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.
Contribution to the theory of the retention index system
Abstract After examining the relationship between retention index and column temperature under isothermal conditions, we have shown in a recent publication that the temperature-dependence of the retention index may generally be determined by an Antoine-type equation: After further investigation, we have established that the retention indices can be exactly calculated from programmed-temperature gas chromatography data with the following equation: A great advantage of this equation is that the data from normal hydrocarbons are not included in it.
The physico-chemical fundamentals of gas chromatographic retention on porous polymer columns: porapak Q and T
Abstract In order to explain the retention behavior of organic adsorbates on porous polymer columns in gas chromatography an attempt was made to derive characteristic functional group incremental energies for the nonpolar Porapak Q and very polar Porapak T. The total adsorption energies of a series of characteristic organic compounds were calculated and the corresponding functional group values were derived using the incremental energy equations. It has been demonstrated that Porapak T exhibits a characteristic strong interaction with the oxygen atom in alcohols, ethers and ketones and very likely has the same intensity with the hydroxyl hydrogen. Porapak Q, on the other hand, shows repulsion or weak interaction with a hydroxyl, ether or ketone oxygen but strongly interacts with the hydroxyl hydrogen. The particularly high values of the CH3 group incremental energies were calculated and discussed.