Héberger Károly, Görgényi Miklós, Kowalska Teresa
Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest.
J Chromatogr A. 2002 Oct 11;973(1-2):135-42. doi: 10.1016/s0021-9673(02)01198-6.
Temperature dependence of the Kováts retention index (I) was measured for some aliphatic ketones and aldehydes on a poly(dimethyl siloxane) (HP-1) stationary phase. An interesting minimum (non-linearity) was observed for the I versus isothermal column temperature (T) relationships. A novel empirical model is proposed: I=A+B/T+C ln T, where A, B and Care equation constants and B/C = T(min). A detailed statistical analysis clearly shows superiority of the extended model (i.e., of this containing the logarithm of the temperature (ln T) term) over the earlier established Antoine-type reciprocal equation. The minimum temperature (and the energy like quantity=RT(min), where R is the gas constant) changes in a systematic manner. The factors effecting the (RT(min)) term are as follows: (i) this term decreases with the increase of the molecular mass of the respective oxo compounds; (ii) ketones have higher absolute values of (RT(min) than aldehydes; (iii) branching of the carbon chain lowers the mentioned (RT(min)). This enthalpy term is unambiguously bound to the polarity of solutes.
在聚（二甲基硅氧烷）（HP - 1）固定相上，测定了一些脂肪族酮和醛的科瓦茨保留指数（I）与温度的关系。观察到I与等温柱温（T）关系中存在一个有趣的最小值（非线性）。提出了一个新的经验模型：I = A + B/T + C ln T，其中A、B和C是方程常数，且B/C = T(min)。详细的统计分析清楚地表明，扩展模型（即包含温度对数（ln T）项的模型）比早期建立的安托万型倒数方程更具优越性。最低温度（以及类似能量的量 = RT(min)，其中R是气体常数）以系统的方式变化。影响（RT(min)）项的因素如下：（i）该术语随着相应含氧化合物分子量的增加而降低；（ii）酮的（RT(min)）绝对值高于醛；（iii）碳链的支化降低了上述（RT(min)）。这个焓项明确地与溶质的极性相关。
