scholarly journals Solution Thermodynamics from Gas-Liquid Chromatography.

1966 ◽  
Vol 38 (12) ◽  
pp. 1661-1669 ◽  
Author(s):  
R. E. Pecsar ◽  
J. J. Martin
1972 ◽  
Vol 45 (6) ◽  
pp. 1638-1645
Author(s):  
D. Patterson ◽  
Y. B. Tewari ◽  
H. P. Schreiber ◽  
J. E. Guillet

Abstract It has been well established that gas—liquid chromatography (glc) can give accurate thermodynamic data on binary solutions where the components differ considerably in volatility or molecular weight. The substance of lower molecular weight (component 1) is injected into the moving gas phase and dissolves at effectively infinite dilution in the stationary liquid phase. This is formed by the higher molecular weight material, for example, squalane, biphenyl, dinonyl phthalate, glycerol, or the higher n-alkanes such as C16, C24, C36, etc. The convenience of the technique is such that activity coefficient data have already been obtained for hundreds of systems. In contrast, activity data are available for far fewer high polymer systems, in part certainly because of the need to use the laborious vapor sorption technique. While that technique gives activity data as a function of concentration, it would still be desirable to have data at infinite dilution for a variety of systems in order to test contemporary theories of polymer solution thermodynamics. Recently Guillet and coworkers have applied the glc technique to systems in which the stationary phase is a high polymer. (J. E. Guillet and coworkers refer to the gas-phase component as the molecular “probe”. This avoids the glc teminology in which that component is the solute and the stationary-phase polymer would be the solvent. This terminology is confusing to polymer chemists used to solutions where the polymer is the solute, being present at low, rather than high, concentrations.) Their primary interest has been to demonstrate the versatility of the technique in determining first- and second-order phase transitions, degrees of crystallinity, and other physical characteristics of the polymer, while the present communication considers the determination of thermodynamic quantities. It has been prompted by comments from several workers who have noted the difficulty of applying the usual thermodynamic equations of glc which yield γ1∞, the activity coefficient of component 1 at infinite dilution [Equations (5) and (6)]. The equations require an exact value of the molecular weight of component 2, making difficult their use for polymer systems. Our main objective is to resolve this problem. However, we also wish to stress the utility of the technique in providing data with which to test contemporary theories of polymer solution thermodynamics. We therefore comment on equations which directly relate experimental glc data to the interaction parameter, χ, of polymer solution thermodynamics.


1974 ◽  
Vol 24 (11) ◽  
pp. 645-654 ◽  
Author(s):  
F. Alan Barbour ◽  
Richard V. Barbour ◽  
J. Claine Peterson

1971 ◽  
Vol 67 (2) ◽  
pp. 303-315 ◽  
Author(s):  
A. J. Moolenaar ◽  
A. P. van Seters

ABSTRACT The 17-oxosteroids were estimated in the urine of 27 patients with Cushing's syndrome by gas-liquid chromatography (G. L. C.). The values of the various steroid fractions are compared with those of normal subjects, patients with thyrotoxicosis and obese subjects. The effect of the age of the patients on the diagnostic value of the invidual 17-oxosteroids and their ratios is discussed.


1992 ◽  
Author(s):  
Ronald L. Shippee ◽  
Avery A. Johnson ◽  
William G. Cioffi ◽  
James Lasko ◽  
Thomas E. LeVoyer

2020 ◽  
Vol 36 (6) ◽  
pp. 35-48
Author(s):  
D.V. Коchkin ◽  
G.I. Sobolkovа ◽  
А.А. Fоmеnkov ◽  
R.А. Sidorov ◽  
А.М. Nоsоv

The physiological characteristics of the callus cell cultures of Alhagi persarum Boiss et Buhse, a member of the legume family, widely used in folk medicine, have been studied. It was shown that the source of the explant was an important factor in the initiation of callusogenesis: more intense callusogenesis (almost 100%) was observed for explants from various organs of sterile seedlings, rather than intact plants (less than 30%). As a result, more than 20 lines of morphologically different callus cell cultures were obtained, and the growth parameters for the 5 most intensively growing lines were determined. The composition of fatty acids (FA) of total lipids and secondary metabolites in the most physiologically stable callus line Aр-207 was analyzed. Using capillary gas-liquid chromatography with mass spectrometric detection (GLC-MS), 19 individual C12--C24 FAs were identified, the main fraction of which were palmitic (~ 23%), stearic (~ 22%), linoleic (~ 14%) and α-linolenic (~ 33%) acids. The established atypical ratio of FAs (a simultaneous high content of both saturated FAs and polyunsaturated α-linolenic acid) is possibly due to the adaptation of cells to in vitro growth conditions. Phytochemical analysis of the secondary metabolites was carried out using ultra-performance liquid chromatography with electrospray ionization mass spectrometric detection (UPLC MS). Compounds belonging to different structural groups of isoflavones were found. Aglycones (calycosin, formononetin and afrormosin isomer), glucosides (formononetin glucoside), as well as esters of glucosides (malonylglycosides of calicosin, formononetin, afrormosin isomers, glycitein and genistein) were detected. These secondary metabolites are widespread in plants of the Fabaceae family; however, isoflavones are rare in representatives of the Alhagi genus. The presence of malonylated isoflavone glycosides in Alhagi spp. was shown for the first time. endemic plant species, Alhagi, in vitro cell culture, callus cell culture, isoflavones, fatty acids All studies were carried out using the equipment of the "Experimental Biotechnological Facility" and the "All-Russian Collection of Cell Cultures of Higher Plants" of IРР RAS. This work was supported by the Russian Foundation for Basic Research (RFBR), contract no.18-54-06021 (Az_a), and the Government of the Russian Federation, Megagrant Project no. 075-15-2019-1882.


1984 ◽  
Vol 30 (2) ◽  
pp. 188-191 ◽  
Author(s):  
S Yoshioka ◽  
S Saitoh ◽  
S Seki ◽  
K Seki

Abstract Six non-glucose polyols--mannose, fructose, 1-deoxyglucose, mannitol, glucitol, and inositol--were identified and evaluated in human serum and cerebrospinal fluid by gas-liquid chromatography and by gas-liquid chromatography/mass spectrometry. Concentrations of fructose, mannose, and inositol in the serum of healthy persons or children without metabolic diseases varied with age, as already reported for 1-deoxyglucose. Fructose, inositol, and glucitol concentrations in cerebrospinal fluid significantly exceeded those in serum. The method described here for determining polyols and for evaluating polyol patterns in serum, as well as the resulting data on children and healthy subjects, should be useful in investigations of the clinical and physiological significance of polyols.


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