SEPARATION OF TRYPTOPHAN AND RELATED INDOLES BY MICELLAR ELECTROKINETIC CHROMATOGRAPHY WITH KRF LASER-INDUCED FLUORESCENCE DETECTION

Micellar electrokinetic chromatography (MEKC) was applied for the sepa ration of tryptophan and related indoles. Using a 5 mM sodium berate b uffer (pH 9.2) containing 50 mM sodium dodecyl sulfate and 5% acetonit rile, eleven indoles were baseline separated in under 17 min. Most of the indoles were detected at the nM level by native fluorescence using KrF laser-induced fluorescence (LIF),which was approximately 100 time s more sensitive than UV absorption detection at 200 nm. Preliminary r esults show that the MEKC-LIF with direct sample injection is a feasib le method for assessing indole profiles in diluted urine and serum.