Paper Chromatographic Separation, Identification, and Determination of Diglycerols.

1964 ◽  
Vol 36 (3) ◽  
pp. 502-505 ◽  
Author(s):  
Herbert. Siegel ◽  
A. B. Bullock ◽  
G. B. Carter
Keyword(s):  
Chromatographic Separation ◽  
Paper Chromatographic Separation

scholarly journals A colorimetric micro method for the determination of formyl groups

1969 ◽  
Vol 111 (4) ◽  
pp. 401-406 ◽  
Author(s):  
S. Usha Lakshmi ◽  
L. K. Ramachandran
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Chromatographic Separation ◽  
Quantitative Method ◽  
Standard Procedure ◽  
Formyl Group ◽  
Alumina Column ◽  
Purple Colour ◽  
Paper Chromatographic Separation

The characteristic purple colour formed by N-formyl-N′-2,4-dinitrophenyl-hydrazine in the presence of piperidine and acetone was made the basis of a new quantitative method for the determination of formyl groups. Samples containing N-formyl groups (up to 0·4μmole) are hydrazinolysed at 97–98° for 1hr. and are dinitrophenylated after the removal of excess of hydrazine. Interference from 2,4-dinitrophenylhydrazine is eliminated by subjecting the dinitrophenylated samples to chromatography on an alumina column. Interference arising from the formation of N-acetyl-N′-2,4-dinitrophenylhydrazine, when determining formyl groups in samples containing acetyl, can be avoided by a paper-chromatographic separation before analysis. A standard procedure is described. The method gives satisfactory results when applied to N-formyl-amino acids. Gramicidin, when analysed by this method, was found to contain 0·89 mole of formyl group/mole for a molecular weight of 1880. The method indicated the absence of formyl groups from lysozyme, a protein known not to contain such groups. Generally, the analytical values obtained by the method are within 100±4% of theory.

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%.

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