Effect of a Solid Support on the Efficiency of Chromatographic Separation

2020 ◽  
pp. 95-120
Author(s):  
V.G. Berezkin
Keyword(s):  
Chromatographic Separation ◽  
Solid Support

DETERMINATION OF MICRO-AMOUNTS OF 5β-PREGNAN-3α-OL-20-ONE IN URINE USING INFRARED-SPECTROMETRY

1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen
Keyword(s):  
Infrared Spectrum ◽  
Quantitative Determination ◽  
Acid Hydrolysis ◽  
Chromatographic Separation ◽  
Pure Form ◽  
Infrared Spectrometry ◽  
Hydrolysis Of

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.

Reagents for detection of carboxylate anion ligands after chromatographic separation of zinc carboxylato complexes

2003 ◽  
Vol 16 (4) ◽  
pp. 286-288 ◽  
Author(s):  
Andrej Oriňák ◽  
Monika Ádámová ◽  
Ladislav Halás ◽  
Peter Tomčík ◽  
Martina Justinová
Keyword(s):  
Chromatographic Separation ◽  
Carboxylate Anion

Interpretation of the mechanisms of chromatographic separation on CN-silica. Part I: TLC of metal complexes

2002 ◽  
Vol 15 (5) ◽  
pp. 341-344 ◽  
Author(s):  
Helena Majstorović ◽  
Živoslav Tešić ◽  
Dušanka Milojković-Opsenica
Keyword(s):  
Metal Complexes ◽  
Chromatographic Separation

Interpretation of the mechanisms of chromatographic separation on CN-silica. Part II. TLC of some phenols

2004 ◽  
Vol 17 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Helena Majstorović ◽  
Danijela Ratkov-Žebeljan ◽  
Živoslav Tešić ◽  
Dušanka Milojković-Opsenica
Keyword(s):  
Chromatographic Separation

Ketones from Nickel-Catalyzed Decarboxylative, Non-Symmetric Cross-Electrophile Coupling of Carboxylic Acid Esters

2019 ◽  
Author(s):  
Jiang Wang ◽  
Brian P. Cary ◽  
Peyton Beyer ◽  
Samuel H. Gellman ◽  
Daniel Weix
Keyword(s):  
Carboxylic Acid ◽  
Solid Support ◽  
Reaction Conditions ◽  
Decarboxylative Coupling ◽  
New Strategy ◽  
The Cross ◽  
Acyl Donors ◽  
Acid Esters

A new strategy for the synthesis of ketones is presented based upon the decarboxylative coupling of N-hydroxyphthalimide (NHP) esters with S-2-pyridyl thioesters. The reactions are selective for the cross-coupled product because NHP esters act as radical donors and the thioesters act as acyl donors. The reaction conditions are general and mild, with over 40 examples presented, including larger fragments and the 20-mer peptide Exendin(9-39) on solid support.

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