title: Hydrolysis of bacterial wall carbohydrates in the microwave using trifluoroacetic acid.
abstract: By and large, monosaccharide composition and linkage analyses of bacterial cell-surface carbohydrates are achieved by hydrolysis into the corresponding monomeric constituents, and characterization of these, or their derivatives, by chromatographic and spectrometric methods. Normally, these hydrolyses are carried out conveniently with trifluoroacetic acid (TFA) at high temperatures for long periods of time, for example, in 4M TFA at 100 degrees C for 5h in a heating block. In this study, using a closed-vessel system, we investigated the effectiveness and reliability of microwave-assisted TFA hydrolysis of bacterial lipopolysaccharides, capsule, and teichoic-acid polysaccharides that were variably composed of several glycoses. In all cases, we were able to establish that 5 min of hydrolysis in the microwave at 120 degrees C with 4M TFA (measured pressure of 90 psi) was sufficient time to obtain comparable results to those afforded by conventional hydrolysis. The same observation was made when fully methylated carbohydrates were hydrolyzed. The data obtained with our microwave system (Aurora Instruments MW600) showed that microwave-induced hydrolysis can be used with a high degree of confidence to carry out sugar composition analysis of complex bacterial glycans in markedly shorter periods of time. The results also suggested that non-thermal mechanistic factors must also be involved, at least in part, in accelerating the reaction rate of glycosidic hydrolysis.
authors.affiliation: Department of Chemistry, University of Guelph, Guelph, ON, Canada N1G 2W1.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Zhao
authors.forename: Mario A
authors.initials: MA
authors.lastname: Monteiro
mesh_terms: D050260:Carbohydrate Metabolism / Q000187:drug effects / Q000528:radiation effects*; D002240:Carbohydrate Sequence; D002473:Cell Wall / Q000737:chemistry*; D002849:Chromatography, Gas; D006090:Gram-Negative Bacteria / Q000737:chemistry*; D006358:Hot Temperature; D006868:Hydrolysis / Q000187:drug effects / Q000528:radiation effects; D008872:Microwaves; D008969:Molecular Sequence Data; D013997:Time Factors; D014269:Trifluoroacetic Acid / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D014269:Trifluoroacetic Acid