Stationary phases poly

Fig. 6.21. Electrochromatographic separation of benzene derivatives on monolithic capillary column prepared by UV initiated polymerization. Conditions capillary column, 100 pm i.d. x 25 cm active length stationary phase poly(butyl methacrylate-co-ethylene dimethaciylate) with 0.3 wt. % 2-acrylamido-2-methyl-l-propanesulfonic acid pore size, 296 nm mobile phase, 75 25 vol./vol mixture of acetonitrile and 5 mmol/L phosphate buffer pH 7 UV detection at 215 nm 25 kV pressure in vials, 0.2 MPa injection, 5 kV for 3 s. Peaks thiourea (1), benzyl alcohol (2), benzaldehyde (3), benzene (4), toluene (5), ethylbenzene (6), propylbenzene (7), butylbenzene (8), and amylbenzene (9).

Q,C,opium alkaloids,cocaine, caffeine Separation by means of dynamic coating HPLC Corasil I and II, dynamically coated with Poly G-300 (2%) 1000x1 Heptane-EtOH(lOtl) with different percentage of 1,2 saturation with the stationary phase Poly G-300... 

Wu and Siggia described a dynamic coating technique for the application of a liquid stationary phase - Poly G-300 - on a silica gel support. With heptane - ethanol (10 1) saturated with the stationary phase, strychnine and brucine could be separated. Polyethylene glycol coated silica gel as support has, however, been superseded by chemically bonded stationary phases. 

Capillary Stationary phase Poly(sacchaiide) Derivatives... 

Another type of synthetic polymer-based chiral stationary phase is formed when chiral catalyst are used to initiate the polymerisation. In the case of poly(methyl methacrylate) polymers, introduced by Okamoto, the chiraUty of the polymer arises from the heUcity of the polymer and not from any inherent chirahty of the individual monomeric subunits (109). Columns of this type (eg, Chiralpak OT) are available from Chiral Technologies, Inc., or J. T. Baker Inc. 

The high thermal and chemical stability of fluorocarbons, combined with their very weak intermolecular interactions, makes them ideal stationary phases for the separation of a wide variety of organic compounds, including both hydrocarbons and fluorine-containing molecules Fluonnated stationary phases include per-fluoroalkanes, fluorocarbon surfactants, poly(chlorotrifluoroethylene), polyfper-fluoroalkyl) ethers, and other functionalized perfluoro compounds The applications of fluonnated compounds as stationary phases in gas-liquid chroma... 

The mixture of deprotected amino acid derivatives in solution was then immobilized onto a polymeric solid support, typically activated 5-)xm macroporous poly(hydroxyethyl methacrylate-co-ethylene dimethacrylate) beads, to afford the chiral stationary phases with a multiplicity of selectors. Although the use of columns... 

It has been outlined by several authors that the single macromolecule may be irreversibly bound because of the large number of weakly interacting segments. The first papers on the construction of polymer-coated silica adsorbents involved the physical adsorption of water-soluble polymers. Polyethylene oxides [28, 29] and poly-/V-vinylpyrrolidone [30] are examples of the stationary phases of this type. 

With endogeneous pectic polysaccharides as substrates, the pectin methyhransferase activity was measured as radioactivity linked to oxalate-soluble polys x harides after extensive washing of microsomes with IM ethanolic NaCL Figure 2 shows that the rate of methylesterification of pectic substances was maximal on days 4 and 6 these maximum activities were observed within this period in at least five independent ejqjeriments. On the other hand, little activity was noted in young cells before day 2, and in old cells after day 9. In other words during the stationary phase the newly synthesised pectins remained unesterified because of the lack of pectin methyltransferase activity. 

In practice, it is more difficult to optimize resolution as a function of the relative retentlvity than to optimize retention. Thus, unless the mixture is very complex or contains components that are particularly difficult to separate it may be possible to optimize a particular separation using the linear equation (1.72) as demonstrated by Bttre [177]. Figure 1.13 illustrates the relative change in peak position for a polarity test mixture with two identical, serially coupled open tubular columns, coated with a poly(dimethylslloxane) and Carbowax 20 M stationary phases, as a function of their relative retentlvity on the second column. The linear relationship predicted by equation (1.72) effectively predicts the relative peak positions and indicates that a nearly... 

Figure 1.13 separation of a polarity test aixture on two 25 x 0.25 iDit I.O. (df - 0.25 aicrometers) serially coupled open tubular coluims, coated with a bonded poly(diwethylsiloxane), column i, and stabilized Cari>owax 20 M, colunn 2, stationary phases. The... 

The elution of [60]- and [70]fullerenes was measured in water-methanol as a function of temperature on a poly(octadecylsiloxane) phase.67 The retention was shown to be dependent on the surface tension of the stationary phase through a simple geometrical model in which the solute formed a cavity in the stationary phase. In affinity chromatography, it was demonstrated that low ligand density may be a requirement for specificity of binding.68... 

Pyrolysis-Gas Chromatography-Mass Spectrometry. In the experiments, about 2 mg of sample was pyrolyzed at 900°C in flowing helium using a Chemical Data System (CDS) Platinum Coil Pyrolysis Probe controlled by a CDS Model 122 Pyroprobe in normal mode. Products were separated on a 12 meter fused capillary column with a cross-linked poly (dimethylsilicone) stationary phase. The GC column was temperature programmed from -50 to 300°C. Individual compounds were identified with a Hewlett Packard (HP) Model 5995C low resolution quadruple GC/MS System. Data acquisition and reduction were performed on the HP 100 E-series computer running revision E RTE-6/VM software. 

A few synthetic helical polymers are known to act as chiral selectors.7a,918d l8k i9d i9h ancj are widely used as chiral stationary phases (CSP) in gas or liquid chromatography.73,53 Recently, it has been reported that the preference of one helical sense in isotropic solution can be induced by some interaction between optically inactive polymers and chiral solvents/additives. Examples of this include poly(n-hexyl isocyanate)18d l8k and poly(phenylacetylene)s bearing functional group.19d 19h The polysilane derivatives also show chiral recognition ability in solution at room temperature. Poly(methyl-ft-pinanylsilane) includes two chiral centers per bulky hydrophobic pinanyl side group28 and... 

Poly crystalline silicon, 9 732 Poly [cyanopropylmethylf 14%)-dimethyl(86%)] siloxane, gas chromatography stationary phase, 4 617t... 

Polystyrene-co-butylacrylate, 7 608t Poly (styrene-co-divinylbenzene), 73 113 Poly(styrene-co-vinylpyridinium methyl iodide) ionomer system, 74 480 Poly(styrenedivinylbenzene) (PSDVB) liquid chromatography stationary phase, 4 623... 

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