Saccharide analysis

Saccharide Analysis. The analysis of low DE starch hydrolyzates for their degree of polymerization (DP) saccharide profile was completed by a high performance liquid chromatographic method (W. 

Spectral Region 700-950 cm. The band at 895 cm" is discernible in wood and MP-6 (SCE temperature 250°C) but disappears from spectra of samples treated at higher temperatures where saccharides analysis has also shown the absence of cellulose. As carbonization proceeds, the out-of-plane bending below 900 cm" (at 870-881, 800-833 and 752-766 cm ) increases in intensity the position for some of the bands ( 800 and 750 cm ) can suggest condensed ring systems. 

Figure 4.21 shows the setup of a microdevice for saccharide analysis. The device is equipped with a sampling point that is coupled to a detection unit such as LC-MS, MS/MS, or ESI-TOF [61]. 

Analysis and Specifications. Typical product analyses include sohds level, ash, color, conductivity, purity, and minor saccharide levels (19). Specifications for anhydrous and monohydrate crystalline dextrose are available (15). High quahty anhydrous dextrose produced for the pharmaceutical industry is prepared in accordance with additional specifications (20). 

The separation was carried out on a TSKgel Amide-80 column 4.6 mm i.d. and 25 cm long with a mobile phase consisting of a 80% acetonitrile 20% water mixture. The flow rate was 1 ml/min and the column was operated at an elevated temperature of 80°C. The saccharides shown were 1/ rhamnose, 2/ fucose, 3/ xylose, 4/ fructose, 5/ mannose, 6/ glucose, 7/ sucrose and 8/ maltose. The analysis was completed in less than 20 minutes. These types of separations including other biomonomers, dimers and polymers are frequently carried out employing refractive index detection. 

Ion chromatography can be used in unique ways and by appropriate modification can often be applied to the separation of mixtures where the components themselves do not ionize or do not normally produce interactive ions in aqueous solution. A good example of this type of separation is afforded by the analysis of saccharide mixtures using ion exchange interactions. An illustration of such a separation is given in figure 15. 

Fig. 43. Compounds 167-171 form a series of diboronic acids for the complexation of saccharides with functional groups that permit analysis by circular dichroism measurements...

In the author s laboratory, it has never been found necessary to resort to matrices other than glycerol or 1-thioglycerol for the analysis of saccharides and glycoconjugates. Nevertheless, alternative matrices are often equally effective, and, in some laboratories, they are preferred. The most widely used include tetraethyleneglycol (4) and its higher-molecular-weight relatives, the poly(ethyleneglycol)s, and such basic matrices as N,N -bis(2-aminoethyl)ethylenediamine ( triethylenetetramine, 5), 2,2 -... 

Ion chromatography has become available and is used for sugar analysis. In this system a high-performance anion exchange column is used at high pH. This separation works because neutral saccharides behave as weak acids. Table 1 shows some pKa values. 

The D-galactosyl residues are the same as in disaccharide 33, and the fact that ribitol is substituted at 0-2 was evident from the methyl-ation analysis. Finally, a nonreducing tetrasaccharide was obtained, containing D-galactose, 2-acetamido-2-deoxy-D-galactose, and ribitol residues in the proportions 2 1 1. From these results, and periodate-oxidation studies, structure 36 was proposed for the neutral hexa-saccharide. 

Meyer, J. E. W. and Schulz, G. E. (1997). Energy profile of maltooligosaccharide permeation through maltoporin as derived from the structure and from statistical analysis of saccharide-protein interactions, Protein Set, 6, 1084—1091. 

The conformational behaviour in solution of a dermatan-derived tetra-saccharide has been explored by means of NMR spectroscopy, especially by NOE-based conformational analysis. RDCs were also measured for the tetrasaccharide in a phage solution and interpreted in combination with restrained MD simulations. The RDC-derived data substantially confirmed the validity of the conformer distribution resulting from the NOE-derived simulations, but allowed an improved definition of the conformational behaviour of the oligosaccharides in solution, which show a moderate flexibility at the central glycosidic linkage. Differences in the shapes of the different species with the IdoA in skew and in chair conformations and in the distribution of the sulphate groups were also highlighted.28... 

Combining 2D-NOESY and 2D-ROESY NMR experiments with molecular modelling protocols, Kuhn and Kunz32 have been able to study the saccharide-induced peptide conformational behaviour of the recognition region of Ll-Cadherin. The detailed conformational analysis of this key biomolecule not only proves that the saccharide side chain exerts a marked influence on the conformation of the peptide chain, but also that the size and type of the saccharide indeed strongly affects the conformation of the main chain. 

One special feature in the interpretation of the quantitative results seems not to have been exploited in practical analysis, and it certainly deserves attention. The result of the methylation analysis is sometimes complex, and can reveal the occurrence of 10 to 20 different methylated sugars. In this situation, it is not easy to decide, by simple inspection of the analytical data, whether the result could be caused by one complex, carbohydrate chain, or by a structure containing several saccharide chains bound to a common aglycon. In addition, it is not always easy to decide whether the result could fit any natural structure, or mixture of structures, or whether the complex result is attributable to undermethylation. 

---