High-temperature Stationary Phase Research Articles

High temperature stationary phase of polysiloxane containing N,N′-bis(diphenylsilyl) tetramethylcyclodisilazane for gas chromatography

A polysiloxane copolymer (P(BPTMC)-alt-ODMS) containing N,N′-bis(diphenyl-silyl) tetramethylcyclodisilazane (BPTMC) was used as stationary phase in gas chromatography with high thermal stability.

Application of High-Temperature High-Resolution Gas Chromatography to the Analysis of -Cyclodextrin Derivatives

Short (3 m) columns are used with high-temperature stationary phases in analyses of reaction mixtures and isolated single species of β-cyclodextrin derivatives. The stationary phases are 5% phenyl-95% methylpolysiloxane and 30% diphenylpolysiloxane-40% sildiphenylene-ether-30% dimethyl polysiloxane; the latter phase is the best phase for the resolution of mixtures of positional isomers of β-cyclodextrin derivatives.

Pentafluorobenzoic anhydride as a derivatizing agent for alcohols and hydroxy fatty acid methyl esters detected by electron capture in gas chromatography

Pentafluorobenzoate derivatives of primary and secondary alcohols have been prepared using pentafluorobenzoic anhydride. The gas chromatographic properties of the homologous series of the methyl esters of 2-hydroxycarboxylic acids from C 12 to C 26 have been studied on the high-temperature stationary phase Poly-S 179. The suitability of determining trace amounts of these compounds using gas chromatography with an electron-capture detector and with electron-capture negative-ion chemical-ionization mass spectrometry is discussed.

High-temperature stationary phases based on ladder siloxane polymers

The ladder-type siloxane polymer Lestosil has been investigated as a high-temperature stationary phase for gas chromatography. Its application to the separation of different classes of chemical compounds has demonstrated the possibility of selective separation of high-boiling polar compounds without converting them into more volatile derivatives.

Evaluation of tetraalkylammonium tetrafluoroborate salts as high-temperature stationary phases for packed and open-tubular column gas chromatography

Four tetraalkylammonium tetrafluoroborate salts were evaluated as high-temperature polar stationary phases for packed and open-tubular column gas chromatography. Tetrapropylammonium and tetraoctylammonium tetrafluoroborates were found to have too limited a temperature operating range to be generally useful. Tetrahexylammonium and tetrabutylammonium tetrafluoroborates had liquid ranges from 90 to 230 and 162 to 285°C, respectively, and were studied in more detail. Both phases showed strong, selective dipole interactions these being slightly stronger for the tetrabutylammonium salt than for the tetrahexylammonium salt. The tetrabutylammonium tetrafluoroborate salt also provided higher column efficiencies, by about a factor of two, when used in packed-column gas chromatography. Retention of a wide range of organic solutes was found to occur by gas—liquid partition on the tetrafluoroborate salts. Five surface roughening techniques were evaluated for the preparation of efficient, long-lived, open-tubular columns. Whisker-modified surfaces, alone or coated with a layer of microcrystalline sodium chloride, provided columns of acceptable efficiency (2000–2500 plates per meter) and greater durability than other column types. Barium carbonate-modified surfaces provided columns of the highest efficiency but of poor durability. Columns modified with a layer of Chromosorb R6470-1 were the least efficient and of poor durability. Examples of the separation of complex mixtures on packed and open-tubular columns, coated with tetraalkylammonium tetrafluoroborates, are given to illustrate their practical utility.

Superox, a high-temperature stationary phase in gas chromatography

The possibilities of using a polyethylene glycol of molecular weight 4·10 6 (Superox-4) as a liquid phase in gas chromatography (GC) and glass capillary gas chromatography (GC) 2 have been evaluated. Superox-4 has two favourable characteristics: firstly, it can be used at very high temperatures in (GC) 2 (250–275° in continuous use and occasionally 300°) and in GC (300° in continuous use and occasionally 350°), and secondly, as a gum it adheres well to all types of glass. The polarity of Superox-4 is virtually the same as that of polyethylene glycol 20M.

Analysis of Capsaicinoids from Various Sources by Gas Chromatography

Abstract The chromatographic analysis of capsaicinoids and of oleoresin capsicum can indicate relative amounts of the pungent components and the sources of the samples. The present work describes gas chromatographic analyses of several natural and synthetic capsaicins as well as several oleoresins. Use of a high-temperature stationary phase allows good separation of the three major components of oleoresin capsicum. Differences between samples from various sources could be easily seen, both in the general pattern of the chromatograms and in the relative quantities of the major components. Analysis times were relatively short and no chemical derivatization was required.

High-temperature stationary phase for gas-liquid chromatography

High-temperature stationary phase for gas-liquid chromatography