ESTIMATION OF REDUCING SUGARS IN STARCH HYDROLYZATES BY PAPER CHROMATOGRAPHY

1950 ◽  
Vol 28b (9) ◽  
pp. 527-534 ◽  
Author(s):  
Ping Shu
Keyword(s):  
Quantitative Determination ◽  
Paper Chromatography ◽  
Chromatographic Separation ◽  
Reducing Sugars ◽  
Reducing Power ◽  
Probable Error

A method for quantitative determination of glucose, maltose, and reducing dextrins in starch hydrolyzates is described. The components are separated by paper chromatography and determined colorimetrically by measurement of their reducing power with alkaline copper and arseno-molybdate reagents. The probable error of the determinations with the use of this method is about 2%. A compact apparatus was designed, suitable for handling a large number of samples in the chromatographic separation. It is particularly useful for compounds with low Rf values.

Determination of Glucose in Egg Solids by Paper Chromatography

1964 ◽  
Vol 47 (3) ◽  
pp. 594-596
Author(s):  
Charles H Coleman ◽  
John E Despaul ◽  
Santiago Ruiz
Keyword(s):  
Quantitative Determination ◽  
Paper Chromatography ◽  
Chromatographic Method ◽  
Reducing Sugars ◽  
Residual Glucose ◽  
Reduction Methods ◽  
Egg Albumen

Abstract Copper reduction methods for determining residual glucose in egg solids give high apparent values due to the presence of other reducing sugars. A paper chromatographic method specific for glucose in dried egg and egg albumen has been developed in which glucose migrates independently of other components. Micro-quantities of glucose in egg from which glucose has been removed can be readily detected and determined. Migration of the unknown and its comparison with a standard glucose spot on the finished chromatogram provides positive qualitative identification and accurate quantitative determination. Good recoveries were obtained in micro-concentration ranges.

Quantitative Determination of Vanillin and Ethyl Vanillin in Flavors by Paper Chromatography

1964 ◽  
Vol 47 (6) ◽  
pp. 1161-1165
Author(s):  
J Fitelson
Keyword(s):  
Quantitative Determination ◽  
Paper Chromatography ◽  
Alkaline Solution ◽  
Chromatographic Separation ◽  
Chromatographic Method ◽  
Ultraviolet Absorption ◽  
Photometric Method ◽  
Absorption Method ◽  
Ethyl Vanillin

Abstract Previous methods for estimating vanillin and ethyl vanillin in mixtures were long and complicated. However, this paper presents a simple chromatographic separation and quantitative determination of these aromatics, using Mitchell equipment for paper chromatography and 8 × 8” papers. Development for 2 hours separates the compounds adequately; they are then extracted and measured by absorbances at 348 mμ in alkaline solution. Recoveries of added vanillin and ethyl vanillin to vanilla extract are excellent. Aside from normal manipulative errors, the only significant inaccuracy is caused by the small amount of natural p-hy-droxybenzaldehyde in vanilla (usually equivalent to about 5% of the vanillin content). The method does not separate p-hydroxybenzaldehyde and vanillin. Total errors in the method do not exceed 0.01%. Comparison of the method with the two AOAC methods for vanillin shows that the paper chromatographic method gives results close to those by the ultraviolet absorption method, in most cases, and significantly lower results than the photometric method, which is known to give erroneously high results.

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%.

Quantitative Untersuchungen über die Ommochromvorstufen in den Malpighischen Gefäßen verschiedener Drosophila-Mutanten

1968 ◽  
Vol 23 (4) ◽  
pp. 547-554 ◽  
Author(s):  
Dieter Eichelberg
Keyword(s):  
Sex Differences ◽  
Drosophila Melanogaster ◽  
Quantitative Determination ◽  
Paper Chromatography ◽  
Type A ◽  
Individual Development ◽  
Wild Type ◽  
Strong Reduction ◽  
The Individual

This paper concerns with the quantitative determination of ommochrome precursors in the Malpighian tubes of Drosophila melanogaster during the individual development. After separation by paper chromatography the amounts of tryptophane, kynurenine and 3-hydroxykynurenine have been estimated by a spectrophotometer. The concentrations of these three substances obtained from wild-type Malpighian tubes have been compared with the quantities of the mutants brown (bw) and red Malpighian tubes (red). During development there are significant variabilities in contents of tryptophane, kynurenine and 3-hydroxykynurenine in the Malpighian tubes. In the larval tubes large quantities of ommochrome precursors are accumulated. With the beginning of metamorphosis there is a distinct decrease in these substances. After hatching the amount increases steadily until reaching a constant level. In the Malpighian tubes there are also sex differences: in females the concentration of kynurenine and 3-hydroxykynurenine is higher than in males. The results obtained from the mutants brown and red Malpighian tubes are on principle the same as those obtained from wild-type. A strong reduction of kynurenine contents is found in the mutant red Malpighian tubes. Perhaps in this mutant the kynurenine-hydroxilase-activity is lower than in wild-type. The amounts of ommochrome precursors, accumulated in the larval Malpighian tubes, do not correspond in all cases to the contents of xanthommatine formed in the eyes of the adults.

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