Auxins and Urine Metabolites

Some authors have used cellulose [103] or alumina layers [60] (Table 88, VII), partly in mixtures with silica gel [19], in order to separate basic and neutral substances. Indole derivatives on alumina- and especially on cellulose layers, generally tend to tail-formation. Benassi et al. [2] have accomplished good separations of urine metabolites on 100 (xm thick polyamide layers. The completely smooth layers prepared with polyamide powder DF (Firm 118), fluorescing in UV254, yield sharply defined zones they are, however, very sensitive to rubbing so that there are limits to midtiple application of an extract [46] (Table 88, XII). 

Solvents. The acid and ammoniacal solvents (Table 89, XIV and XVI), suggested by Stahl and Kaldewey [120], have been in the meantime (with some modifications — Table 89, XV and XVII) applied successfully to separation of auxins and urine metabolites. 

More strongly polar, acid solvents (Tables 88 and 89, VIII, IX, X, XVII [28]) have proved satisfactory for the mostly basic urine metabolites of serotonine and tryptophan these have been used partly in combination with basic systems and two-dimensional separation (Tables 88 and 89, XIV and XVI, XV and XVI, XIII and IX) or multiple development (Table 88, X and XI cf. here p. 481). 

The formic acid-containing solvents (Table 88/89, VIII and XVIII), so far not used for this purpose, should be suitable for separating urine metabohtes especially in multiple development. 

When using the mixtures mentioned, the compounds show essentially the same sequence after separation a more or less inverted separation pattern is shown in solvent XII, Table 88, on polyamide layers. 

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