Rapid analysis and sensitive detection of dl-tryptophan by using shorter capillary column coupled with deep-UV fluorescence detector

A laboratory made capillary electrophoresis (CE) system using shorter capillary column was designed and constructed in our research group. This promising CE system was then connected with confocal fluorescence microscopy which was also developed in our research group. In order to show the applicability of this new system on chiral separation of dl-tryptophan (dl-Trp), studies were undertaken using cyclodextrins (CDs) and their derivatives; sulfated (S-CDs) and highly sulfated cyclodextrins (HS-CDs) as chiral selectors. Different selector concentrations were tested at various pH levels (pH 2.5, 4.0, 6.0, 9.0) to optimize the separation conditions. The best results were achieved at lower pH values (e.g. pH 2.5 and pH 4.0). HS-β-CD and HS-γ-CD were found to be the most effective chiral selectors with a shorter retention time at low selector concentrations.