Lc. Sander et al., SHAPE SELECTIVITY ASSESSMENT OF STATIONARY PHASES IN GAS-CHROMATOGRAPHY, The Journal of microcolumn separations, 6(2), 1994, pp. 115-125
Column selectivity is examined for a series of smectic liquid crystall
ine columns and is compared with methyl and C18 polysiloxane columns f
or the separation of polycyclic aromatic hydrocarbon (PAH) isomers. A
set of e,tended and condensed solute probes is described that provides
a sensitive indication of variations in column shape selectivity. Exa
mples of shape selectivity differences are presented for smectic liqui
d crystalline columns and 5% phenyl polysiloxane columns using various
PAH isomer sets. Variations in selectivity have been observed among d
ifferent smectic liquid crystalline columns, and this problem appears
more significant than for methyl polysiloxane columns. The selectivity
ratio for tetraphenylmethane and p-terphenyl provides a sensitive ind
ication of column shape selectivity, with a change in elution order oc
curring between ordered (smectic liquid crystalline) columns and non-o
rdered (methyl polysiloxane) columns. Shape selectivity differences in
dicated by this test mixture are apparent for more complex PAH isomer
mixtures. Despite stationary phase selectivity variability, smectic li
quid crystalline columns offer considerable potential for solving diff
icult separation problems involving structured solutes.