An Improved Flame Ionization Detector and Associated Transport System for Liquid Chromatography

Abstract

An FID and associated transport system which eliminates the major problems in the continuous detection of organic substances separated by LC is described. Column effluent is added continuously to an endless conveyor which consists of a steel spring with a twisted steel core moving horizontally around two pulleys. The conveyor transports entrained liquid into an oven where the solvent is evaporated in a stream of nitrogen. Solutes dissolved in the column effluent remain as residues on the conveyor and are transported into a pyrolysis-burner unit where they are vaporized and/or pyrolyzed in a mixture of nitrogen and hydrogen. The products which are gaseous are combusted in the flame of the burner. The ion current produced by combustion of the organic material is amplified and recorded as a measure of the amount of solute on the conveyor. Mass sensitivity of the detector for triolein was approximately one nanogram; sensitivity for this compound chromatographed through a 1 m × 2 mm column of silicic acid was approximately 100 nanograms.