AXIAL ILLUMINATION OF FUSED-SILICA CAPILLARIES - INVESTIGATION OF FLUORESCENCE AND REFRACTIVE-INDEX DETECTION

The optical waveguide properties of fused-silica capillaries enable greater illuminated sample volume by axial illumination, as compared to cross capillary illumination. Several modes of light propagation inside these unique optical waveguides are described. A micro-LC flow cell featuring axial illumination with mobile phase elimination by nebulization has been developed and evaluated. This device was used in the construction and evaluation of laser-induced fluorescence and laser-based refractive index detectors. A summary of results from our studies and a survey of the various detection possibilities, theoretically compatible with axial illumination of capillary waveguides, are presented.