Electrode horseradish peroxidase-osmium

A horseradish peroxidase-osmium redox polymer-modified glassy carbon electrode (HRP-GCE) has also been applied to this analysis to improve sensitivity and reduce problems with faradic interference. Kato and colleagues (1996) employed this electrode in measurement of basal ACh in microdialysates using a precolumn enzyme reactor. This system was three to five times more sensitive than a conventional Pt electrode. ACh in rat hippocampus dialysate was quantitated at 9 5 fmol/15 pi (n = 8). ACh was analyzed in PC12 cells in a similar assay by Kim and colleagues (2004). No precolumn enzyme reactor was employed. 

Kato T, Liu JK, Yamamoto K, Osborne PG, Niwa O. 1996. Detection of basal acetylcholine release in the microdialysis of rat frontal cortex by high- performance liquid chromatography using a horseradish peroxidase-osmium redox polymer electrode with pre-enzyme reactor. J Chromatogr B 682 162-166. 

A BASJ ion-exchange microbore column (45 cm x 1 mm i.d.) 0.05 Sodium phosphate buffer of pH 8.5 containing 0.1 mM EDTA [60 pL/min]. Electrochemical at horseradish peroxidase osmium redox polymer-modified vitreous C electrodes at 0 mV versus Ag/AgCl. Rat frontal cortex dialysate samples [188]... 

Osborne and Yamamoto (1998) compared disposable, fihn carbon electrodes (PFCEs) and glassy carbon electrodes that were both modified with cast-coated Osmium-polyvinylpyrridine-wired horseradish peroxidase gel polymer (Os-gel-HRP). Sensitivities for ACh were 16 and 10 fmol/10 pi respectively. 

Acetylcholineesterase and choline oxidase Immobilization of horseradish peroxidase in the redox polymer poly (4-vinylpyridine-chlorobis-(2,2 -bipyridyl) osmium cross-linked by means of polyoxyethylene 400 diglycidyl ether on polished vitreous carbon electrodes. Response time of 30 s and maintained its sensitivity for 24 h at low substrate concentration. Responses were rectilinear up to 10 mM H202 for 100 pM choline with detection limit of 10 nM and 1 pM. [78]... 

Acetylcholineesterase and choline oxidase A glassy C electrode surface was modified with osmium poly (vinyl-pyridine) redox polymer containing horseradish peroxidase (Os-gel-HRP) and then coated with a co-immobilized layer of AChE and ChO. A 22 pL pre-reactor, in which ChO and catalase were immobilized on beads in series, was used to remove choline. The variation in extracellular concentration of ACh released from rat hippocampal tissue culture by electrical stimulation was observed continuously with the online biosensor combined with a microcapillary sampling probe. Measurement of ACh and Ch was carried out by using a split disc C film dual electrode. 

Glassy carbon electrodes have been modified with a hydrophilic, permeable film of horseradish peroxidase (HRP) covalently bound to a polyvinylpyridine polymer complexed with osmium to enhance the detection of hydrogen peroxide. Vreeke et al demonstrated that such a system could be used to quantify hydrogen peroxide (reduction at 0.0 V, SCE) produced from complex coupled reactions in their assay of NADH ... 

Figure 5. Dependence of current density on hydrogen peroxide concentration for cathodes based on different peroxidases, (open circles) NaI04 treated horseradish peroxidase (closed circles) native horseradish peroxidase (open squares) lactoperoxidase (closed squares) Aithromyces ramosus. Each electrode contains approximately 10/ g osmium redox polymer, polyethylene glycol diglycidyl ether crosslinker and 1 to 4/

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