蒸留水中の塩化物イオンの含有量と大気からの汚染 : 冷凍濃縮法の応用

概要

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By application of freeze concentration, the chloride content in distilled and redistilled waters was determined as a material characterizing the water qualities. The sample solution was carefully frozen in a polyethylene bottle with stirring, followed by the determination of chloride in the resulting concentrate. Freezing of 51 sample solution required about 8 h at -15℃ to -18℃. The concentrated solution was contaminated with chloride in the atmosphere during the procedure. The amount of chloride originally present in the sample was obtained by correcting for the contamination value determined separately as follows: After removal of the concentrated solution obtained in the first freeze concentration, the ice remained was melted and the resulting water was repeatedly concentrated several times. The average contamination level was affected not only by the conditions of ambient air but also even by the circumstances of neighbouring laboratories. In order to prevent the chloride contamination, the freeze concentration was done by using a bottle covered with a polyethylene disk with a center hole to fit the stirring shaft through it. The values of chloride obtained were lower and more reproducible than those in uncovered procedure. The average concentrations of chloride in distilled and redistilled waters were 3.6 ppb and 1.6 ppb, respectively.
社団法人日本分析化学会の論文
1981-09-05