ESI-MSによるモリブデン青法における錯体生成反応の解析

• 高橋 茉莉子

  東京海洋大学大学院海洋科学技術研究科海洋環境保全学専攻

• 田中 美穂

  東京海洋大学大学院海洋科学技術研究科海洋環境保全学専攻

書誌事項

タイトル別名

• Analysis of Complex-formation Reaction in Molybdenum Blue Method by ESI-MS
• ESI-MS ニ ヨル モリブデンアオホウ ニ オケル サクタイ セイセイ ハンノウ ノ カイセキ

抄録

JIS K 0102 defines Molybdenum Blue Method as a spectrophotometric determination of phosphate. Molybdo antimonyl phosphate is formed by the reaction of phosphoric and molybdic acids and potassium antimonyl tartrate, which is then reduced by ascorbic acid. The absorbance of the reduced form of molybdo antimonyl phosphate has been known to be higher than those of other complexes. However, the reaction system of the Molybdenum Blue method and the structure of molybdo antimonyl phosphate have not been elucidated so far. To investigate the reaction system and structure, phosphoric and molybdic acids and their derivatives were monitored using electrospray ionization mass spectrometry (ESI-MS) at each reaction step in the procedure. In earlier reports, [PSb₂Mo₁₀O₄₀]³⁻ (m/z 625) was considered to exist as molybdo antimonyl phosphate, but in our studies with ESI-MS this complex was not observed. In a sample solution, a peak at m/z 1033 was identified as [PSb₂Mo(VI)₇Mo(V)₅O₄₀]²⁻; this complex was formed by the addition of both ascorbic acid and potassium antimonyl tartrate. Also, reports suggest [PSb₂Mo₁₀O₄₀]³⁻ (m/z 625) to be first formed and reduced by ascorbic acid. According to our observation by ESI-MS, the formation of molybdophosphate was completed and followed by reduction with ascorbic acid. After reduction, antimony would be attached to the reduced molybdophosphate complex. The complex [PSb₂Mo₁₂O₄₀] is considered neither to be formed in gas-phase nor to be derived from precursors in the solution, but exists as a stable complex. We have thus illustrated that ESI-MS is a useful tool that can be applied to study reactions and metal complexes in solution.

収録刊行物

• 分析化学

  分析化学 61 (12), 1049-1054, 2012

  公益社団法人 日本分析化学会

キーワード

• molybdenum blue method
• electro spray ionization mass spectrometry
• molybdophosphate
• molybdo antimonyl phosphate
• complexation

詳細情報

• CRID: 1390282679638684032
• NII論文ID: 10031131689
• NII書誌ID: AN00222633
• DOI: 10.2116/bunsekikagaku.61.1049
• COI: 1:CAS:528:DC%2BC3sXlvVequw%3D%3D
• NDL書誌ID: 024185910
• ISSN: 05251931
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I024185910
• Web Site: https://www.jstage.jst.go.jp/article/bunsekikagaku/61/12/61_1049/_pdf
• 本文言語コード: ja
• データソース種別:
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  • NDL
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  • KAKEN
• 抄録ライセンスフラグ: 使用不可