On-Column Helium Cadmium Laser Fluorescence Detector for Open-Tubular Capillary Liquid Chromatography

Abstract

The design and construction of a true on-column fluorescence detector utilizing a helium cadmium laser as the excitation source is described. The detector linearity is demonstrated over 4.5 orders of magnitude. Detection limits for two fluorophors are determined using both 325-nm and 442-nm excitation wavelengths on borosilicate glass and fused silica capillaries. The minimum detectable amount demonstrated for riboflavin is 35 femtograms injected on column. The detection limits of the laser based detector are compared to a similar design mercury-arc lamp based detector. The relative advantages and disadvantages of each design are discussed.