Allmon Steven D, Dorsey John G
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA.
J Chromatogr A. 2009 Jun 26;1216(26):5106-11. doi: 10.1016/j.chroma.2009.04.068. Epub 2009 May 3.
Differences in the properties of subcritical water and conventional water/acetonitrile and water/methanol mobile phases for reversed phase separations are explored. Using van't Hoff plots enthalpies and entropies of transfer are compared among the mobile phases while linear solvation energy relationships are used to quantify contributions to retention based on a solute's polarizability, dipolarity, hydrogen bond donating ability, hydrogen bond accepting ability, and molecular size. Results suggest the presence of acetonitrile or methanol in the mobile phase may decrease dispersive interactions of the solute with the stationary phase compared to subcritical water, thereby lowering enthalpic contributions to retention. Enthalpic contributions are found to drive the retention of a methylene group in all systems studied.
探索了亚临界水与传统水/乙腈和水/甲醇流动相用于反相分离时性质上的差异。利用范特霍夫图比较了各流动相之间的转移焓和转移熵，同时使用线性溶剂化能关系基于溶质的极化率、偶极矩、氢键供体能力、氢键受体能力和分子大小来量化对保留的贡献。结果表明，与亚临界水相比，流动相中乙腈或甲醇的存在可能会降低溶质与固定相之间的色散相互作用，从而降低焓对保留的贡献。在所研究的所有体系中，发现焓的贡献驱动了亚甲基的保留。
