A multifunctional liquid chromatographic detector

Abstract

A liquid chromatographic detector is described that monitors chromatographic column eluents simultaneously by UV absorption at 254 nm, fluorescence by excitation at 254 nm and electrical conductivity. The response of the detector has a linear range of over three orders of magnitude for each detecting function. The absolute sensitivities, defined as that concentration of solute that provides a signal to noise ratio of two, are 1.7 × 10^–7 g ml^–1 of toluene, 2.5 × 10^–8 g ml^–1 of dansylisoleucine and 5 × 10^–8 g ml^–1 of sodium chloride for JV absorption, fluorescence and electrical conductivity, respectively. The detector employs low-dispersion, serpentine tubing for column detector connections and has a cell volume of 2.2 µl. The dispersion of the detector has a standard deviation of only 2.8 µl at a flow-rate of 2 ml min^–1 and is this suitable for use with modern high-speed 3-µm columns or high mass sensitivity, low solvent consumption, small bore columns. In addition to providing a simple basic detector with increased flexibility and versatility, simultaneous monitoring on all three functions can provide added confirmation of solute identification.