GAS-SOLID CHROMATOGRAPHY WITH SALT-MODIFIED POROUS SILICA BEADS

被引：37
作者：
ISBELL, AF
SAWYER, DT
机构：
[1] Department of Chemistry, University of California, Riverside
来源：
ANALYTICAL CHEMISTRY | 1969年 / 41卷 / 11期
关键词：
D O I：
10.1021/ac60280a003
中图分类号：
O65 [分析化学];
学科分类号：
070302 ; 081704 ;
摘要：
The differential enthalpies, entropies, and free energies of adsorption for the functional groups of substituted hydrocarbons on salt-modified porous silica beads have been determined using elution gas chromatography. The effect of adsorbent surface area and of surface modification on these thermodynamic parameters has been studied to establish optimum conditions for selective separations. Various coating salts are compared and data are presented for the functional group contributions to adsorption on Porasil C modified with Na2SO4, NaCI, LiBr, Na3PO4, Na2MoO4, NiSO4, CoSO4, AI2(SO4)3, and Cr2(SO4)3. Surface treatment of the porous silica with hexamethyldisilazane eliminates the specific interactions due to olefinic and aromatic pi electron systems. This provides a basis for evaluation of substituent contributions to aromatic pi electron density. Examples of optimized separations of difficult mixtures are presented. © 1969, American Chemical Society. All rights reserved.
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页码：1381 / &
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