Electrochemical Functionalisation

20 mg/mL polyethyleneoxide, 10 mg/mL lithium perchlorate in a mixture of metha-nol/water (v/v 4 1). PVC-LPC 20 mg/mL polyvinylchloride, 2 mg/mL lithium perchlorate in tetrahydrofuran. It is apparent that by changing the composition of the polymer matrix, it is possible to shift the threshold voltage of the transistors. The inset shows the schematic of the fabricated FET (S - source, D - drain). 

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Many compounds which are neither reduced nor oxidized in the available potential range or for which the signals acquired are not suitable for analytical purposes can be converted into electroactive substances via chemical or electrochemical functionalisation. ... 

Electrochemical Properties of Functionalised Polymer Bead Films ... 

To further suppress the insertion of dyes into the channels from the substrate side, the channels can be sealed on one side by adsorption of a polymer onto the substrate [48,49]. Alternatively, stopcocks can be functionalised specifically with electroreactive constituents like ethynylic [50] vinylic [51], or pyrrolic groups [52,53]. The substrate serves as electrode under the influence of an electrochemical potential and only the adjacent heads of the stopcocks react to form a covalently cross-linked structure. The stopcocks are then removed from the other side of the crystals to unblock the channels for the dye insertion. 

S. Centi, S. Laschi and M. Franekand M. Mascini, A disposable immuno-magnetic electrochemical sensor based on functionalised magnetic beads and carbon-based screen-printed electrodes (SPCEs) for the detection of polychlorinated biphenyls (PCBs), Anal. Chim. Acta, 538 (2005) 205-212. 

Further studies, including electrochemical redox-state transformations, involving other double-stranded helicates derived from analogously functionalised quater-pyridine, quinquepyridine and septipyridine, have also been reported. 

Enzyme sensors can measure analytes that are the substrates of enzymatic reactions. Thermometric sensors can measure the heat produced by the enzyme reaction [31], while optical or electrochemical transducers measure a product produced or cofactor consumed in the reaction. For example, several urea sensors are based on the hydrolysis of urea by urease producing ammonia, which can be detected by an ammonium ion-selective ISE or ISFET [48] or a conductometric device [49]. Amperometric enzyme sensors are based on the measurement of an electroactive product or cofactor [50] an example is the glucose oxidase-based sensor for glucose, the most commercially successful biosensor. Enzymes are incorporated in amperometric sensors in functionalised monolayers [51], entrapped in polymers [52], carbon pastes [53] or zeolites [54]. Other catalytic biological systems such as micro-organisms, abzymes, organelles and tissue slices have also been combined with electrochemical transducers. 

C76 fullerene [135113-15-4] M 912.85, melts above 350". It is now available commercially. After the sequential removal of and C70 fullerenes from soot extracts (see above) on gel permeation columns (e.g. Buckyclutcher 1 column), C76 and higher fullerenes are obtained. These are further separated on a Tridait-TriDNP functionalised silica column. After two HPLC runs on a Cjg reverse phase (Vydac 201 TP C,g) column and eluting with 1 1 MeCN/toluene, pure C76 fuUerene is obtained. The identity is confirmed by HPLC/GPC system with Waters 600E UV/VIS detection, mass and NMR spectroscopy. [Seleque et al. In Kadish and Ruoff (Eds) Fullerenes Recent Advances in the Chemistry and Physics of Fullerenes and Related Mfltena/i The Electrochemical Soc. Inc, Pennington, NJ, 1994 ISBN 1566770823, Diederich Whetten Acc Chem Res 25 119 1992, Diederich et al. Science 254 1768 1991.]... 

As can be seen from Eqs. (5), (2) and (3), the reaction of electrochemical enzyme-based biosensors relies on different mechanisms the right transport of substrate, co-substrate and products. For venous blood measurements or in vivo applications the proper transport of oxygen is not maintained. Therefore, new microgel formulation has to be used based on functionalised polymers. 

Polsky, R., Gill, R., Kaganovsky, L., Willner, I. (2006). Nucleic acid-functionalised Pt nanoparticles catalytic labels for the amplified electrochemical detection of biomolecules. Anal Chem 78, 2268-2271. 

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