Argentation thin-layer chromatography

Argentation thin-layer chromatography is an extemely useful procedure for the separation of methyl esters of fatty acids. Saturated fatty acids have the highest Rf values, which decrease with the increasing degree of unsaturation, and for a particular acid, the trans isomer usually travels ahead of its corresponding cis isomer. The solvents most commonly used contain hexane and diethyl ether (9 1) although a mixture of 4 6 is used to separate compounds with more than two double bonds. In order to separate positional isomers of the same acid, conditions must be carefully controlled and multiple development in toluene at low temperatures is often necessary. 

Such AOAC method is a satisfactory method but is thought not to be in current use for various reasons thin-layer chromatography argentation thin-layer chromatography ultraviolet (detector)... 

We have recently been able to show (34) the presence of a minor component in extracts of many -cultivars of pepper grown in India and Ceylon by the reversed phase, argentation thin-layer chromatography of the isolated total pungent components. This component has the typical 360 nm maximum attributed to piperettine and has shown very little pungency. We are still working on further isolation and purification for study by mass and nuclear magnetic resonance spectroscopy. 

In argentation thin-layer chromatography, a major technique for lipid separations, application is made of the ability of silver to form complexes with lipids. Silver nitrate is incorporated in either the stationary or mobile phase, and separations are based on the type (such as cis-trans) and extent of unsaturation in the lipids. This type of chromatography has been reviewed by Morris. ... 

As emphasized, dietary fatty acids produced drastic modification of the molecular species of brain ethanolamine phospholipids. Hargreaves and Clandinin reported similar findings in the rat (Connor et al., 1997). Using argentation thin-layer chromatography (TLC), which is unable to resolve individual molecular species, they fed fish-oil or linseed-oil diets to rats, which resulted in an increased microsomal and synaptic membrane content of phosphatidylethanolamine species containing six double bonds, and a decrease in species containing five double bonds, compared with animals fed soy or safflower oil. 

Dimethylsterols (triterpene alcohols). The main triterpene alcohols present in olive oil are (3-amyrin, butyrospermol, cycloartenol and 24-methylene-cycloartanol (Figure 9.6). This sterol fraction is complex and many constituents are still unidentified. Itoh and his co-workers (1981) used argentation thin layer chromatography and GC-MS to identify minor 4,4-dimethylsterols present in olive oil and olive pomace oil ((3-residue oil). 

Martinez-Lorenzo, M. J., Marzo, I., Naval, J. et al. (1994) Self-staining of polyunsaturated fatty acids in argentation thin-layer chromatography. Analytical Biochemistry, 220 (1), 210-12. 

Morris, L. J. and Nichols, B. (1972) Argentation thin-layer chromatography of lipids, in Progress in Thin-layer Chromatography, Related Methods (ed. A. Niederwieser), Ann Arbor-Humphrey Science Publishers, Ann Arbor, MI, pp. 74-93. 

Pyka and Bober " separated a- and y-terpinene as well as a- and 3-pinene on silica gel and on silica gel impregnated with various percentages of silver nitrate. It was stated that argentation thin-layer chromatography is an efficient technique for separation of isomeric a- and y-terpinene as well as a- and (3-pinene. The topological indices based on... 

Fig. 3.1. Argentation thin-layer chromatography plate of a L-P-P/P-L-P regioiso-meric mixture obtained by interesterification (left lane) total milk fat triacylglycerols (TAG middle lane) and CLA-P-P obtained from the reaction of 1,2-dipalmitin with CLA (right lane). P, palmitic acid L, linoleic acid. CLA-containing TAG were found between bands two and three and in band six. (Published with permission from Ref. 28 and redrawn from original.)...

Morris L J, Warry P M, et Hammon W E, Chromatographic behaviour of isomeric log-chain aliphatic compounds.Argentation thin-layer chromatography of isomeric compounds. Chromatog 1967 31 69-76. 

Chloroplasts were incubated with [ " C]acetate to isolate MCTE activity from p-oxidation. Radiolabelled fatty acids were extracted and separated using successive argentation thin layer chromatography (TLC) and Cig-reverse phase TLC. The Brassica chloroplasts did not synthesise fatty acids well whereas control spinach chloroplasts incorporated [ " CJacetate into fatty acids at a rate of 100-300nmol/hour/mg chlorophyll, the Brassica chloroplasts had a specific activity of only approximately 20nmol/hour/mg chlorophyll. 

Figure 4.3 Analysis of acylglycerols by combination of argentation-thin layer chromatography and gas-liquid chromatography.

Prior to structural elucidation and possible eventual synthesis, the isolation of component phenolic lipids in a pure state is essential. The cold methods of thin layer chromatography (TLC), column chromatography (CC), flash chromatography, high performance liquid chromatography (HPLC) and hot methods (GC), often after derivatisation, are well established. Argentation versions of these separatory methods are less common but are desirable for the rapid separation of unsaturated constituents. 

Thin Layer Chromatography.- Argentation t.l.c. has been suggested as suitable for the separation of arachidonic acid from the major metabolites produced by blood plate lets. ... 

Kozutsumi, D. Kawashima, A. Adachi, M. Takami, M. Takemoto, N. Yonekubo, A. Determination of docosahex-aenoic acid in milk using affinity solid phase purification with argentous ions and modified thin layer chromatography. Inti. Dairy J. 2003,13 (12), 937-943. 

ARGENTATION TLC. Thin-layer chromatography using a layer, usually silica gel, impregnated with silver nitrate for the purpose of improving the separation of certain compounds. 

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