Solid-phase extraction of trace amounts of beryllium(II) from natural water samples on a glass-fibre filter followed by solid-phase spectrophotometric determination using Chromazurol B

Abstract

A selective and sensitive method for the determination of beryllium(II) is described, based on the combined use of solid-phase extraction on a glass-fibre filter (GFF) and solid-phase spectrophotometry using Chromazurol B (CAB). In solid-phase spectrophotometry, beryllium(II) is fixed and determined directly on a membrane filter as the Be^II–CAB complex formed in the presence of hexadecyltrimethylammonium bromide. The detection limit is 0.4 ng for 30 cm³ of sample solution. Trace amounts of beryllium(II) in aqueous sample solutions are first extracted on a GFF from a solution containing ethylenediaminetetraacetic acid as a masking agent of co-existing ions at pH 9.5, then determined after desorption from the GFF with 30 cm³ of 0.1 mol dm^–3 hydrochloric acid. A recovery of 96.3% is achieved. The proposed method was applied to river water and hot spring water samples with pH values in the range 1.6–3.6 using 3.0–50.0 cm³ of sample solution. The concentrations of beryllium(II) found were in the range 0.12–3.52 ppb.