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 BeII–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.