Coatings, static

The object of all coating procedures is the distribution of the stationary phase as a thin, even film that coaq>letely covers the glass surface [139,140,143,146]. Dynulc coating and static coating methods, with several individual variations are used for this purpose. 

Thixotropic suspensions are generally required for static coating due to the long column preparation time. 

Evaporation at atmospheric pressure, called the free release static coating method, has not been as widely used or evaluated as the vacuum method [146,226,234]. The experimental , arrangement is... 

The OFRR interior surface is then coated with various polymers, such as moderately polar methyl phenyl polysiloxane (OV-17) or highly polar polyethylene glycol (PEG), for the detection of different types of chemical vapors. The coating procedures are adapted from well-developed static coating procedures for GC... 

Reidy, S. Lambertus, G. Reece, J. Sacks, R., High performance, static coated silicon micro fabricated columns for gas chromatography, Anal. Chem. 2006, 78, 2623 2630... 

Instrumentation. Preliminary gas chromatographic analyses were carried out on a Perkin-Elmer 900 gas chromatograph equipped with a flame ionization detector and on a Hewlett-Packard 5730A gas chromatograph equipped with flame ionization and electron-capture detectors. The columns used were 180 cm x 2 mm ID glass columns packed with 3% SL-2100 (a methyl silicone fluid) on 80/100 mesh Supelcoport we also used 25 m X 0.25 mm ID glass capillary columns statically coated (7) with SE-52. 

The desired IL monomers are mixed with a free-radical initiator (azobisiso-butyronitrile, AIBN) in dichloromethane and coated onto the wall of the capillary column using the static coating method. The capillary is then sealed at both ends and heated to initiate polymerization. Finally, the capillary is unsealed and placed in a gas chromatograph and subsequently conditioned to remove any excess AIBN that did not completely decompose or react. 

Coating of capillary column using static coating method... 

A comprehensive study of coated anion-exchange resins provides some valuable insights [20]. Of several coating materials tested, cetyl pyridinium chloride (CPI) was found to be the most satisfactory. Static coating was employed with 1-3 x I0 M CPCI in 3 % (v/v) acetonitrile-97 % water. Coating of a polyacrylate resin (Rohm Haas XAD-8) gave sharper chromatographic peaks for anions than the more hydro-phobic PS-DVB resin (Hamilton PRP-1). 

The coating thickness of CPCI on the polyacrylate resin, and hence the ion exchange capacity, could be varied by adjusting the static coating conditions. At very low capacities (7.5 to 12.1 pequiv/g) linear plots of adjusted retention time versus exchange capacity were obtained for test ions such as fluoride, chloride, bromide and nitrate. 

There are many different static wall coatings described in the literature, recently reviewed by Horvath and Dolnik. Static coated capillaries should be treated according to the manufacturer s guidelines. Solvents such as NaOH and H2SO4 must not be used. 

Glass Capillary Gas Chromatography. For the quantitative analysis of the PAH a Varian 3700 gas chromatograph equipped, with a flame-ionization detector and coupled with a data system of Spectra Physics was used. The glass capillary columns statically coated with different stationary phases (OV 101, "SE 30 , SE 52,... 

Open tubular columns can be coated internally with the appropriate stationary phase dissolved in a suitable solvent, or, alternatively, with monomeric materials that are subsequently polymerized to form a relatively rigid polymer film on the column walls. There are two basic methods for depositing the stationary phase as a surface film on a capillary column, dynamic coating and static coating, the latter being the most commonly used. 

Factors Controlling Selectivity Open Tubular Columns Dynamic Coating Static Coating Column Regeneration Capillary Column Design and Choice Stationary Phases for the GC Separation of Chiral Substances Synopsis References Chapter 6... 

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