SummaryA detection scheme based on the post-column addition of terbium followed by sensitized luminescence detection has been developed.Two model compounds -salicylic acid and diflunisal -were separated by capillary electrophoresis in an alkaline phosphate buffer. A solution containing terbium and CTAB was added post-column via a "home-built" reactor resulting in the rapid formation of the strongly luminescent terbium-salicylic acid and terbium-diflunisal complexes in a reaction capillary. Following complexation in the reaction capillary, the 325 nm line from a HeCd laser was used to excite the analytes which efficiently transfer their energy to terbium. Resultant luminescence of terbium was linear of 2 orders of magnitude. This novel and practical system enables the detection of micromolar concentrations of diflunisal and salicylic acid -a 10-fold improvement over UV absorbance detection in the same system. Post-column addition of terbium also eliminates the problems associated with strong adsorption of the lanthanide ion to the silica walls of the separation capillary and the formation of metal-ligand complexes with different coordination numbers.

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