Thin layer chromatography plate dispersion

Bismethylaminoanthraquinone (Disperse Blue 14) [2475-44-7] M 266.3, A,max 640 (594)nm. Purified by thin-layer chromatography on silica gel plates, using toluene/acetone (3.1) as eluent. The main band was scraped off and extracted with MeOH. The solvent was evapd and the dye was dried in a drying pistol [Land, McAlpine, Sinclair and Truscott J Chem Soc, Faraday Trans I 72 2091 7976]. 

Raman and IR spectroscopy may be used to analyse spots on thin layer chromatography (TLC) plates. Unlike other methods, such as mass spectrometry or NMR, the spectrum may be obtained in situ without the need of scraping the spot from the plate and extracting the substance from the sihca matrix. Dispersive Raman miaos-copy has been used to collect spectra from active dmg substance on a plate [18,88]. 

In GPC of polymers it is desirable to avoid specific interactions between polymer and substrate. In the past few years there has been a very rapid increase in the use of thin layer chromatography (t.l.c.) for polymer analysis. In this technique it is possible to separate polymers either by size differences as in GPC or by chemical differences, thus making it extremely useful for analysis of polymer mixtures and copolymers. Applications of t.l.c. have been thoroughly reviewed. - Kamide et al. report studies of cellulose nitrate showing that the polymer can be dispersed on a t.l.c. plate according to either molar mass or nitrogen content. 

For the polymerization studies, multilamellar vesicular dispersions were prepared by vortexing the hydrated lipid dispersions. These dispersions were gel filtered on a Sephadex G 50-150 column and were polymerized at 5 C by 254 nm irradiation in a Rayonette Photoreactor. The course of the polymerization was monitored by thin layer chromatography on silica gel using a chloroformrmethanol water (65 25 4) solvent system. The monomer participation was measured in polymerized and freeze dried samples by dissolving the monomers in chloroform and spotting on the TLC plate, developing in lipid solvent and measuring the phosphorus content under monomer and polymer spots. 

With this method of chromatography the actual process takes place on a thin layer of adsorbent fixed on a glass or aluminum plate, or on a plastic foil. The separation takes place on the basis of a partition mechanism, adsorption, or ion exchange, etc. Individual mechanisms are often combined or overlap, and it is not easy to determine the boundaries between individual processes. Basic forces playing a decisive role during the separation are ionic forces, further coordination forces, chelate formation, association of dipoles, hydrogen-bond formation, and dispersion (van der Waals forces). 

---