Poly silica-coated

Capillary Tubes Figure 12.42 shows a cross section of a typical capillary tube. Most capillary tubes are made from fused silica coated with a 20-35-)J,m layer of poly-imide to give it mechanical strength. The inner diameter is typically 25-75 )J,m, which is smaller than that for a capillary GC column, with an outer diameter of 200-375 )J,m. 

A series of bonded poly(alkyl aspartamide) coatings was prepared on silica by analogy to the method described above. Poly(succinimide) coating was reacted with n-alkyl- and arylalkylamines in dimethylformamide to yield a series of hydrophobic adsorbents. Poly(propyl aspartamide)-silica (PolyPROPYL A) showed the maximal reversible hydrophobic binding of hemoglobin among the Cl -C5... 

Immobilization of A and B blood group oligosaccharide haptens and preparation of immunoadsorbents with specificity to anti-A and anti-B antibodies has been carried out with the use of poly acrylate-coated PG (WPG-PA) [124]. Prespacered A and B-trisaccharide-fl-aminopropylglycosides were used for the synthesis. WPG-PA (1 g) quantitatively binds both haptens (2 pinole) whereas some other activated affinity supports (for example, CNBr-Sepharose 4B) do not. On the other hand, glycidoxypropyl-silica binds prespacered haptens completely but these materials reveal no specific adsorptivity. 

Senarath-Yapa MD, Saavedra SS, Aspinwall CA, Roberts DL (2004) Poly(lipid)-coated, bye doped silica nanoparticles for biological sensing applications. Abstr Pap Am Chem Soc 227 U849-U849... 

Silica coated with poly(ethyleneimine) is crosslinked with ethylenediaminetetracar-boxylic acid mediated by EDCCl. The sorbent exhibits a high capacity for metal com-plexation and a good stability in an acidic medium. ... 

Fig. 28 Schematic of a poly(lipid)-coated silica nanoparticle. Fluorescent dyes are encapsulated in the sol-gel silica core the nanoparticle is then coated with cross-linked bis-SorbPC doped with...

Figure 16. Structure of coated silica for HPIC and for the extraction of radioactive lanthanides (A) poly-NBE coating, (B) poly(7-oxanorbornene-2,3-dicarboxylic acid)-Woc/ -poly-NBE coating.

Another possibility is to use a capillary gel electrophoretic method that is nowadays a routinely and commercially available method for the determination of the molecular mass of proteins/polypeptides. This method can also be used for the separation of collagen chains and their polymers. For example, this procedure is described in the literamre for the separation of collagen type I a-chains and chain polymers p (dimers), and y (trimers), and also chain polymers of related molecular mass 300,(X)0 and higher (typically in the study of the formation of crosslinks). Besides commercially available kits, another option is to use fused-silica or poly vinylalcohol-coated capillaries filled with non-cross-linked polyacrylamide or hydroxyl-propylmethylcellulose in a 50 vaM Tris-glycine buffer (pH 8.8) or phosphate buffer (50 vaM, pH 2.5) (Table 1). 

Leventis N, Sadekar A, Chandrasekaran N, Sotiriou-Leventis C (2010) Click synthesis of monolithic silicon carbide aerogels from poly acrylonitrile-coated 3D silica networks. Chem Mater 22 2790-2803 Boday D J, DeFriend K A, Wilson K V Jr, Coder D, Loy D A (2(X)8) Formation of polycyanoacrylate-sUica nanocomposites by chemical vapor deposition of cyanoacrylates on aerogels. Chem Mater 20 2845-2847 Boday D J, Stover R J, Muriithi B, Keller M W, Wertz J T, DeFriend Obrey K A, Loy D A (2009) Strong, low density nanocomposites by chemical vapor depositim and polymerization of cyanoacrylates on aminated siUca aerogels. ACS Appl Mater Interfaces 1 1364—1369... 

Solid-phase microextraction (SPME) is a modified SPE procedure based on the use of a fiber, usually made of fused silica, coated with a suitable stationary phase such as poly(methylsiloxane) [13,77,148]. The fiber can be directly immersed in the water sample and maintained under stirring during the preconcentration step. Alternatively SPME fiber can be exposed to the headspace vapor over the water sample [122]. 

This was demonstrated for the series of polymers polystyrene (PS), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), and polyacrylic acid (PAA) using silica-coated and clean gold tips. The histograms of the pull-off forces (10) are shown in Figure 5, indicating that polymers with different functionalities can be chemically distinguished, provided that the mechanical properties are similar. 

Solid-phase microextractions also have been developed. In one approach, a fused silica fiber is placed inside a syringe needle. The fiber, which is coated with a thin organic film, such as poly(dimethyl siloxane), is lowered into the sample by depressing a plunger and exposed to the sample for a predetermined time. The fiber is then withdrawn into the needle and transferred to a gas chromatograph for analysis. 

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