Detection of Cadmium(II) in Water Using Colorimetric-Solid Phase Extraction 2005-01-2890
Contamination of spacecraft water by heavy metals, such as cadmium and lead, is of growing concern. As a consequence, there is need for a rapid, on-board, easy-to-use method for the determination of cadmium(II) at low ppb levels in spacecraft drinking water supplies. This paper describes the preliminary development of a method for the selective, low level determination of cadmium(II) based on colorimetric-solid phase extraction (C-SPE) [1, 2]. In C-SPE, an analyte is extracted from a water sample onto a membrane that has been previously impregnated with a colorimetric reagent, and then quantified as its colorimetric complex directly on the membrane surface using diffuse reflectance spectroscopy. Results from preliminary tests that screened the performance of 1-(4-nitrophenyl)-3-(4-phenyl-azophenyl)triazene (cadion), and organic dyes, rhodamine B, brilliant green, and methyl violet as colorimetric reagents for potential use in a C-SPE analysis of cadmium(II) are described.