Investigation of auto-ion exchange chromatograph for ultra-micro analysis of alkali and alkaline earth metals

Use of double jet type hydrogen flame ionization detector

Abstract

A new auto-ion exchange chromatograph was designed and the hydrogen flame ionization detector was improved to be suited for the chromatograph. The improved detector has two jets for hydrogen flame as shown in Fig. 1. Salts of alkali and alkaline earth metals were evaporated in the lower flame and responses corresponding to ionization of these metals were measured in the upper flame. As each flame could be adjusted to suitable temperature for evaporation and ionization, the noise level of this double jet detector was lower than that of the single jet type {This journal, 17, 847 (1968)} and also it showed higher sensitivity and much improved linear dynamic range (Refer to Fig. 7 and Table III).
An auto-ion exchange chromatograph was composed of an ion exchange column, a motor driven turntable, a photo-electric monitor, a heater chamber for evaporation of eluate and the detector (Fig. 13). The turntable had 47 platinum sample holders. When a drop of effluent from the column fell on a sample holder, the motor began to rotate with signal from the monitor and drove turntable to rotate clockwise until the next sample holder was positioned just below the column. In this manner, a drop of effluent on the holder moved intermittently entering into the heater chamber. In the heating zone, the eluate was thorooughly evaporated only remaining a metal salt on the sample holder. When the metal salt was inserted into the evaporating flame, a response from the collector electrode was obtained and recorded. Thus the elution chromatogram was obtained. By using 1M ammonium chloride as eluate, separation and detection of sodium and cesium ions by auto-ion exchange chromatograph was carried out as shown in Fig. 17.