Plant waxes thin-layer chromatography

Chen, X., and B. R. T. Simoneit, Epicuticular Waxes from Vascular Plants and Particles in the Lower Troposphere Analysis of Lipid Classes by Iatroscan Thin-Layer Chromatography with Flame Ionization Detection, . /. Atmos. Chem., 18, 17-31 (1994). 

The fatty/waxy products contained the lipophilic substances, including fatty oils, waxes, resins and colorants. Valuable pharmacological effects were proved for some minor constituents of these products (e.g. triterpenes, diterpenes, sterols and carotenoids). Thin layer chromatography and on-line UV-VIS spectroscopy were used for the quick identification and quantity determination of these compounds using authentic samples as standards. The SFE method proved favorable in terras of both extraction yield and speed of carotenoids. The CO2 extracts of the lavandin, clary sage and thyme have been enriched in triterpenic compounds (a-es P-amyrin, oleanic acid, ursolic acid, etc.) and phytosterols. Both free and esterified triterpenoids were present in the extracts of the different samples. Furthermore camosol and other diterpenes were detected in the SFE extract of Lamiaceae plants. The fatty acid composition was only slightly different for extracts obtained by SFE and conventional hexane extraction. 

Thin-layer chromatography (tic) or column chromatography on silica gel is the most widely used technique for separating plant waxes into fractions of... 

In the examination of plant waxes various analytical methods have been used, including ultraviolet and infrared spectroscopy, and thin-layer, column, and gas-liquid chromatographies (Eglinton and Hamilton, 1967). The infrared spectrum has been used to indicate hydroxy compounds, ketones, ethers, and lactones, as well as the more common esters and hydrocarbons. In the use of thin-layer or column chromatography, infrared spectra can be used to make sure that there is no carryover of one class of components into another. 

Figure 6.12 Chromatography and mass spectrometry of plant waxes. (1) Thin-layer chromatogram of broccoli leaf wax and gas-liquid chromatogram of the hydrocarbon fraction isolated from this wax. (2) Partial gas-liquid chromatogram of the alkane fraction from the surface lipids of tobacco leaves. (3) Partial gas-liquid chromatograms of the hydrocarbons from N. muscorum illustrating resolution of 8- (a), 7- (b) and 6- (c) monomethyl heptadecanes on a 750ft capillary column. (A)-(C) Partial mass spectra taken at points indicated in (2) illustrating identification of n- and branched alkanes. Reproduced with permission from Kolattukudy (1980).

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