Wj. Cheong et Jd. Choi, LINEAR SOLVATION ENERGY RELATIONSHIPS IN NORMAL-PHASE LIQUID-CHROMATOGRAPHY BASED ON RETENTION DATA ON SILICA IN 2-PROPANOL HEXANE ELUENTS/, Analytica chimica acta, 342(1), 1997, pp. 51-57
We have examined the linear solvation energy relationships (LSER) base
d on the Kamlet/Taft solvatochromic polarity scales for normal phase l
iquid chromatography (NPLC), using retention data of 58 solutes in the
system composed of 2-propanol/hexane as the eluent and silica particl
es as the stationary phase. Correlation coefficients of the LSER regre
ssions for NPLC have been proven to be lower than those obtained for r
eversed phase liquid chromatography (RPLC). Furthermore, we observed i
nconsistency in LSER correlations among different solute subgroups. Ne
vertheless, the sign of each regression coefficient is in agreement wi
th chemical senses, and polarities of the stationary phase are greater
than those of the mobile phase. The polarity difference between the s
tationary and mobile phases clearly decreases with increase in mobile
phase polarity, at least for hydrogen bond related polarities. We inte
rpreted the LSER results in view of the retention process in NPLC to a
ccount for the general LSER trends and anomalies. We conclude that the
LSER methods are inappropriate in predicting solute retention in NPLC
where silica particles are used as the stationary phase, although the
LSER correlations are roughly in agreement with chemical senses.