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Investigation of thermal and analytical properties of two nematic liquid crystals by gas chromatography (1995)

Berdagué, P. ; Perez, F. ; Courtieu, J. ; [et al.]

Springer

Chromatographia 40 (1995), S. 581-586

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ISSN: 1612-1112

Keywords: Gas chromatography ; Liquid crystals ; Internal and external NO2 compounds ; Transition temperature ; Analytical properties

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Summary Thermal and analytical properties of two liquid crystals containing internal [2-nitro, 3-methyl 4-(4-heptylbenzoyloxy) 4′-methylazobenzene] and external NO2 [2,3-dimethyl 4-(4-heptylbenzoyloxy) 4′-nitroazobenzene] have been investigated by gas chromatography. Transitions temperatures are determined by inverse gas chromatography using standard columns. Good agreement with values determined by differential scanning calorimetry are found. Analytical capabilities of the two liquid crystals are shown in glass capillary columns. Compared to examples in the literature, the crystals used separated different kinds of solutes. In addition, high molecular mass solutes were eluted at relatively low temperatures. Typical separations are observed for hydrocarbon positional isomers, aromatic hydrocarbons, geometric isomers, and volatile aroma compounds. Comparison between the performance of internal and external, NO2-liquid crystals is made.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02290272

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Gas chromatographic properties of two thermotropic Poly(L-glutamates) with long alkyl side chains (1996)

Meddour, A. ; Courtieu, J. ; Abdelhadi, W. ; [et al.]

Springer

Chromatographia 43 (1996), S. 387-392

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ISSN: 1612-1112

Keywords: Gas chromatography ; Poly(L-glutamate) ; Cholesteric liquid crystal ; Properties as stationary phases

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Summary Comparative gas chromatographic properties of two thermotropic Poly(L-glutamates) with long alkyl side chains (10 and 16 carbons called Poly 10 and Poly 16 respectively) are studied. Their thermal properties were established with differential scanning calorimetry (DSC) and gas chromatography. They present a cholesteric liquid crystal in a large temperature range. The chromatographic separation abilities of the two polymers in the liquid crystal state were studied using capillary glass columns. Interesting analytical performances were obtained in different fields: isomeric separation of alkanes, aromatics, polyaromatics, volatile aroma compounds and cis and trans isomers. Some differences were noticed in their behaviours; 2 and 3-methyloctane and xylene isomers are separated only on Poly 10 while limonene and eucalyptol are separated only on Poly 16.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02271016

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HPLC of acetylsalicylic (ASA) and salicylic acids (SA): Optimal conditions for trace analysis of SA in ASA (1982)

Menouer, M. ; Bouabdellah, F. ; Ghernati, H. M. ; [et al.]

Weinheim : Wiley-Blackwell

Journal of High Resolution Chromatography 5 (1982), S. 267-268

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ISSN: 0935-6304

Keywords: Liquid chromatography, HPLC ; Reverse phase mode ; Optimization of mobile phase ; Detection of 0.1% of salicylic acid in acetylsalicylic acid ; Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Additional Material: 3 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jhrc.1240050509

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Chromatographic mechanisms of coated porous polymers: Chromosorb 102 coated with squalane (1984)

Aider, A. ; Devallez, B. ; Guermouche, M.-H.

Weinheim : Wiley-Blackwell

Journal of High Resolution Chromatography 7 (1984), S. 222-224

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ISSN: 0935-6304

Keywords: Gas chromatography ; Interface ; Partition ; Adsorption ; Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Additional Material: 2 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jhrc.1240070413

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Cryogenic retention mechanism of some si-or bonded stationary phases: Comparison with conventional coated stationary phases (1983)

Boudah, S. ; Abdeddaim, K. ; Guermouche, M. H.

Weinheim : Wiley-Blackwell

Journal of High Resolution Chromatography 6 (1983), S. 281-282

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ISSN: 0935-6304

Keywords: Gas chromatography ; Si-OR, bonded stationary phase ; Change of physical state ; Retention mechanism ; Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Additional Material: 3 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jhrc.1240060514

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Gas chromatographic study of the thermal and analytical properties of a nematic luquid crystal and its cupric complex (1995)

Berdagué, P. ; Perez, F. ; Courtieu, J. ; [et al.]

Weinheim : Wiley-Blackwell

Journal of High Resolution Chromatography 18 (1995), S. 304-308

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ISSN: 0935-6304

Keywords: Gas chromatography ; Nematic liquid crystal ; Cupric complex ; Transition temperatures ; Analytical performance ; Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The nematic compound N-4-(2′-(4″-dodecyloxybenzoyloxy)-4′-do-decyloxy)azobenzenyl-4-dodecyloxysalicylideneimine, known as LH, and its cupric complex, bis[N-4-(2′-(4″-dodecyloxybenzoyloxy)-4′-dodecyloxy)azobenzenyl-4-dodecyloxysalicylidene]iminato of copper (II), known as CuL2 have been used as stationary phases for gas chromatography. The thermal properties of LH and CuL2 have been determined with conventional metal columns, using n-alkanes as solute probes. Plots of In V0g against 1/T clearly show the temperature transitions of LH and CuL2. The analytical capabilities of the two stationary phases were established by use of 25 m glass capillary columns. Satisfactory separations were obtained for positional hydrocarbon and halocarbon isomers, aromatic and polyaromatic compounds, and volatile essential oil constitutents.

Additional Material: 8 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jhrc.1240180508

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