燃焼・非水溶媒滴定法による一酸化炭素標準ガス及び数種のガス中の極微量の炭素化合物の定量

概要

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Microamounts of carbon compounds in argon, nitrogen, oxygen and standard gases of carbon monoxide (SRMS from NBS) were determined by a combustion-nonaqueous titrimetric method. The sample gas was oxidized with copper (II) oxide at 700℃. Then, carbon dioxide produced was absorbed with Ar N-dimethylformamide containing 5% of monoethanolamine. The absorbent was titrated with the standard benzene-methanol solution of tetra-n-butylammonium hydroxide {(0.003〜0.001)M} using thymolphthalein as an indicator. The standard solution was standardized against benzoic acid. Carbon compounds of as low as (0.2〜1) ppm (molar fraction) could be determined in argon and nitrogen. Much carbon compounds could be found in oxygen. One sample contained 6 ppm of carbon dioxide and 11 ppm of other carbonaceous materials. The results of the analysis of the standard gases from NBS were coincided excellently with its certified value for the sample of 47 ppm of carbon monoxide. The results for the sample of 9.7 ppm, however, were 0.7 ppm higher than its certificated value. Two reasons may be considered for this diserepancy. First, the gases were prepared on Nov. 1973, and analyzed here 2 years after its certified date. Secondly, because total amount of carbon compounds can be determined by this method, there may be the influence of carbon compounds in the nitrogen used as the diluent of the standard gas.
社団法人日本分析化学会の論文
1977-12-05