High resolution separation column Polysiloxanes

More recently, some new kinds of modified CDs have been developed which expand the range of compounds which can be resolved and also extend their use in GC. Up to now, the GC columns based on derivatized CDs have realized commercialization. Sigma corporation had developed a series of stable derivatized CD stationary phases named DEX columns for high resolution analyses of optical and positional isomers. They prepared these functional columns by adding permethylated a-CD, /3-CD or y-CD to a phenyl-containing polysiloxane stationary cophase. The DEX columns could separate chiral compounds without derivatization, and enantiomers and positional isomers are resolved by slight... 

Figure 8 FID chromatogram of antioxidants and UV stabilizers. Column PS-089, 20m x 0.3mm, glass. Carrier gas H2. (Reproduced from Blum W and Damasceno L (1987) High temperature glass capillary gas chromatography using OH-terminated polysiloxane stationary phases. Separation of antioxidants and UV stabilizers. Journal of High Resolution Chromatography and Chromatography Communications 10 472-476.)...

High-resolution gas chromatography (HRGC) has been widely applied for the determination of PCB contents in water samples [112]. PCBs can be separated on a 30-50 m fused silica capillary column with various chemically bonded stationary phases. Table 20.6 shows combinations of column lengths, stationary phases, oven temperature programs, and detectors. Polysiloxane (95% dimethyl-5% phenyl) is the most widely used stationary phase, although 5% diphenyl polydimethylsiloxane, 7% methyl-7% cyanopropyl-phenyl polysiloxane, 95% dimethyl 5% phenyl polysiloxane, 50% phenyl-methyl-polysiloxane are also used. 

Figure 5.24 shows the high-speed separation of a 20-component pesticide mixture (plus one impurity peak). The 14-m-long, 0.18-imn-i.d. thin film column ensemble consists of 7.0 m of a trifluoropropylmethyl polysiloxane column followed 7.0 m of 5% phenyl dimethyl polysiloxane column segment. For chromatogram (a), no stop-flow pulses were used, and component pairs 2,3 and 10,11 coelute. For chromatogram (b), a single 2-s wide stop-flow pulse was used to enhance the resolution of peak pair 2,3. Note that the peak pattern and resolution... 

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