Gas chromatographic studies of derivatives of celluline-like substances.
Abstract Different aspects of the gas chromatographic determination of the celluline-like substances exhibiting specific cardiotonic activity are discussed. As this substances is isolated from frog skin and bladder, many impurities have to be considered. Determination of these samples, having a broad range of boiling points, was performed by means of programmed-temperature gas chromatography. Identification of unknown peaks was executed with the help of pure standard substances and retention indices.
A GENERALIZATION OF THE RETENTION INDEX SYSTEM INCLUDING LINEAR TEMPERATURE PROGRAMMED GAS-LIQUID PARTITION CHROMATOGRAPHY.
Abstract The different ways of describing peak positions on gas chromatograms are reviewed. The retention index is preferred to the theoretical nonane system and the relative retention. The equation given by Kovats for the calculation of the retention index in case of isothermal operation is transformed to a more general form to include also the case of linear temperature programmed operation. This generalized equation gives the same retention index for both ways of operation.
Regeln zur Wahl der gas-chromatographischen Trennflüssigkeit
SummaryFrom the theory of regular solutions an equation has been deduced for the ratio of retention times. The retention ratio of two substances is given by the internal pressure of the stationary liquid and the molar volumes and the solubility parameters of the solutes. Further an approximation is described for the retention indices of solutes on different stationary liquids. The retention index of a solute on a stationary liquid is composed of the retention index on Squalane and the product of the solute polarity and the index difference of benzene on the corresponding stationary liquid. These relations yield rules for the selection of stationary liquids.ZusammenfassungAus der Theorie der regulären Lösungen läßt sich eine Formel für das Verhältnis der relativen Retentionszeiten ableiten. Danach ist das Retentionsverhältnis zweier Stoffe in regulärer Lösung durch den inneren Druck der stationären Flüssigkeit und durch Molvolumen und Löslichkeitsparameter der zu trennenden Stoffe festgelegt. Weiter wird eine Näherung im Indexsystem beschrieben, wonach der Retentionsindex einer Substanz auf verschiedenen Trennsäulen sich aus dem Retentionsindex des Stoffes auf Squalan und dem Produkt aus Stoffpolarität und der Indexdifferenz für Benzol auf der jeweiligen Trennflüssigkeit zusammensetzt. Aus beiden Beziehungen ergeben sich Regeln zur Wahl der stationären Flüssigkeit.