Laser induced resonance energy transfer--a novel approach towards achieving high sensitivity in capillary electrophoresis. I. Clinical diagnostic application.

Most of the procedures currently performed by capillary zone electrophoresis (CZE) with laser induced fluorescence detection requires prior derivatization. This increases cost, the turn-around-time and chances of extraneous contaminations. CZE with laser induced resonance energy transfer is demonstrated as a viable alternative for detecting non-fluorescent compounds with no prior derivatization. The feasibility of this approach is demonstrated by separating and directly detecting salicylic acid (2,4-dihydroxybenzoic acid), gentisic acid (o-methoxybenzoic acid), salicyluric acid (o-hydroxyhippuric acid) and 4-aminosalicylic acid in urine. The detection of salicylate in serum is also shown. The method is highly sensitive with detection limits in the 1.10(-7) M range. Importantly it requires no prior preconcentration or sample preparation and can be used with complex sample matrices such as serum and urine.