Shirley C. Churms

• PhD
• Consultant at University of Cape Town

This chapter discusses the application of high-performance liquid chromatography (HPLC) to the chromatographic analysis of carbohydrates. The major area of growth has been in the use of high-pH or high-performance anion-exchange chromatography (HPAEC), which is a form of ion chromatography developed specifically for the analysis of sugars. Mass spe...

This chapter discusses size-exclusion chromatography (SEC) of carbohydrates and glycoconjugates. SEC is an unparalleled technique for the fractionation of carbohydrates of high molecular weight, both polysaccharides and glycoconjugates. It is based upon the decreasing permeability of a stationary phase consisting of a porous, three-dimensional netw...

Since the introduction of stationary phases based on microparticulate porous silica and polymeric sorbents, rigid and semi-rigid, size-exclusion chromatography (SEC) has become established as a form of high-performance liquid chromatography. In recent years, there have beeen revolutionary developments in detection systems for high-performance SEC,...

This article surveys recent developments in the separation and analysis of carbohydrates by high-performance liquid chromatography, in adsorption or partition modes, on polar sorbents with less polar eluents, a technique that is now termed hydrophilic interaction chromatography. A variety of chromatographic methods are included under this generic h...

This chapter describes the high-performance hydrophilic interaction chromatography (HIC) of carbohydrates with polar sorbents. The intermolecular forces governing selectivity in this case are polar in origin, encompassing hydrogen bonding, which depends upon the acidity or basicity (in the Lewis sense) of the interacting molecules, and a dipole–dip...

Partial acid-hydrolysis of the gum exudates from Hakea sericea and H. gibbosa yields L-arabinose, D-galactose, D-xylose, D-mannose, D-glucuronic acid, the aldobiouronic acid GlcA (beta 1,2)Man, and a dimer of this acid alpha-linked from D-Man to O-4 of GlcA. Methylation analysis showed the modes of linkage of the sugar units to be typical of those...

This sixth volume in the Gums and Stabilisers series is based on the 6th Wrexham Conference which took place in July 1991. As such it reflects the new trends and concerns which are associated with the industry, placing major emphasis on the practical aspects of the subject, and integrating the knowledge of the academic researcher with the experienc...

Commercial black wattle extract, from which most of the tannin had been removed with organic solvents (so being enriched with “non-tannins”) and low-molecular-weight constituents by dialysis, was fractionated by chromatography on polyvinylpolypyrrolidone (PVPP). Steric-exclusion chromatography (SEC) then yielded a polysaccharide—protein conjugate,...

The impact on carbohydrate chemistry and biochemistry of the many significant developments in chromatographic analysis during the past decade is discussed and assessed. New techniques, such as supercritical fluid chromatography and ion chromatography with pulsed amperometric detection, have been applied with advantage, and the use of highly efficie...

Partial acid hydrolysis of Grevillea robusta gum, which removed most of the l-arabinose residues (∼44% of teh total carbohydrate), yielded a polysaccharide (A) containing galactose, arabinose, mannose, and uronic acid in the molar ratios 3:1:1:2. Smith degradation of A gave SDA, w 4400, which contained galactose and mannose residues in the ratio ∼1...

The extracellular arabinogalactan-protein from suspension-cultured cells of Lolium multiflorum (ryegrass) was purified in a single step by affinity chromatography of the culture medium on myeloma protein J539-Sepharose. The product obtained after two Smith-degradations had an apparent molecular size corresponding to that of galactoheptaose and was...

Analysis of the arabinogalactan-protein isolated from a specimen of Acacia hebeclada gum has shown major differences in composition between this and a specimen previously examined in another laboratory. In its much lower proportions of protein and uronic acid, and higher arabinose content, the present specimen of A. hebeclada gum resembles more clo...

The gum exudate from Acacia erioloba (syn. giraffae) contains protein (53–56%) and carbohydrate as a mixture of glycoproteins that are relatively resistant to proteases and not readily separable. The protein components have high contents of hydroxyproline and serine, and the carbohydrate is composed mainly of l-arabinose, d-galactose, and 4-O-methy...

The gum exudate from Acacia tortilis. its Smith-degradation products, and the partially hydrolysed gum are associated with protein. The presence of periodate-immune arabinosyl chains which protect otherwise vulnerable galactosyl residues is the cause of only limited breakdown of the gum during Smith degradation. Removal of the arabinosyl groups fol...

The gum exudate from Acacia robusta (subspecies clavigera) has been found to contain protein (18% w/w), bound to an arabinogalactan having structural features typical of the gum polysaccharides from Acacias of Bentham's Series 4 (Gummiferae), of which A. robusta is a member. Three sequential Smith degradations yielded an oligosaccharide of molecula...

This chapter introduces the use of the newer techniques in the isolation and analysis of carbohydrates and their derivatives, but, within this context, some of the longer-established methods—such as ion-exchange and gel-permeation chromatography—remain relevant, particularly in view of their compatibility with the various automated detection system...

The gum polysaccharide of Acacia senegal, the main source of gum arabic, has been re-examined by means of two series of sequential Smith degradations, one starting with the whole polysaccharide, the other with a product from which all acid-labile side-chains had been removed by prior partial hydrolysis. Investigation, mainly by methylation analysis...

The gum polysaccharides from two species of Prosopis, namely, P. glandulosa and P. chilensis, growing in different locations in South Africa, have been found to have similar structural features, closely resembling those reported in the literature for the gum of the North American species P.juliflora (mesquite). On smith degradation, both of the gum...

The capsular polysaccharide of Klebsiella serotype K27 had been investigated by techniques involving methylation analysis, autohydrolysis, and graded hydrolysis with acid. The anomeric configurations of the sugar constituents were determined, where possible, on the basis of p.m.r. spectroscopy and optical rotation data. The results of these studies...

Smith degradation of each of the polydisperse, gum polysaccharides from Acacia pycnantha, A. difformis, A. filicifolia, and A. podalyriaefolia, for which molecular-weight distributions have been measured by gel-permeation chromatography, gives, in good yield, a methanol-insoluble polysaccharide that shows a single peak on examination by this techni...

Study of the molecular-weight distribution of the raw gum exuded from Acacia baileyana F. Muell., of partially hydrolysed material, and of products of successive Smith-degradations of the gum suggests the occurrence of sub-units having a molecular weight of ∼4000. These sub-units consist of β-(1→3)-linked d-galacto-pyranose residues, to most of whi...

Methylation analysis of and partial hydrolysis studies on the Klebsiella K7 capsular polysaccharide and its carboxyl-reduced derivative indicated the recurrence of D-glucopyranuronic acid, D-mannopyranose, and D-glucopyranose residues, linearly linked in a specific manner, in the molecular structure. D-Galactopyranose and pyruvic acid residues are...

Gel-permeation chromatography has been used to determine the molecular-weight distribution of the products at various stages of acid hydrolysis of some capsular polysaccharides from klebsiella bacteria. Structurally significant oligosaccharides, which are believed to correspond closely to the chemical repeating units in the polysaccharide molecules...

The behavior of the polysaccharide gum of Acacia elata on acid hydrolysis has been studied by gel chromatography. The changes in the clution pattern and weight-average molecular weight as hydrolysis progresses resemble those found on hydrolysis of the structurally similar polysaccharide of A. Podalyriaefolia gum. The molecular weights corresponding...

The composition of the gum exuded by Cussonia spicata Thunb. has been examined by partial hydrolysis with acid, methylation analysis, and sequential Smith-degradation, with extensive use of gel chromatography in order to determine the molecular-weight distributions of the gum polysaccharide and its degradation products The evidence thus obtained su...

Gel chromatography is also commonly known as “gel filtration,” “gel-permeation,” or “molecular-sieve chromatography.” This technique is based on the decreasing permeability of the three-dimensional network of a swollen gel to molecules of increasing size. In specific, if a solution containing a mixture of solutes of different molecular sizes is pas...

The course of acid hydrolysis of the polysaccharide gum of Acacia podalyriaefolia has been followed by gel chromatography. Elution patterns of samples removed at intervals demonstrate the rapid hydrolysis of arabinofuranoside linkages and subsequent, preferential removal of galactopyranose end-groups. The persistence of certain peaks in the hydroly...

Partial acid hydrolysis of the gums from stems of Acacia podalyriaefolia and A. elata gives polymer mixtures, together with oligosaccharides and monosaccharides, which have been characterized by paper chromatography and by GLC of their derived glycitol acetates. The acid-degraded polymers have been shown by methylation, methanolysis and GLC assay t...