Silver Nitrate-impregnated Silica Gel Layers

Once the alcohols have been subdivided into groups containing the same number of C atoms, they can be further separated on the basis of the number of C=C bonds each contains. Using gradient-TLC, Stahl and Vollmann [267] have been able to show that 2.5% was the optimum and most economical content of silver nitrate in the layer (Fig. 105a). A mixture of methylene dichloride-chloroform-ethyl acetate- 

Pesnelle et al. [195] have used 10% silver nitrate-silica gel G layers and cyclohexane-ethyl acetate (60 + 40) in order to separate galbanol [327], formerly believed to be a single compound, into bulnesol, guaiol and jS-eudesmol. 

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Lawrence, B.M. The use of silver nitrate impregnated silica gel layers in the separation of monoterpene hydrocarbons. J. Chromatogr. 1968, 38, 535-537. 

Several authors have reported the analysis and purification by TLC, of substances which had been tritiated according to the Wilzbach procedure. Thus glycerol ethers [262], the insect hormone ecdysone [338], vitamin Dg [501] and other steroids [501, 513, 617] (see Fig. 93, p. 170) and cardiac glycosides [551] have been purified on silica gel G layers. Unsaturated fatty acids have been isolated by TLC on silver nitrate-impregnated silica gel layers [425, 628]. 

Solanidine and demissidine can be separated on a silver nitrate-impregnated silica gel layer. Schbeibeb et al. [207 b] have used TLC also for preparative separation of Solanum alkaloids. Using 8 solvents on silica gel G layers, Paqijin and Lepage [158] have separated the three principal alkaloids from Solanum tuberosum, i. e., solanine, chaconine and solanidine. Antimony(III) chloride reagent was used for visualisation. P bez-Medina et al. [164] have investigated many Solanum species in the search for a raw material source of solasodine. They used TLC on silica gel 6 with n-butanol-methanol-diethylamine (85 + 5 + 10) as solvent and antimony(III) chloride (Rgt. No. 16) for visualisation. The TLC of this alkaloid class is described in other publications [2, 25, 183, 208]. 

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