Improved solid-phase spectrophotometry for the microdetermination of chromium(VI) in natural water
Sulistyo Saputro1, Kazuhisa Yoshimura, Shiro Matsuoka
1Department of Mathematics and Natural Science Education, Faculty of Teacher Training and Education Sciences, Sebelas Maret University, Surakarta-57126, Indonesia.
Abstract:
A simple and sensitive solid-phase spectrophotometry procedure was improved for the microdetermination of Cr(VI). A 0.06 cm3 portion of a cation exchanger, Muromac AG 50W-X2, was used to concentrate the target Cr(VI) in a 20 cm3 water sample, and resin beads were introduced in a flow cell of 1.5 mm diameter and having a 10 mm light path length for measurements using a UV-visible spectrophotometer. Three lenses were used for focusing the incident light beam and for recovering light scattered by the solid phase in the cell. The sensitivity achieved was higher by a factor of 277 compared with that of the solution method, and the detection limit was 0.014 microg dm(-3). The recovery on spiked real water samples by the standard addition method was 96-101%. Favorable working and performance characteristics made it possible to directly determine sub-microg dm(-3) amounts of Cr(VI) in natural water samples.
