Abstract

Inorganic arsenic was determined in samples of natural water from Region II of Chile, using a methodology consisting on microwave assisted distillation and hydride generation atomic absorption spectrometry (HG-AAS). The analytical features of the method are as follows: detection limit, 5 µg l⁻¹; precision (RSD), 5%; and recovery, 93 ± 3% for As(III) and 95 ± 9% for As(V). The inorganic arsenic concentrations varied within the range 0.95–13.08 mg l⁻¹. The concentrations of inorganic arsenic obtained by microwave assisted distillation and HG-AAS, compared with the concentrations of As(III) + As(V) obtained by anion exchange chromatography coupled to HG-AAS, showed no statistically significant differences. The use of microwave assisted distillation and HG-AAS provides a simple, inexpensive way of isolating inorganic arsenic from water matrices that may otherwise cause interferences if analysed directly by HG-AAS.