Streaming current detector for reversed-phase liquid chromatography

Abstract

Fundamental characteristics of the electrokinetic detector for high performance liquid chromatography, whose operating principle is based on the measurement of the streaming current between both ends of a bundle of glass capillaries, were studied under reversed-phase chromatographic conditions. The detector is specifically sensitive to ionizable compounds like carboxylic acids and amines, but is also universally responsive to nonionic compounds. The detection limit for the former compounds was about 10−8 g and for the latter about 10−4 g. The lowest amount actually measured was 5.8 × 10−9 g. The universal detectability makes this type of detector unsuitable for gradient elution. The observed streaming current was in the range of 10−7 to 10−8 A and was highly dependent on the flow rate of the mobile phase. Characteristics of the detectors equipped with some packed beds prepared from porous materials instead of glass capillaries were also investigated.