The influence of electrolytes on the gas-liquid chromatography of hydrocarbons and alcohols

Influence of added electrolyte to the stationary phase on retention and selectivity in gas-liquid chromatography

“…Since the relative retention of ethylbenzene with respect to toluene is approximately constant (a factor of 2.34), this implies that the partition term for the benzene is contributing to the net retention volume. These trends are not surprising considering that toluene and ethylbenzene are all but effectively salted-out of the electrolyte solution at this particular salt concentration, however, benzene has a small, but finite Kl (7), which accounts for the recorded variation of relative retention for the benzene/toluene and benzene/ ethylbenzene pairs. For the chlorinated hydrocarbons, the retention patterns are much more complex.…”

“…been found true for n-alkanes, 1-alkenes, branched alkanes, and alicyclic saturated hydrocarbons on aqueous NaCl columns (7).…”

“…The stationary phase systems discussed above show high and variable selectivity characteristics for different types of solutes. Whereas the thermal stability of the aqueous electrolyte stationary phases is limited, the principles illustrated in this study would not preclude the use of less volatile solvents (7). Further, the increase in Vn°o f a solute with electrolyte addition to the stationary phase shows that the increase in Ka with additive concentration must be taken into account in studies of bulk distribution processes via chromatographic methods.…”

“…The trend in Vn°w ith % loading for dichloromethane at various electrolyte concentrations is quite different from that exhibited by n-nonane and fluorobenzene. Dichloromethane exhibits considerably more solubility than either n-nonane or fluorobenzene at all salt concentrations (7); hence, the KlVl°t erm has a considerable leveling effect on the change in Vn°w ith % loading. This is amply illustrated in Figure 3.…”

Petroleum

“…They reported that in many cases the separation was better than that achieved with capillary columns. Lithium chloride dissolved in Carbowax 400 was used by Bighi et al (171) for separation of a number of gasoline boilingrange hydrocarbons. The authors suggested that addition of electrolytes to polar phases provided an additional parameter for adjusting elution order of solutes.…”