The Gas Chromatographic Analysis of Low Concentrations of Barbiturates Using an Electron Affinity Detector

Abstract

To date, the problems associated with the analysis of sample concentrations less than one microgram per one microliter injection have not been critically evaluated nor have realistic detection limits been established, because of the adsorption of these barbiturates by the solid support. For samples between 1–10 micrograms, linear relationships were reported to exist between concentration and peak height or area measurements. Below one microgram levels, data are virtually non-existent. It is the purpose of this paper (a) to show that free barbituric acids can be analyzed by electron affinity detection at concentrations of 0.1–0.8 micrograms per one microliter of solution injected, (b) to compare the sensitivity of electron affinity and flame ionization detectors for several of the barbiturates under similar chromatographic operating conditions and (c) to present some data relative to the adsorptivity of these materials by the column solid support.