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Featured researches published by Tamotsu Okumura.


Journal of Chromatography A | 1975

Sintered thin-layer chromatography with flame ionization detector scanning

Tamotsu Okumura; Tetsuro Kadono; Atsumi Iso'o

Abstract Various organic compounds have been separated by thin-layer cromatography on silica gel sintered glass ceramic sticks with flame ionization detector scanning. Thermolabile or polar compounds not suitable for gas chromatography were successfully detected in amounts of 10−6-10−7 g per spot. In this method, the determination of compounds, recovery and reactivation of the sintered sticks are possible in one scanning process.


Journal of Chromatography A | 1980

Sintered thin-layer chromatography

Tamotsu Okumura

Abstract A new type of thin-layer chromatographic (TLC) plates, “sintered-glass thin-layer plates”, was prepared, the layer of which consists of silica gel, alumina, Kieselguhr or another porous adsorbent, fixed with sintered glass. These sintered plates are mechanically stable, heat- and acid resistant, and can be used in the same way as the usual laboratory-prepared or commercial TLC plates. It appears that the nature of the binder for the adsorbent particles does not essentially affect the separation process that occurs on the surface of the adsorbents. The sintered plates do not contain organic binders and are resistant to, e.g., heating after being sprayed with corrosive reagents. The developed sintered plates can be regenerated readily by soaking in cleaning solutions, washing with water and reactivating by heating. The reproducibility of chromatographic separations is further improved by recycled use of the sintered plates. It was also discovered that TLC using sintered rods with flame-ionization detection is very useful for qualitative and quantitative analyses of organic compounds. The method of preparation of the sintered plates and rods, and chromatographic separation data of various organic and inorganic compounds on these sintered materials, are presented. “Welding” mechanisms among adsorbent, binder and support, and thermal stability of the adsorbent at “welding” conditions are discussed.


Journal of Chromatography A | 1972

Thin-layer chromatography on silica gel-sintered plates

Tamotsu Okumura; Tetsuro Kadono; M. Nakatani

Abstract A new pre-coated plate for thin-layer chromatography, made from silica gel and fused glass powder mixtures, has been prepaerd. This sintered thin-layer plate contains no organic binders and is mechanically stable, heat-stable and acid-resistant, and can be used repeatedly by soaking the chromatogram in cleaning solutions with no decrease in its chromatographc activity.


Agricultural and biological chemistry | 1961

Microbial 1^|^beta;-Hydroxylation of Digitoxigenin

Yoshio Nozaki; Tamotsu Okumura


Chemical & Pharmaceutical Bulletin | 1964

STUDIES ON DIGITALIS GLYCOSIDES. XIX. MICROBIOLOGICAL TRANSFORMATION OF DIGITOXIGENIN DERIVATIVES BY ABSIDIA ORCHIDIS.

Tamotsu Okumura; Yoshio Nozaki; Daisuke Satoh


Chemical & Pharmaceutical Bulletin | 1963

Hydroxylation of Digitoxigenin Derivatives by Absidia orchidis

Tamotsu Okumura; Yoshio Nozaki; Daisuke Satoh


Chemical & Pharmaceutical Bulletin | 1963

Studies on Digitalis Glycosides. XVII. Transformation of Cardenolides by Microorganisms. (3). 1β, 7β-Dihydroxy-digitoxigenin and 5β, 7β-Dihydroxydigitoxigenin.

Hiroshi Ishii; Yoshio Nozaki; Tamotsu Okumura; Daisuke Satoh


Chemical & Pharmaceutical Bulletin | 1962

Studies on Digitalis Glycosides. XI. Isolation of Digipronin, Purpnin, and Purpronin.

Daisuke Satoh; Hiroshi Ishii; Yohko Oyama; Tamotsu Okumura


Archive | 1981

Reverse-phase thin layer chromatographic plate

Tamotsu Okumura; Tetsuro Kadono


Yakugaku Zasshi-journal of The Pharmaceutical Society of Japan | 1955

Studies on Digitalis Glycosides. On the new Glycosides

Daisuke Sato; Hiroshi Ishii; Yoko Oyama; Tamotsu Okumura

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Daisuke Satoh

Tokushima Bunri University

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