scholarly journals Thermal and Hydrothermal Treatment of Silica Gels as Solid Stationary Phases in Gas Chromatography

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ashraf Yehia El-Naggar
Keyword(s):  
Gas Chromatography ◽  
Stationary Phase ◽  
Hydrothermal Treatment ◽  
Aromatic Hydrocarbons ◽  
High Efficiency ◽  
Silica Surface ◽  
Stationary Phases ◽  
Silica Gels ◽  
Good Separation ◽  
Treatment Techniques

Silica gel was prepared and treated thermally and hydrothermally and was characterized as solid stationary phase in gas chromatography. The characteristics have been evaluated in terms of polarity, selectivity, and separation efficiencies. These parameters were used to assess the outer silica surface contributions and the degree of surface deactivation brought about by different treatment techniques. The parent silica elutes the paraffinic hydrocarbons with high efficiency of separation and elutes aromatic hydrocarbons with nearly good separation and has bad separation of alcohols. The calcined silica at 500°C and 1000°C has a pronounced effect on the separation of aromatic hydrocarbons compared with the parent silica and hydrothermal treatment of silica. With respect to alcohols separation, the obtained bad separations using treated and untreated silica reflect the little effect of the thermal and hydrothermal treatment on the silica surface deactivation.

Carboxylated cyclofructan 6 as a hydrolytically stable high efficiency stationary phase for hydrophilic interaction liquid chromatography and mixed mode separations

2016 ◽  
Vol 8 (31) ◽  
pp. 6038-6045 ◽  
Author(s):  
Yadi Wang ◽  
M. Farooq Wahab ◽  
Zachary S. Breitbach ◽  
Daniel W. Armstrong
Keyword(s):  
Liquid Chromatography ◽  
Benzoic Acid ◽  
Stationary Phase ◽  
Mixed Mode ◽  
High Efficiency ◽  
Stationary Phases ◽  
Hydrophilic Interaction Liquid Chromatography ◽  
Hydrophilic Interaction

Stationary phases composed of native cyclofructan 6 (CF6) and benzoic acid modified CF6 were synthesized and evaluated for hydrophilic interaction liquid chromatography (HILIC).

Preparation and capillary gas chromatography of polymethyl- and ethylmethylbiphenyls and polymethyldiphenylmethanes

1984 ◽  
Vol 49 (1) ◽  
pp. 218-230 ◽  
Author(s):  
Jan Novrocík ◽  
Marta Novrocíková ◽  
Jaroslav Foniok
Keyword(s):  
Gas Chromatography ◽  
Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Capillary Gas Chromatography ◽  
Stationary Phases ◽  
Correlation Coefficients ◽  
Polar Medium ◽  
Aromatic Substrates ◽  
Alkyl Groups ◽  
Isomeric Methyl

Trimethyl-, tetramethyl-, and ethylmethylbiphenyls with the alkyl groups at one aromatic ring have been prepared by the Gomberg reaction and identified by capillary gas chromatography. The products are either chemical individua or mixtures of up to three isomers depending on choice of the aromatic hydrocarbon. The ethylmethylbiphenyls have been prepared as mixed standards only. Most aromatic hydrocarbons used in the Gomberg reaction have been prepared by combination of rectification and sulphonation procedures. The HMO method has been used for calculation of the values of the radical superdelocalizabilities at individual centres of the 1,2,4- and 1,2,3-trimethylbenzene molecules which have been compared with product composition of the Gomberg reactions of these hydrocarbons. Reactivities of the aromatic substrates used in the Gomberg reaction have been compared by the competition technique. Capillary gas chromatography using three columns wetted with non-polar , medium, and polar stationary phases has been used to determine the Kovats indexes of the hydrocarbons prepared and parameters of the linear dependences IApiez.L = k.Istat.phase(2) + q (with the corresponding correlation coefficients). From the elution data of the isomeric methyl- and ethylbiphenyls the increments have been derived for methyl and ethyl groups, and possibility of prediction and assessment of the Kováts indexes of polyalkybiphenyls and dimethyldiphenylmethanes is discussed.

Analysis of hydroformylation products of higher n-alkenes by capillary gas chromatography

1985 ◽  
Vol 50 (8) ◽  
pp. 1808-1818 ◽  
Author(s):  
Ján Krupčík ◽  
Dušan Repka
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Reaction Mechanism ◽  
Stationary Phase ◽  
Capillary Gas Chromatography ◽  
Stationary Phases ◽  
Capillary Columns ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry

A mixture of alcohols obtained by hydroformylation of C10-C13 n-alkenes was analyzed by capillary gas chromatography using Carbowax 20M stationary phase, and acetates prepared from the alcohols were analyzed on capillary columns using Carbowax 20M and Apiezon L stationary phases. The capillary gas chromatography and gas chromatography-mass spectrometry treatment gave evidence that all of the 24 alcohols that could form by the hydroformylation reaction mechanism were present.

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