Chromatographic determination of the thermodynamic adsorption characteristics of saturated tricyclic hydrocarbon isomers using capillary columns with graphitized carbon black

Summary Due to their high efficiency capillary columns packed with graphitized thermal carbon black (GTCB) permit to realize high selectivity in the chromatographic separation of isomers on the flat surface of this adsorbent. However, the increase in the efficiency is connected to a considerable increase of the pressure drop across the column which hinders the determination of the thermo-dynamic adsorption characteristics. The optimum conditions for the preparation of such columns designed both for analytical purposes and for thermodynamic measurements of the individual isomers have been established. The retention volumes for small (zero) sample size (Henry constants for adsorption on GTCB) of six isomers of tricyclo(8,4,0,0^2,7)tetradecane (perhydrophenanthrene), seven isomers of tricyclo-(7,4,0,0^2,6)tridecane (1,2-cyclopentanodecalin) and six isomers of tricyclo(7,3,0,0^2,6)dodecane have been determined. The Henry constants increase with the flattening of the isomeric molecules in these hydrocarbon series. A qualitative procedure of identification of the isomers on the basis of optimum orientation of their molecules on a flat surface has been considered.