Electrode , amperometric glucose

Scale of Operation Voltammetry is routinely used to analyze samples at the parts-per-million level and, in some cases, can be used to detect analytes at the parts-per-billion or parts-per-trillion level. Most analyses are carried out in conventional electrochemical cells using macro samples however, microcells are available that require as little as 50 pL of sample. Microelectrodes, with diameters as small as 2 pm, allow voltammetric measurements to be made on even smaller samples. For example, the concentration of glucose in 200-pm pond snail neurons has been successfully monitored using a 2-pm amperometric glucose electrode. ... 

In the area of consumer products, amperometric glucose sensors hold high potential. Industrially, process monitors for the manufacture of consumer chemicals are under development. However, replacement of defective reference electrodes, which in a laboratory environment may be trivial, may be prohibitively difficult m vivo or in an industrial process environment. 

A. Karaykin, O. Gitelmacher, and E. Karaykina, Prussian blue-based first-generation biosensor. A sensitive amperometric electrode for glucose. Anal. Chem. 67, 2419—2423 (1995). 

J. Pei and X. Li, Amperometric glucose enzyme sensor prepared by immobilizing glucose oxidase on CuPtC16 chemically modified electrode. Electroanalysis 11, 1266-1272 (1999). 

H. Tang, J. Chen, S. Yao, L. Nie, G. Deng, and Y. Kuang, Amperometric glucose biosensor based on adsorption of glucose oxidase at platinum nanoparticle-modified carbon nanotube electrode. Anal. Biochem. 331, 89-97 (2004). 

The potentialities offered by chemical processes catalyzed by enzymes immobilized in a polymeric matrix are obvious and are now successfully utilized in various ways [6, 13, 16, 17, 40, 43,44, 50, 58, 61], This idea was introduced into electroanalytical chemistry by Clark and Lyons [9], who proposed a glucose electrode, with glucose oxidase immobilized between cuprophane membranes and with amperometric determination of the hydrogen peroxide formed by the reaction... 

In amperometry, the current at the working electrode is proportional to analyte concentration. The amperometric glucose monitor generates H202 by enzymatic oxidation of glucose and the H202 is measured by oxidation at an electrode. A mediator is employed to rapidly shuttle electrons between electrode and analyte. 

F. Palmisano, R. Rizzi, D. Centonze and P.G. Zambonin, Simultaneous monitoring of glucose and lactate by an interference and cross-talk free dual electrode amperometric biosensor based on electropolymerized thin films, Biosens. Bioelectron., 15(9-10) (2000) 531-539. 

R. Garjonyte and A. Malinauskas, Amperometric glucose biosensors based on Prussian blue and polyaniline glucose oxidase modified electrodes, Biosens. Bioelectron., 15 (2000) 445-451. 

A miniaturized planar amperometric glucose sensor has been created on Sapphire substrates. Thin film titanium-gold electrodes are covered with an enzyme layer which is patterned by a lift-off technique [66]. This sensor exhibits a fast response time of 30 seconds but the linear measuring range is poor. 

Amperometric response currents from the PPy-GOD film electrode with glucose were also recorded after overoxidizing the electrode at 1.0 V for a certain period of time. The results showed that the overoxidation of the PPy-GOD film did not decrease the amperometric response current of the PPy-GOD film electrode with glucose. The results suggested that the GOD, which was immobilized on the GC electrode surface by the electropolymerization of the pyrrole with GOD, remained on the electrode surface after the overoxidation of the PPy-GOD film. 

On-wafer membrane deposition and patterning is an important aspect of the fabrication of planar, silicon based (bio)chemical sensors. Three examples are presented in this paper amperometric glucose and free chlorine sensors and a potentiometric ISRET based calcium sensitive device. For the membrane modified ISFET, photolithographic definition of both inner hydrogel-type membrane (polyHEMA) and outer siloxane-based ion sensitive membrane, of total thickness of 80 pm, has been performed. An identical approach has been used for the polyHEMA deposition on the free chlorine sensor. On the other hand, the enzymatic membrane deposition for a glucose electrode has been performed by either a lift-off technique or by an on-chip casting. 

Su, L., Qiu, X. P., Guo, L. H., Zhang, F. H. and Tung, C. H. (2004), Amperometric glucose sensor based on enzyme-modified boron-doped diamond electrode by cross-linking method. Sensor Actuator B, 99(2-3) 499-504. 

Willner, I., Doron, A., Katz, E., Levi, S., and Frank, A. J. Reversible associative and dissociative interactions of glucose oxidase with nitrospirppyran monolayers assembled onto Au-electrodes Amperometric transduction of recorded optical signals. Langmuir 1996, 12, 946-954. 

Amperometric glucose biosensors based on co-immobiUzation of GOx with [Os(bpy)2(4-VP)ioCl]Cl in electrochemically generated polyphenol film [72]. A bilayer electrode in which Os-pol3nmer is first adsorbed on a Pt electrode and then electrochemically deposited on polyphenol-GOx fihn showed sensitivity of 1.63-1.79 /jA/cm /mM to 20 mM glucose at 0.4 V and 6-7 mM. Low background current and less interference by common electroactive compounds were noted. 

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