Effect of liquid-phase diffusion resistance on retention time in gas-liquid chromatography

1982 ◽  
Vol 54 (2) ◽  
pp. 326-328 ◽  
Author(s):  
Jan Chan. Huang ◽  
Richard. Madey
Keyword(s):  
Liquid Chromatography ◽  
Liquid Phase ◽  
Retention Time ◽  
Diffusion Resistance ◽  
Gas Liquid Chromatography ◽  
Phase Diffusion

GAS–LIQUID CHROMATOGRAPHY OF SOME FLAVONOID COMPOUNDS AND HYDROXY DIPHENYLS

1962 ◽  
Vol 40 (6) ◽  
pp. 1123-1129 ◽  
Author(s):  
N. Narasimhachari ◽  
E. Von Rudloff
Keyword(s):  
Hydrogen Bonding ◽  
Liquid Chromatography ◽  
Liquid Phase ◽  
Linear Relationship ◽  
Retention Time ◽  
Gas Liquid Chromatography ◽  
Isolation And Identification ◽  
Flavonoid Compounds ◽  
Retention Characteristics ◽  
The Difference

Gas–liquid chromatography of the methyl ethers of 36 flavones, flavanones, isoflavones, and chalkones, 2 chromones, and 9 hydroxy diphenyls was carried out, using SE-30 silicone polymer as liquid phase. The results obtained show that this technique can be used for the separation, isolation, and identification of milligram amounts of these compounds. The influence of methylation, acetylation, and hydrogen bonding was demonstrated and is discussed. Dehydration of a 2-hydroxyisoflavanone to the corresponding isoflavone and isomerization between some flavanones and chalkones were encountered. No linear relationship between the number of substituents and retention time was obtained, indicating that substituents at different positions of a flavonoid nucleus influence the retention characteristics in a different manner. This was especially noticeable with some 3- and 5-substituted flavones, but in other instances the difference in retention times was also sufficient to differentiate between position isomers.

THE SEPARATION OF SOME TERPENOID COMPOUNDS BY GAS–LIQUID CHROMATOGRAPHY

1960 ◽  
Vol 38 (5) ◽  
pp. 631-640 ◽  
Author(s):  
E. von Rudloff
Keyword(s):  
Liquid Chromatography ◽  
Polyethylene Glycol ◽  
Liquid Phase ◽  
Diatomaceous Earth ◽  
Solid Support ◽  
Gas Liquid Chromatography ◽  
Polyphenyl Ether ◽  
Liquid Phases ◽  
Degree Of Separation ◽  
Separation Of Mixtures

A study has been made of the degree of separation of mixtures of some terpene hydrocarbons, some of their oxygenated derivatives, two sesquiterpene alcohols, and three monophenols on a variety of columns. Temperature and sample size affected the degree of separation and the solid support Chromosorb W, a calcined diatomaceous earth, was found to combine the advantages of Celite and C-22 firebrick without causing decomposition of the sample at higher temperatures. When Craig polyesters were used as liquid phases, separations equal to those obtained on polyethylene glycol were realized with the added advantage that these produced columns which are stable at 190 to 220 °C. Consequently, sesquiterpene alcohols and monophenols were also separated successfully. Another useful liquid phase for both low and high temperatures was found in a meta-linked polyphenyl ether. Squalene was found to be an efficient liquid phase for the separation of terpene hydrocarbons at 130 °C and lower. The possible application of the present findings for preparative work is discussed.

Gas—Liquid Chromatographic Measurement of Guanidino Acids

1975 ◽  
Vol 21 (7) ◽  
pp. 838-843 ◽  
Author(s):  
Harini Patel ◽  
Burton D Cohen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Liquid Chromatography ◽  
Liquid Phase ◽  
Magnetic Resonance ◽  
Gas Liquid Chromatography ◽  
Butyl Esters ◽  
Silicone Liquid ◽  
Chromatographic Measurement ◽  
Liquid Chromatographic

Abstract We present a method for separating and measuring guanidino acids by gas—liquid chromatography. Compared to ion-exchange techniques, this system is faster, more sensitive, requires smaller sample volumes, is independent of colorimetric reactions, and permits simultaneous determination of both amino and guanidino acids. N-Trifluoroacetyl-n-butyl esters are formed and then are separated by using a column containing a mixed silicone liquid phase coated on Chromosorb W-HP. Analytical recoveries from plasma ranged from 86 to 112% and were optimal when purification and derivatization were done without prior protein precipitation. Speculations as to the cause of this interference by protein include coprecipitation, protein-binding, and cyclization of the guanidines in the acids used for denaturation. Evidence presented suggests that all three occur: ultrafiltrability is diminished in the presence of protein and nuclear magnetic resonance demonstrates cyclization of some of these esters.

Classification of some dermatophytes by pyrolysis–gas–liquid chromatography

1973 ◽  
Vol 19 (4) ◽  
pp. 403-407 ◽  
Author(s):  
J. W. Carmichael ◽  
Awatar S. Sekhon ◽  
Lynne Sigler
Keyword(s):  
Liquid Chromatography ◽  
Mating Type ◽  
Retention Time ◽  
Gas Liquid Chromatography ◽  
Mating Types ◽  
Random Drift ◽  
Characteristic Peak ◽  
Pyrolysis Gas ◽  
Arthroderma Benhamiae

Samples from dried colonies of 21 strains of Nannizzia and Arthroderma were analyzed by pyrolysis–gas–liquid chromatography. Characteristic peak patterns produced by all the strains were used as markers to correct random drift in retention time so that corresponding peaks in different pyrograms could be homologized. Variation in sample size was compensated for by comparing peaks on each pyrogram with a particular major component and scoring them simply as 0 (absent), 1 (small), or 2 (large). Proximities were calculated and analyzed for clusters by the TAXMAP procedure. The analysis always grouped replicate samples together in the same cluster. Opposite mating types of the same species were sometimes placed in the same cluster and sometimes in separate clusters. The (+) mating type of Arthroderma benhamiae was placed in a cluster with both mating types of Nannizzia gypsea and N. obtusa, while the (−) mating type replicates of A. benhamiae were placed in a cluster by themselves. Finding a greater difference between pyrograms of different mating types of one species than between pyrograms of different species was unexpected and requires further investigation.

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