Radionuclide and metal ion detection on a capillary electrophoresis microchip using LED absorbance detection

The sensitive and selective detection of various radionuclide, lanthanide and transition metal cations on a capillary electrophoresis (CE) microchip is demonstrated using two different metallochromic complexation ligands, 4-(2-pyridylazo) Resorcinol (PAR) and Arsenate III (AIII). In order to take advantage of the compact and portable potential of a CE microchip, LED absorbance detection was investigated on a simple cross pattern microchip with two different microchannel depths, 20 and 100 mum. Micellar electrokinetic chromatography (MEKC) was utilized on a glass microchip to resolve up to seven different PAR-metal chelates with sub-ppm detection limits within a minute. Microchip determinations of U(VI) were performed using the colorimetric metal complexation ligand, Arsenate III, utilizing absorbance detection with a red LED light source and a photodiode array detector. A mixture of UO22+ and three interference metal ions were separated on a microchip, and the addition of EDTA to the background electrolyte (BGE) is demonstrated to be an effective means of eliminating any interference from lanthanide and transition metal ions. Published by Elsevier Science B.V.