Sugars, determination

In the particular example shown, zinc sulfate and barium hydroxide are being dispensed into the test tube so as to precipitate the proteins. The filtrate obtained is the filtrate from 10 microliters of serum. This can be used for several purposes and in the application being referred to, an amount equivalent to 3 microliters is being used for sugar determination, by the hexokinase procedure and an amount equivalent to 3 microliters is being used for urea estimation with diacetylmonoxime (15). 

Hydrolysis of xylan produces principally D-xylose.71 By hydrolysis of straw xylan in 3% nitric acid, Heuser and Jayme72 obtained crystalline D-xylose in 85% yield. Using a similar procedure, Hampton, Haworth and Hirst70 obtained a yield of 93% crystalline D-xylose from esparto xylan. A practically identical yield was indicated by reducing sugar determination made on the hydrolysis products of corn seedling xylan.68... 

The Sugar Determination.—Dilute the 5 c.c. sample in a measuring flask to 25 c.c. and pour 10 c.c. of this diluted solution into 25 c.c. of 01 N-iodine solution. Then add 40 c.c. of 0-1 N-sodium hydroxide solution (free from alcohol) and leave for twenty minutes. Make faintly acid with dilute sulphuric acid and titrate back with 0-1 N-sodium thiosulphate solution. One equivalent of iodine corresponds to 0-5 mole of reducing biose, or 1 c.c. of 0-1 N-iodine solution to 17-1 mg. of maltose. What is the course of the reaction ... 

Straight line plots are obtained by this method furthermore, the mutarotation coefficients for several sugars, determined under the same conditions as used in polarimetric work, give values identical to those obtained optically (see Table I). 

For any sugar determination, the specific quantification method chosen should selectively distinguish the different carbohydrates present in a same mixture. 

Somogyi, M. 1926. Notes on sugars determination. J. Biol. Chem. 70 599-613. 

CD. see Circular dichroism Cell wall polysaccharides isolation of plant cell walls and fractionation, 697-718 neutral sugars, determination by GC of alditol acetates, 721 -732 pectin... 

Gas-liquid chromatography (GLC) alditol acetates, neutral sugar determination, 721 -732 cholesterol measurement, 453-456, 460-462 (tables)... 

J Diaz, JL Lliberia, L Cornelias, F Broto-Puig. Amino acid and amino sugar determination by derivatization with 6-aminoquinolyl-V-hydroxysuccinimidyl carbamate followed by high-performance liquid chromatography and fluorescence detection. J Chromatogr A 719 171-179, 1996. 

With products prepared with addition of sugar, determinations of the saccharose and other sugars, i.e. of the lactose and of the invert sugar which may be formed by the inversion of the saccharose, are carried out by the following methods. 

Thanks are due to J. Puls, M. Sinner, and P. Hoffmann for the chromatographic sugar determinations, to H. H. Dietrichs for stimulating discussions, and to U. Schiitzmann for able technical assistance. 

Fig. 2. Reducing sugars ( ) determined by DNS method and OD (A) vs time for aerobic batch cultivation of T. reesei Rut-C30. The initial growth medium was a Mandels medium with 10 g/L of glucose as the carbon source. At t = 67 h, Solka Floe was added to a concentration of 10 g/L. (There were no measurements of OD after the addition of cellulose.)...

Wine making involves a series of very complex reactions most of which are performed by microorganisms. The starting concentration of sugars determines the final alcohol content and sweetness of the wine. The specific gravity of the starting stock is therefore adjusted to achieve desired quality of wine. 

Tests currently available to identify and quantify microbial damage are reviewed by Allen et al. [484]. These tests include GUAM fluidity tests, pH determinations, reducing sugar determinations, microscopic techniques, and staining methods. 

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