating reagent (NaBH(4)), ethanol concentration, different extraction methods and pre-reducing reagents on selenium and arsenic emission intensity were discussed and optimized. The contents of selenium and arsenic in different extracts (polysaccharide, amino acid, astragaloside, and water decoction,) in Radix Astragali were analyzed. The proposed method was validated by the use of two plant reference samples {poplar leaf (GBW07604) and tea (GBW07605)}. The detection limits (3 sigma) were 7.0 ng L(-1) and 2.0 ng L(-1) for Se(IV) and As(III) and relative standard deviations. (RSD) were 1.8% and 2.3%, respectively. The determination of Selenium and Arsenic contents in different extracts of Radix Astragali would provide useful information for the quality control of Radix Astragali. (C) 2007 Elsevier B.V. All rights reserved.