The Thermodynamics of Chromatography - The Interactive Energy Difference Between that of a Methylene Group and that of a Methyl Group with an Alkane Stationary Phase > Page 14

The Interactive Energy Difference Between that of a Methylene Group and that of a Methyl Group with an Alkane Stationary Phase

Before discussing some examples of the use of thermodynamics in chromatography, it should be pointed out that there is an immense amount of accurate and precise retention data available in the literature. Unfortunately, much of this data was published before 1980 and, thus, is not identified by many computer search engines and needs to be found by older and conventional literature search methods. So much retention data has been published that, in the thermodynamic study of distribution systems, additional measurements are frequently unnecessary, as pertinent data is already available. Data collection started in the 1950s but the most prolific period was between the mid sixties to the mid seventies. The data generated in this period was particularly accurate and precise and that reported by Purnell and his coworkers from Cambridge University England, Martireandhis group from Georgetown University, Washington U.S.A., Lochmüller and his group from Duke University Durham U.S.A. and Karger and his group from Northeastern University Boston U.S.A are strongly recommended as ideal for thermodynamic analysis. Consequently, research into the thermodynamics of chromatographycanbe carried out comprehensively and relatively inexpensively because of the enormous mount of precise and accurate data that is conveniently available from the early chromatography literature. In addition, the research laboratories of British Petroleum and Shell invested large sums of money in the accurate and precise GC measurement of the retention properties of a wide range of alkanes, cyclic alkanes, alkenes and aromatics (having carbons numbers up to C30) on a range of dispersive, semi polar and polar stationary phases. This data was, (at least up to a few years ago) readily available from the research laboratories of BP-Sunbury and Shell-Thornton.