Chapter 3 Fundamentals of the Chromatographic Process The Thermodynamics of Retention in Gas Chromatography

2000 ◽  
Vol 18 (4) ◽  
pp. 323-331
Author(s):  
R. Nasuto

A binary methanol vapour/hydrogen gas mixture has been used as the mobile phase in gas chromatography. Through the use of modified frontal analysis (undertaken just before measurements of the retention of the tested analytes), it has been possible to determine the adsorption isotherm of the mobile phase modifier (methanol) under typical conditions for a chromatographic process. It was found that adsorption of the mobile phase modifier on the column packing surface caused a decrease in the retention times of all the analytes tested. Furthermore, as a result of such adsorption, an increase in the degree of hydrophobization of the column packing surface also occurred, leading to a decrease of the selectivity of the packing.


2001 ◽  
Vol 73 (6) ◽  
pp. 969-992 ◽  
Author(s):  
José Antonio García Domínguez ◽  
José Carlos Díez-Masa

The paper presents a revision of terms in the IUPAC "Nomenclature for Chromatography", Pure and Applied Chemistry, 65, 819-872, 1993. The terms revised pertain to hold-up volumes in gas, liquid, and supercritical-fluid chromatography, as well as to basic retention parameters, especially in gas chromatography. A number of related and derived definitions are described, including definitions of the terms "chromatographic process" and "chromatographic phase system". A number of the original terms were found to be misleading or superfluous, including such terms as corrected retention time, net retention time, total retention volume (time), and specific retention volume at 0 °C, and their use is strongly discouraged In Part A, the concept of the hold-up volume in chromatography is discussed. The paper also compares methods described in the literature to determine the hold-up volume. In Part B, retention parameters in gas chromatography are discussed with the aim of (i) emphasizing the physical meaning of the terms and (ii) specifying the temperatures and pressures for the terms for gas volumes and flow rates. The appendix presents revised recommendations for the terminology of some items, as well as those that are not recommended.


Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
C Bicchi ◽  
C Cagliero ◽  
C Cordero ◽  
E Liberto ◽  
B Sgorbini ◽  
...  

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