Polysaccharide analysis infrared spectroscopy

After their isolation by chromatographic techniques (anion-exchange chromatography, size exclusion, etc.), different analytical methodologies have been used to identify and quantify the polysaccharides in wine the most commonly used being the traditional methylation analysis followed by GC-MS (Doco and Bril-louet 1993). Polysaccharides have also been determined after solvolysis with anhydrous methanol containing HCl by GC-MS of their per-G-trimethylsilylated methyl glycosides (Vidal et al. 2003). Other techniques such as Fourier transform infrared spectroscopy (FTIR) have been more recently proposed (Coimbra et al. 2002,2005 Boulet et al. 2007). 

An investigation of polysaccharide sulfates has further demonstrated this particular application of infrared spectroscopy to the structural analysis of these compounds, but, at the same time, it serves to emphasize the need for the simultaneous observation of other properties. 

MA Coimbra, F Goncalves, AS Barros, I Delgadillo. Fourier transform infrared spectroscopy and chemometric analysis of white wine polysaccharide extracts. J Agric Food Chem 50 3405-3411, 2002. 

Infrared spectra of glycosaminoglycans in D20 and DC1 were used165 for quantitative evaluation of the uronic acid and acetamido groups in this class of polysaccharide. The results showed that i.r. spectroscopy of compounds in D20 solution provides a simple, quantitative basis for examination of ras(COJ) and amide I bands in heparin and chondroitin 4-sulfate. In DC1, analysis was based on p(C02H) and amide I bands which were well resolved. The apparent acid-dissociation constants of the studied polysaccharides were estimated from the absorbance of p(C02) or p(C02H) bands, or both, at different pH (pD) values. 

Techniques proved useful in graft-polymerization chemistry include the use of electron-spin resonance spectroscopy for the determination of the initiating radical in gamma-irradiation-induced copolymerization, and of thermogravimetric and infrared analysis for product characteriza-tion. The particular solvent employed for the polymerization may be important in its dispersion of the polysaccharide. ... 

Fourier transform infrared (FTIR) spectroscopy is an important analysis technique for determining the composition, chemical structure, and branching in some pol5miers. FTIR spectroscopy is used to investigate the molecular vibrations and polar bonds between different atoms. Structures of polysaccharides, such as monosaccharide types, glucosidic bonds, and functional groups, can be analyzed using FTIR spectroscopy. 

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