Aldonic acids chromatography

Smith and coworkers152 published a relatively complete paper on the thin-layer chromatography, on silica gel, of carbohydrates of low molecular weight. Bancher and coworkers153 reported the thin-layer chromatography of degradation products of carbohydrates, including aldonic acids and aldonolactones. 

Aldonic acids and glucuronic acids have been separated by use of anion-exchange chromatography on Dowex-1 X-8, a strongly basic resin.164-166... 

The relationship between structure and paper-chromatographic mobility of aldono-1,4-lactones has been discussed.65 Butanone, saturated with water, is suitable for the preparative separation of lactones on cellulose columns free acids and reducing sugars move very slowly in this system. Separation of aldono-1,4-lactones and of aldonic acids as their O-(trimethylsilyl) derivatives has been accomplished.66 The mass spectra of such derivatives are characteristic, so that it is possible to identify aldonic acids67 and lactones68 by means of combined gas chromatography-mass spectrometry. 

This method involves the oxidation of aldoses to aldonic acids by potassium hypoiodite in methanol and the condensation of the isolated potassium salt of the aldonic acid in hot acid with o-phenylenediamine (M3). The specific aldobenzimidazole can be identified by the solubility in water, optical rotation in acid, and melting point. This method is not as simple as chromatography. It requires dehydration of the sample and a relatively high concentration of the sugars to be identified. 

Thin-layer chromatography of a number of aldonic acids, their lactones and phenylhydrazides on silica gel G with XXI has been reported (Table 204) [16]. The mobilities of the y-lactones have been reported also in the neutral solvent XXII (Table 204) [47]. While the y- and d-lactones and the free acids are well differentiated, the differences in hi /-values between the free acids are slight [16]. 

Pollock and Jermany (1968), using the asymmetric alcohols, butan-2-ol, 3-methylbutan-2-ol and 3,3-dimethyl butan-2-ol as the esterification reagents for each of a number of acids including lactic, glyceric, malic, mandelic and tartaric acids, demonstrated the separation of the resulting diastereoisomers after acetylation on a Carbowax 20M column. Their study, however, was directed principally at resolving various racemic carbohydrate diastereoisomers by conversion to aldonic acids prior to derivatization and gas chromatography. 

In the carbohydrate series, the acids encountered are aldonic, aldaric, uronic, or saccharinic acids. Often, these acids are readily transformed into their lactones or methyl esters, and it is as derivatives of these that they are commonly studied. Table VIII (see p. 136) records examples in which derivatives of such acids and lactones have been subjected to gas-liquid chromatography. 

Aldonic, uronic, and ascorbic acids, lactones, and N-acetylated amino sugars were separated on sulfonated polystyrene-divinylbenzene, a strong polyanion exchanger (Wheaton and Bauman, 1953). This method is adaptable to neutral carbohydrates without complexation or adsorption, by immersion in strong alkali to ionize the hydroxyl groups (ion chromatography). 

The hydrolysis of o-galactono-l,4-lactone has been examined using pH, optical rotation, and conductance methods, and the abilities of a series of aldonic, alduronic, and aldaric acids to form complexes with Fe +, Fe +, Mn +, Cu +, Al +, Ni +, and Co + ions have been investigated using paper chromatography. Bivalent metal ions have been shown to influence the proportions of n-ribo and D-ora6//70-cyanohydrins obtained when D-erythrose reacts with sodium cyanide. ... 

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