Uronic acids analytical

Blumenkrantz, N., Asboe-Hansen, G. (1973). New method for quantitative determination of uronic acids. Analytical Biochemistry, 54,484—489. 

Blumenkrantz, N., and G. Asboe-Hansen New Method for Quantitative Determination of Uronic Acids. Analyt. Biochem. 54, 484 (1973). 

Uronic acid content was determined as anhydro-uronic acid (AUA) by the automated colorimetric /n-hydroxydiphenyl assay [2,3,6] using an auto-analyser (Skalar Analytical BV, Breda, The Netherlands). Corrections were made for interference by neutral sugars present in the sample. 

Traces of the complex carbohydrates contained in the juice survive the processing and appear in the molasses analytical data indicate that they probably consist largely of pectins and pentosans.10 Quantitative estimations based on the ash-free solids of Louisiana molasses revealed the presence of 2% uronic acids and 0.5% methoxyl.16 Heat-modified... 

One of the most important reactions of hexuronic acids and glycuronans is the decarboxylation caused by treating with strong acids (usually 12% hydrochloric acid). The rapid and stoichiometric loss of 1 mol of carbon dioxide per mole has been developed as an analytical method by many workers.227 Methods based on the formation of colored phenolic compounds in strongly acidic media are widely used to assay total uronic acid.228,229 The method of Blumenkrantz and Asboe-Hausen228 has been adapted for microtiter plates.230... 

Despite indications (from analytical data) that a monomethyl ether of a uronic acid occurs in the hydrolyzates of several polysaccharides, definite evidence for the presence of 4-O-methyl-D-glucuronic acid did not appear until 1948, when White found it in mesquite-gum hydroly-zate.14 Confirmation of its presence therein has since13 appeared, and it has also been found in the hydrolyzates from gum myrrh,6 aspen wood,14 and Eucalyptus regnans wood.16... 

Mopper, K. (1977) Sugars and uronic acids in sediment and water from the Black Sea and North Sea with emphasis on analytical techniques. Mar. Chem. 5, 585-603. 

A (D-glucosylamine)uronic acid derivative has been identified331 as the metabolite of carbamazepine (5//-dibenz[fe,/]azepine-5-carbox-amide, an anti-epileptic agent) by means of permethylation, g.l.c., and mass spectometry. Analytical data for the conjugate (identified in the bile of the isolated, perfused, rat liver) indicated that the carboxamide nitrogen atom is linked to C-l of the sugar moiety. 

The analytical determinations most often made on a polyuronide before it is hydrolyzed are those for uronic acid, pentosan, methyl-pentosan, methoxyl and ash. The percentage of hexosan is usually estimated by difference. When the polyuronide has been obtained as a free acid it can in many cases be titrated with a base. Such metals as sodium, potassium, magnesium, calcium and iron often occur and especially so in plant gums and mucilages. 

Uronic acids are important components in many naturally occurring polysaccharides. By chemical or enz)matic degradation of these polysaccharides, smaller uronic acid units ranging from monosaccharides to smaller oligosaccharides can be prepared. In this connection, reduction of the carboxyl group can serve both synthetic and analytical purposes. 

Analysis of carbohydrates in delignified wood and pulp involved enzymic hydrolysis (cellulase, hemicellulase), derivatization of the free sugars with ethyl p-aminobenzoate and capillary zone electrophoresis. All reducing sugars, i.e. neutral monosaccharides as well as uronic acids, were quantified in a single analytical run, and 4-deoxy-P-L-r/ireo-hex-4-enopyranosyluronic acid present in the pulps was also detected. ... 

The phenol-sulfuric acid method involves treatment of the solution containing the carbohydrate analyte (5—40pgml ) with an aqueous solution of phenol (5%, m/v) and then concentrated sulfuric acid a characteristic yellow color is produced, with an absorption maximum at 490 nm for hexoses, 480 mn for pentoses, deoxy sugars, and uronic acids. Only amino sugars do not react. Oligo- and polysaccharides are hydrolyzed to their constituent monosaccharides by the addition of concentrated... 

A number of cyclic polyols also are known to occur (Fig. 15.13). myo-Inositol (62), widespread in animals, is a growth factor in yeasts and a group B vitamin. This compound, one of nine possible stereoisomers, is widespread in plants (six other isomers also are naturally occurring). When plant cells are incubated with radiolabeled myo-inositol, a large portion of the label appears in the pentose and uronic acid residues of the cell wall (Karr, 1976 Loewus and Loewus, 1980). myo-Inositol serves as a precursor for o-glucuronic acid (3). Furthermore, when glucose and other monosaccharides are incorporated into cell walls, myo-inositol appears to be an intermediate (Karr, 1976 Loewus and Loewus, 1980). Analytical techniques for the study of cyclitols and sugar alcohols (polyols) have been reviewed (Beck and Hopf, 1990 Loewus, 1990). 

---