Phases For Capillary Gas Chromatography Research Articles

Influence of some inorganic salts on the polarity of apolar polymer phases in capillary gas chromatography

AbstractDifferent stationary phases were prepared by mixing a series of inorganic salts with dimethylsiloxane polymer (SE‐30) and then tested by capillary gas chromatography. It was demonstrated that the polarity (as evaluated by measurement of Rohrschneider constants) of the mixed stationary phases, which is inferior or equal to that of a medium‐polar OV‐25 phases, reached even lower values than SE‐30 alone. The influence of NaF, NaCl, NaBr, AgNO3, and other inorganic salts on the polarity of capillaries is reflected by a better resolution and shorter retention time of cis/trans isomers of fatty acid methyl esters (FAMES) as well as positional isomers of triglycerides.

Löseverhalten kristallin-flüssiger phasen in der kapillar-gaschromatographie : I. Lösseigenschaften nematischer oximester

Solution behaviour of liquid crystal phases in capillary gas chromatography. I. Solution properties of nematic oxime esters The use of capillary columns to investigate the solution properties of a homologous series of liquid-crystalline-4- n-pentyl-acetophenone-(O-4- n-alkoxybenzoyloximes) was very favourable. A number of disubstituted isomeric benzenes could be completely separated in columns of a length of only 8 to 27 m. The alternations of partial molarenthalpies and entropies of solution were discussed in terms of the Maier-Saupe theory. The p-isomers show in the nematic ranges in most cases the largest partial molar enthalpies of solution and the smallest solute activity coefficients. Because of the shape, the polarizability and polarity, the p-isomers have the largest translational energy loss in comparisons with o- and m-isomers