Graphite/polystyrene

Pan et al recently reported the preparation and characterization of polystyrene/graphite composites prepared by cationic grafting polymerization. Graphite/polystyrene composites were produced with cationic grafting... 

This immunosensor-type assay uses ferrocene methanol as co-substrate (redox mediator) of glucose oxidase (GOD). The various steps of the assay, shown in Fig. 8.20, are as follows (1) Covalent immobilization of protein A on graphite-polystyrene screen-printed electrodes (SPEs) (2) Addition of the rabbit IgG to be quantified which is captured specifically by protein A (3) Addition of a biotinylated goat anti-rabbit antibody (4) Addition of avidin-GOD conjugate (5) Addition of glucose and ferrocene methanol (6) Measurement of catalytic current by flow injection immunoassay. The voltammetric current corresponds to the one-electron oxidation of the ferrocenyl group to ferricinium. The electrode can subsequently be regenerated up to 30 times. The feasibility of the assay has been demonstrated for the case of monoclonal mouse anti-human prolactin (PL) with a detection limit of 0.02 pg mL [90]. 

CFE Microcrystalline natural graphite-polystyrene composite film-... 

In the last 5 years, our attention has been paid to the development of novel electrochemical DNA biosensors based on carbon-based transducers as substrates for immobilization of DNA. Among others, following four electrodes exhibited the best properties for these purposes GCE (supplied by Metrohm, Herisau, Switzerland), microcrystalline natural graphite-polystyrene composite film-modified electrode (CFE), SPCE (supplied by Food Research Institute, Bratislava, Slovakia), and SPCE modified with single-walled carbon nanotubes (SWCNTs). 

Vyskocil V, Barek J (2012) Voltammetric DNA biosensor based on a microcrystalline natural graphite-polystyrene composite transducer. Procedia Chem 6 52-59. doi 10.1016/J.proche. 2012.10.130... 

Solid Superacids. Most large-scale petrochemical and chemical industrial processes ate preferably done, whenever possible, over soHd catalysts. SoHd acid systems have been developed with considerably higher acidity than those of acidic oxides. Graphite-intercalated AlCl is an effective sohd Friedel-Crafts catalyst but loses catalytic activity because of partial hydrolysis and leaching of the Lewis acid halide from the graphite. Aluminum chloride can also be complexed to sulfonate polystyrene resins but again the stabiUty of the catalyst is limited. 

In the present work it was studied the dependence of analytical characteristics of the composite SG - polyelectrolyte films obtained by sol-gel technique on the content of non-ionic surfactant in initial sol. Triton X-100 and Tween 20 were examined as surfactants polystyrene sulfonate (PSS), polyvinyl-sulfonic acid (PVSA) or polydimethyl-ammonium chloride (PDMDA) were used as polyelectrolytes. The final films were applied as modificators of glass slides and pyrolytic graphite (PG) electrode surfaces. 

GCB = graphitized carbon black SPME = solid-phase microextraction PDMS = polydimethylsiloxane PS = polystyrene DVB = divinylbenzene SDB = styrene-divinylbenzene. 

Besides DNA adsorption driven by a positive potential (electrostatic adsorption) DNA was also wet-adsorbed at an open circuit on a home-made polystyrene-based carbon ink [110]. This ink was prepared by a 2 3 mixture of polystyrene and graphite particles in mesitylene, and then printed on a polyester film. DNA was wef-adsorbed over the ink at 37 °C overnight. The nature of the electrode surface (graphite particles embedded in a polystyrene... 

For the SPE of the more polar aromatic sulfonates, IPs with tetralkylammonium are previously formed [85,93,94]. The combination of the formation of IP with cetyltrimethylammonium and SPE is efficacious in the extraction of benzene and naphthalene sulfonates from an aqueous environment. Good recoveries are also obtained with octylammonium acetate as the IP agent, both when it is added to the aqueous sample prior to the extraction and when it saturates the solid phase to produce an anion-exchange column [95,96]. An alternative approach is based on the use of deactivated charcoal (Carbonpack B) [96] or of chemically modified polystyrene-divinylbenzene resins [85]. Often graphitized carbon black (GCB) is used for the clean-up process of the sample [96]. 

Calorimeters Temperature measurements Graphite, water, polystyrene lOi-lO i... 

The SSMS samples are reground with a boron carbide mortar and pestle and diluted with two parts of high purity graphite. The samples with graphite are placed in polystyrene vials with two or three %-in. 

Fig.60. Chemical structure and SFM micrograph of monodendron-jacketed polystyrene (14-ABG-PS) adsorbed on highly oriented pyrolitic graphite [594]...

The system described in this investigation is polystyrene-14C adsorbed on Graphon carbon black (graphitized Spheron 6) from six solvents comprising a wide spectrum from good to poor solvent power. Well-characterized materials were selected to elucidate the conformation of polymer molecules at the solid/liquid interface. So far two models have been postulated to describe the conformation of the adsorbed polymer molecules at the solid/liquid interface (9, 13, 14, 18, 19, 21, 27). In the first model the polymer assumes a loop or coil structure in which only a fraction of the polymer segments are attached directly at the interface, and in the second model the polymer forms a relatively flat and compressed interfacial layer with many segments attached to the solid substrate. 

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