Retention behavior of alkylbenzenes as a function of temperature and mobile phase composition in reversed-phase chromatography

The reversed-phase chromatographic behaviour of a homologous series has been investigated as a function of the mobile phase composition and temperature. In general, it was found that the methylene selectivity decreased with increasing temperature and decreasing amount of water in the mobile phase. The dependence of the calculated data on the correct determination of the hold-up time is discussed. The methylene group contribution to ΔH of transfer was calculated using two different methods and the agreement was excellent. In addition, the agreement with one other reported value was excellent. Using the homologous series data, the solvent strength of the water-methanol mobile phases was calculated at different temperatures. The results were compared with the data obtained on pyrocarbon supports and the agreement was very good. Linearization methods for calculating to are discussed and the difficulties in using such procedures are described.