ｐＨ標準液の安定性

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書誌事項

タイトル別名
  • On the stability of the pH standard solutions
  • pH ヒョウジュンエキ ノ アンテイセイ

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抄録

Recent demands for method and standards for the accurate measurement of acidity and alkality have stimulated interestest in the meaning of the pH scale so widely used today. Most of commercial pH instruments employ a cell composed of a glass electrode (with inner reference) and a calomel electrode. For very accurate pH measurements, frequent calibrations of pH instruments are necessary. This requires a reliable reference buffer, the pH of which has been determined previously with great accuracy. Five standard solutions serve to fix the JIS Z 8802 conventional activity scale of pH from 0 to 95°C. The standardization of a buffer solution is accomplished by measuring the electromotive force of cell with liquid junctions of the follow type; Pt; H2(gas), primary standard|satd. KCl|buffer X, H2(gas); Pt This primary standard is 0.05 mol l-1 potassium hydrogen phthalate solution. It is defined as pH 4.000 at 15°C. This present study has two objects. The one was to inspect commercial pH reagents for pH measurement with hydrogen electrode, and the second was to confirm the change or unchange of pH value during the storage in polypropylene bottle. All reagent of this work, except sodium carbonate, indicated the value shown in JIS Z 8802. The pH values of tetroxalate, phthalate and phosphate standard solutions are so stable that they are not changed as long as three monthes. In a month, the pH values of borax and carbonate are gradually reduced. Therefore the borax and carbonate standard solutions cannot be stored for accurate measurements.

収録刊行物

  • 分析化学

    分析化学 28 (7), T39-T42, 1979

    公益社団法人 日本分析化学会

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