Alditols quantitative determination

The quantitative determination of uronic acids in polysaccharides is complicated by lactonization, and these problems have been carefully examined by Blake and Richards.26,98 In the course of these studies, D-glucuronic acid was reduced to D-glucitol, which was characterized as the hexaacetate.98 As uronic acid residues in a polysaccharide may be reduced relatively easily,465,466 determination as the alditol provides an alternative method of analysis.461,468 This procedure is most valuable when different uronic acids are present in... 

Funakoshi, I., Yamashina, I. (1980). Quantitative determination of partially methylated alditol acetate of amino sugar by gas chromatography-mass spectrometry. Analytical Biochemistry, 107, 265 270. 

The constituent sugars of methylated cherry gum have been identified and quantitatively determined by g.l.c.-m.s. of the methylated alditol acetates formed from the methylated gum, the carboxy-reduced, methylated gum, and the carboxy-reduced, methylated gum after remethylation. The results of this and previous studies can be assessed in terms of three regions in the structure of cherry gum the outer residues of L-arabinose (12), branched-chains of D-galactopyranosyl residues mutually joined by (1 -> 3)- and (1 6)-linkages and bearing D-glucuronic acid residues (13), and residues of the aldobiouronic acid, 2-0-(jS-D-glucopyranosyluronic acid)-D-mannopyranose (14). 

Polysaccharides which contain uronosyl residues, such as the acidic pectic polysaccharides and the glucuronoarabinoxylans, pose a particular problem in quantitative determinations of glycosyl compositions. Urono-sidic bonds are resistant to acid hydrolysis. Conditions sufficiently harsh to hydrolyze the uronosidic bonds often result in significant degradation of the uronic acids as well as degradation of some of the neutral sugars. Uronic acids, even when converted into their monomeric form, do not form stable alditol acetates as the reduced form of an uronic acid is an aldonic acid which cannot be acetylated by the standard procedures. 

Sawardekar, J. S., Slonekar, J. M. Jeanes, A. (1965). Quantitative determination of monosaccharides as their alditol acetates by gas liquid chromatography. Analytical Chemistry, 37,1602-1604. 

Diols and polyols can participate in equilibria with boric acid in aqueous solution. The stability of polyolborates is determined by the number of OH groups in cis positions. Complexes with polyols are more stable than with diols, and 1,2-diol complexes are more stable than their 1,3-diol counterparts (Table 10) since the resulting five-membered chelate ring is unstrained.75120 In the case of 1,3,5-triols stable cage-like structures (5) and (6) are favored. Open-chain or five-membered cyclic polyols form more stable chelate complexes than their six-membered counterparts.120 Thus, chelates from alditols and ketohexoses are more stable than the corresponding aldose chelates (Table 10). Many polyols allow quantitative titrimetric determination of boric acid. Of these, mannitol remains the most widely used reagent on the basis of availability, cost and ease of handling.75... 

Methylation analysis. Peptidophosphogalactomannan and its degradation products were quantitatively methylated and the methylated polymers were converted to their permethylated alditol acetates in an attempt to determine the types of linkages in the polymer. The permethylated alditol acetates were separated and quantified by gas-liquid chromatography and they were identified by their fragmentation patterns in a mass spectrometer. 

The distribution of substituents in ethylcellulose has been determined by hydrolysis and conversion to the alditol acetates which were determined quantitatively by g.l.c. ° Reference ethyl ethers of D-glucose were synthesized and isolated from a hydrolysate of ethylcellulose of high degree of substitution, and the conformation of these derivatives determined by mass spectrometry. The ratio of ethylation on 0-2,0-3, and 0-6 was found to be 7.45 1 1.5. 

Monosaccharides can be identified by Curie-point pyrolysis (358°) and g.c. analysis (packed column) of the volatile products since fragments characteristic of the sugar class (e hexose, pentose, deoxy-sugar, uronic acid, alditol and amino-sugar) were obtained. Sugars and polyols in biological fluids have been determined quantitatively by g.c. of their pertrimethylsilyl ether derivatives. ... 

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