Carbohydrates borate complexes

CZE separation of sugar isomers in a PMMA chip was enhanced by using a phosphate-based, rather than a borate-based buffer. The resolution enhancement may be caused by a rapid carbohydrate-phosphate complex formation process, as compared to a slow carbohydrate-borate complex formation process. To reduce adsorption of the labeled sugar isomers to the PMMA surface, 0.5% methylcel-lulose (viscosity of 2% aqueous solution at 20°C, 4000 cP) was added to the run buffer [560],... 

The borate buffer is the most effective buffer for the CZE separation of native (and derivatized) carbohydrates. Borate complexes with adjacent hydroxyl groups on carbohydrates to form a negatively charged complex, which has a 2- to 20-fold increased UV absorbance at 195 nm. ... 

Gorin, P.A.J. and Mazurek, M. "C Magnetic Resonance Spectroscopic Evidence for Formation of Borate Complexes of Polyhydroxy Compounds," Carbohydrate Research. 27(1973), 325-339. 

Bell, C.F., R.D. Beauchamp, and E.L. Short, Borate complexation withpentitols a study by nB-N.M.R. spectroscopy andMNDO semi-emperical LCAO-MO calculations. Carbohydrate Research, 1989.185 p. 39-50. 

Indirect conductimetry with a mobile phase containing polyol-borate complexes allows a detection limit of 10-5 mol of carbohydrate (53). A lower sensitivity is reached with the moving-... 

Modify mobility Borate Complex with carbohydrates, diols... 

Proteins, amino acids, and carbohydrates have all been. separated in minimum times by CZE. In the case of neutral carbohydrates, the separations are preceded by formation of negatively charged borate complexes. The separation of protein mixtures is illustrated by Figure 33-13. Feature 33-1 discusses the use of capillary electrophoresis arrays for DNA sequencing. 

The reversible formation of borate esters by carbohydrates in aqueous solution has been known for over a century, and played a role in early conformational studies.Currently it is an ancillary in the separation of carbohydrates, and with its aid very fine separations can be achieved - the secondary tritum isotope effects at H2, H3, H5 and H6 (but not HI) of glucose on borate complexation permit complete isotopic separation to be achieved by ion-exchange chromatography. ... 

Mazurek and Perlin have made a study of some borate complexes of carbohydrates having a m-l,2-diol system, and their results indicate the promise of this particular field of study. 

M. Igawa, T. Sekimoto and H. Okochi, Facilitated transport of carbohydrates via complexation with borate ion fixed on an anion exchange membrane, J. Membr Sci.,... 

Sinner, M., Simatupang, M.H. and Dietrichs, H.H., 1975. Automated quantitative analysis of wood carbohydrates by borate complex ion exchange chromatography. Wood Sci. Technol., 9 307—322. 

Fig. 4.6. Anion-exchange chromatography of carbohydrates as their borate complexes. Chromatographic conditions column, Aminex A-28 10 /im (50x0.3 cm I.D.) mobile phase, gradient of 40 ml of 0.124 M borate, pH 7.0 to 40 ml of 0.58 M borate, pH 10.0 flow rate, 10 ml/h temperature, 55°C detection, orcinol reagent reacted at 100°C for 20 min and measured by UV at 420 nm. Reproduced from Morrison et al. (1976), with...

Profound changes in the spectra upon formation of the boric complex as well as strong similarities, both between the free carbohydrates and their complexes, can be observed. There was only one type of anomeric proton for the complexes, suggesting either one exclusive molecular structure in the complex or an extremely fast exchange among two or more conformations. The spectra of the borate complexes were exactly reproducible even after several weeks, thus apparently indicated no slow equilibration or decomposition. It is beheved that the changes in the... 

The hydrolysate (monosaccharide mixture) is analyzed by chromatographic methods. The ion exchange chromatography of the borate complexes of neutral monosaccharides is the most common method, which is used as the basis of fully automatic carbohydrate analysis. 

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