Determination of trace moisture in hydrogen chloride gas by Karl Fischer titration

Moisture of several ppm in hydrogen chloride gas has been accurately determined by a new method using the Karl Fischer reagent, which hitherto had a limitation in accuracy because of a partial reaction with hydrogen chloride when direct titration was employed.The moisture in the sample gas was collected in a cold trap kept at about ?80 °C while the hydrogen chloride gas passed through and the frozen moisture was dissolved by pyridine-methanol (1:1) solvent. a KF Reagent of factoe: 0.35 mg H₂O/ml.Titration by the Karl Fischer reagent having the equivalency factor of, e.g., 0.5 mg H₂O/ml was carried out and the concentration of the moisture was calculated from the sample volume used.