Zur Systematik der Anomalien bei der Gelchromatographie von Kohlenwasserstoffen an Polystyrolgelen

Multimode separation of polycyclic aromatic compounds by size exclusion chromatography with poly(divinylbenzene)

“…Figure 5. Effects of molecular size and configuration on elution volume for three Isometric groups of polycyclic aromatic hydrocarbons: group 1 (11.9-12.3 A) biphenyl (1), phenanthrene (2), perylene (3), benzo-[ghi]perylene (4), coronene (5), fluorene (6), cyclopenta[def]phenanthrene (7); group 2 (14.3-14.6 A) 1,3,5-trlphenylbenzene (8), m-terphenyl (9), chrysene (10), benzo[a]pyrene (11), anthanthrene (12); group 3 (15.1-16.1 A) p-dlcyclohexylbenzene (13), plcene (14), decacyclene (15), p -terphenyl ( 16). The reference point 1/ Is at the elution volume for cataannelated PAC.…”

“…Secondly, distribution processes such as adsorption or partitioning have also been reported to contribute to nonsize elution of PAC (8)(9)(10)(11)(12)(13)(14)(15)(16). Compounds exhibiting such phenomena give elution volumes larger than predicted on the basis of molecular size.…”

“…For other SEC systems, it has been reported that elution volumes for planar, cataannelated PAC varied either directly (12,13,18) or inversely (11-13, 18, 20) with molecular size, depending on the gel and solvent combination used. For PDVB/CH2C12, Vg correlates with molecular dimensions for some nonplanar PAC 1 and 6 and 13 and 16 in Figure 5); however, planar PAC do not show a linear correspondence between size and retention volume.…”

“…Since increased electron density was implicated as a causative factor in the nonsize retention of planar PAC, an attempt was made to correlate their elution volumes with molecular parameters that reflect electron density. These parameters included the following: energies of highest occupied molecular orbitals, polarographic reduction potentials, UV band energies, and several reactivity indicators (38); resonance energy (15,23); total number of electrons (13); number of bonding electrons (9, 13); ionization potential (13); and number of -bonding carbon atoms (9).…”

“…However, for fossil fuel products and other samples composed primarily of PAC, the relationship between elution volume and molecular size is often complex, and for some samples, a satisfactory correlation cannot be made. The principal reason for this situation is the fact that for the types of gels currently in use, a number of factors other than molecular size govern the separation of PAC (8)(9)(10)(11)(12)(13)(14)(15)(16).…”