Thin-Layer Chromatograms. H. Ganshirt

All experimental conditions must be accurately noted in the documentation of thin-layer chromatograms. A printed form like in Fig. 70 should be used to facilitate precise repetition in the future [214, 344]. 

With especially important chromatograms, a purely numerical documentation does not suffice for comparing, if necessary, all details like spot shape, spot area, resolution, course of the solvent front, subsidiary spots etc. A number of possibilities has accordingly been described for preparing the chromatogram so that it can be kept or that copies as faithful as possible can be made. 

In this method, the chromatograms, after appropriate previous treatment, are peeled off the glass plate as films and stored. This preservation of adsorbent layers has so far been used for documentation mainly with silica gel and alumina layers. 

Amino acid chromatograms have been preserved by impregnation with collodion to which a definite amount of glycerol had been added [42, 66]. Chromatograms have also been pasted over with self-adhesive plastic film and the layer subsequently peeled off the plate [354]. Spraying with polymer dispersions (polyacrylates, polyvinylidene chloride or polyvinyl propionate) is usually more suitable [402]. Such aerosols are commercially available (Firms 88, 153). Mention may be made also of impregnation of layers by immersion in solutions of polymers although this has a restricted application (Firm 60). 

After spraying new Neatan, the jets of the sprayer are cleaned with dimethyl-formamide to prevent blockage. 

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