影响Snyder方程1gk′=1gk_w—Sφ中S值的因素

Influence Factors of S in the lgk' =lgkw-Sψ

反相高效液相色谱的溶质保留行为与色谱体系性质的关系已经有人做过探讨。Snyder指出在1<k′<10的情况下,保留值与流动相组成存在下列关系 lgk′=lgk_w—Sφ式中φ为流动相中有机溶剂的体积分数,lgk_w为φ=0时的保留值,在给定的色谱体系和溶质的条件下。

The slope S in the equation lgk' = lgkw - Sψ are correlated in terms of the generalized linear soivationenergy relationshipS = A + BVb/100 + Cβm + Dαm + Enπ*where Vbis the Bondi(van der Waals) molar volume,and π*, βm and αm are the solvatochromic parameters thatmeasure solute dipolatity-polarizability, hydrogen-bondacceptor basicity and hydrogen-bond donor acidity. A,B, C, D and E are coefficients depending on a givenchromp.tographic system. By using methanol- water ortetrahydrofuran - water as mobile phase, the aboveequation can be simplified as follows:S = A + BVb/100 + CβmHow to use the above two equations predicting whether a pair of compounds which is most difficultly to be separated can be resolved in isocratic condition is discussed.