ペーパークロマトグラフィーによる下降展開中のアルカリ金属およびアルカリ土類金属イオンに対する水銀陰極電解定量

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概要

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• A quantitative analysis by electrolysis with mercury pool cathode has been applied to alkali and alkaline earth metal ions during descending paper chromatography. In this method, I employ a mercury electrode having high hydrogen overvoltage, and so I can suppress the dark current and apply acidic developers in addition to the neutral developers.<BR>The determination obtained by this method has better sensitivity due to the measurement of the current in electrolysis for alkali and alkaline earth ions than the conductometric method with Pt-electrode which has been already reported. The reason of use of the descending development is that a rapid passing descending developer decreases the raising temperature in electrolysis and the variation of the developer's component.<BR>The D. C. voltage applied is maintained constant in the range of 3.0V to 4.0V. Mercury negative electrode is made from polymetacrylate resin, which provides a long mercury pool ditch 3×18 ×2 mm, and the surface of mercury electrode is kept fresh by constant supply of mercury. The filter paper is clamped between the flat graphite anode and above mentioned mercury pool cathode, and both are placed 35 cm below the original point.<BR>After having the paper been clamped and mercury poured to the ditch cathode, the development of chromatography is carried out.<BR>Selected developers are methanol for alkali metal ions, while ethanol or 80% (v/v) ethanol for alkaline earth metal ions.<BR>A calibration curve is ordinarily obtained from the height of the peak current by electrolysis for each separated ion during descending development. By this method, for example, sodium chloride can be measured as far as 0.058% in concentration, and 1.2 μg of Na<SUP>+</SUP> (3.0 μg as chloride) in quantity. And its deviation in current of peak is below 0.7% (the region of 350 μg as chloride <I>i.e.</I> 1.220 μg of Na<SUP>+</SUP>). Potassium chloride is measured with deviation of 0.4% for 550 μg as chloride; whereas alkaline earth metal chlorides within the region of 1550 μg are measured with deviation of 2.0±0.5%.

著者

• 筑井 俊平

  神戸市立工業高等専門学校

関連論文

• ペーパークロマトグラフィーによる下降展開中のアルカリ金属およびアルカリ土類金属イオンに対する水銀陰極電解定量
• ペーパークロマトグラフィーによる上昇展開中のアルカリ金属イオンに対する電示的定量
• ペーパークロマトグラフィーによる上昇展開中のアルカリ土類金属イオンの電示定量ならびにアルカリ金属イオンとの分離
• ペーパークロマトグラフィーにおける展開中の無機イオンに対する直流加電圧検出装置の試作

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