Prospectives of polymeric liquid crystal stationary phases for capillary column gas chromatographic separations

Abstract

The liquid crystalline polysiloxane substrate offers unique selectivity when used in capillary column gas chromatography. The separation and identification of priority pollutants along with other compounds is very difficult but important. In particular, the separation of isomeric organic compounds having similar volatilities could not be obtained on capillary columns using conventional stationary phases. The complete separation of ortho, meta, and para isomers of certain disubstituted benzenes as well as polycyclic aromatic compounds was achieved on a capillary column using a liquid crystalline polysiloxane stationary phase. The complete separation of octachlorodibenzodioxin from octachlorodibenzofuran was also obtained on this column which is not possible on columns of identical lengths using conventional stationary phases. The separation of polycyclic aromatic compounds in a complex sample of airborne particulate matter extract on the liquid crystal column is demonstrated.

Cyanobiphenyl-Mesogened Liquid Crystalline Polymer Bonded on Silica as the Stationary Phase with Shape and Polarity Recognition for LC

“…Elemental analysis was performed on a Vario EL (Elementar, Germany). 1 H NMR was measured on an AM-400 nuclear spectrometer using CD 3 Cl as a reference. Gel permeation chromatography (GPC) was carried out on an Agilent 1200 chromatograph equipped with polystyrene gel columns and a differential refractive index detector at 30°C.…”

“…Hundreds of papers including many reviews have been published in the past few decades [1][2][3]. Although not universal for applications, LCSPs possess merits in the separation of geometric isomers over traditional stationary phases.…”

Étude par chromatographie en phase gazeuse de nouveaux composés cristaux liquides nématiques à chaîne latérale

“…Les composés mésogènes utilisés en chromatographie en phase gazeuse (CPG) sont monomériques [8][9][10], de type nématique, cholestérique [11] ou smectique [12]. Cependant, ces dernières années, l'intérêt s'est porté sur la synthèse de cristaux liquides polymériques [13] et de composés mésogènes substitués latéralement par des substituants flexibles [14].…”

Comparison of high resolution gas chromatography with electron impact and negative ion mass spectrometry detection for the determination of coplanar polychlorobiphenyl congeners in sewage sludges

“…For the final determination coplanar PCB are separated by high resolution capillary gas chromatography (HRGC) on suitable columns. Frequently used are bonded non polar methylpolysiloxane (DB-1), 5% phenyl methylpolysiloxane (DB-5), 50% phenyl methylpolysiloxane (DB-17) phases or columns specially intended for the separation of planar molecules like the smectic (liquid crystalline polysiloxane) phase [10,11]. Detection of these chlorinated compounds are mainly carried out with electron capture detection (ECD) or mass spectrometry (MS) applying electron impact (EI) ionization in the single ion monitoring mode (SIM).…”