A method for eliminating an accidental choke against carrier gas flow in a partly exhausted carbon dioxide absorption tube

Abstract

In the simultaneous C, H and N determination apparatus involving a thermal conductivity measurement, a choking of carrier gas flow in the carbon dioxide absorption tube may cause a serious interference with the accurate quantitative analysis.Soda asbestos generally used causes the choking in the part of carbon dioxide absorption, so that a preventive method was studied. Lithium hydroxide of 1020 mesh was poor in quantity of carbon dioxide absorption, and it would not be practical, while, on the other hand, it was not given any change of form before and after the absorption.Therefore, it was mixed at a volume ratio of 1:2 or 1:1 with the soda asbestos and packed in the absorption tube with 10cm length, and good results were obtained. The capacity of the carbon dioxide absorption with the mixture was found to be reproducible for about 150 times of analyses with 2.02.5mg of acetanilide in the 1:2 ratio mixture and for 120times of analyses in the 1:1 ratio mixture and practically no change in calibration values was observed. With the similar object, polyethylene pieces of O. D.=2.3mm I. D.=1.2mm and length=23mm were also studied.All the mixtures above mentioned showed to be available to the absorption limit of reagents packed and the analytical accuracies have been illustrated in Table I.