Minigrid electrodes

Miniaturization, 128, 163, 193 Minigrid electrode, 41, 52 Mixed-salt electrodes, 159 Modified electrodes, 118, 121 Monensin, 155 Monolayers, 117, 118, 173 Multichannel electrodes, 93, 94 Multipotentiostat, 106, 198 Mutation detection, 185... 

Figure 2.105 Optically transparent thin layer electrochemical (OTTLE) cell. A = PTFE cell body, B = 13 x 2 mm window, (C and E) = PTFE spacers, D = gold minigrid electrode, F = 25 mm window, G = pressure plate, H = gold working electrode contact, 1 = reference electrode compartment, J = silver wire, K = auxiliary electrode and L = solution presaturator. From Ranjith...

J.F. Stargardt, F.M. Fiawkridge, and H.L. Landrum, Reversible heterogeneous reduction and oxidation of sperm whale myoglobin at a surface modified gold minigrid electrode. Anal. Chem. 50, 930-932 (1978). 

The development of electrodes that exhibit optical transparency has enabled spectral observations to be made directly through the electrode simultaneously with electrochemical perturbations [19-21]. These electrodes typically consist of a very thin film of conductive material such as Pt, Au, carbon, or a semiconductor such as doped tin oxide that is deposited on a glass or quartz substrate. Miniature metal screens, minigrid electrodes in which the presence of very small holes (6-40 fim) lends transparency, have also been used. Optically transparent electrodes (OTE) and the cells that incorporate them are discussed in Chapters 9 and 11. 

Buckbee-Mears Co. 245 E. 6th St. St. Paul, MN 55101 Minigrid electrodes, especially of gold, also nickel, copper, silver... 

Fig. 9.13. Construction of two optically transparent thin-layer cells, (a) With minigrid electrode (from Ref. 22 with permission) (b) With semi-transparent tin dioxide electrode, and usable in a flow system.

Figure 30. A) Diagram of the OTTLE-IR and cell holder a) back plate, b) teflon gasket, c) salt plate/ minigrid electrode assembly (see Fig 30 B), d) knurled end cap. B) Expanded view of the salt plate/minigrid electrode assembly a) NaCl salt plates, b) Tefzel gaskets, c) gold minigrid electrode, d) indium gasket, e) teflon gasket, f) needle plate. From J. P. Bullock,...

Figure 1 Mini-grid OTTLE cell. (A) Assembly of the cell, (B) front view, (C) dimensions of 100 wires per inch gold minigrid, (a) Point of suction application to change solution, (b) teflon tape spacers, (c) microscope slides (1x3 inches), (d) solution, (e) transparent gold minigrid electrode, (f) reference and auxiliary electrodes, (g) solution cup, (h) epoxy holding cell together. Typical measurements (i) 0.0027 cm, (j) 0.023 cm.

A very thin layer of working solution and the minigrid electrode significantly reduces the diffusion layer and decreases the ohmic-level drop. 

A chopped incident light beam irradiates a gold minigrid electrode, producing radicals in the vicinity of the electrode. The photocurrent for the oxidation or reduction of R can be measured with a lock-in amplifier as a function of potential. For example, the voltammogram for the diphenylmethyl radical generated by photolysis of 1,1,3,3-tetraphenylace-tone in MeCN (0.1 M TRAP) yielded a half-wave potential of —1.14 V vs. SCE for reduction (101). 

Figure 5 shows the first ottle results reported for a biomolecule (i.e., cytochrome These data were acquired by applying potentials to a gold minigrid electrode near the formal potential of cytochrome c and recording each spectrum after achieving redox equilibrium between the electrode, the... 

Encouraged by these results, we have constructed for flow analysis an electroluminescence detector, which utilizes the oxide-covered aluminum and gold minigrid electrodes as the working (light generating) and counter electrodes, respectively. This communication presents a detailed structure of the detector and demonstrates the analytical applicability of the detector on the basis of the experiments carried out by using the 9,10-diphenylanthracene (9,10-DPA)-induced cathodic electroluminescence in the aqueous micellar solution as the model electroluminescent system. 

Fig.l. Electroluminescence detector for flow analysis. (A) quartz window, (B) gold minigrid electrode, (C) oxide-covered aluminum electrode. 

C) microscope slides (1x3 in.), (D) solution, (E) transparent fold minigrid electrode, (F) optical path of spectrometer, (G) reference and auxiliary electrodes, (H) solution cup, and (I) epoxy holding cell together. (Used with permission from J. Chem. Educ., 1976, 53, 594-597 Copyright (c) 1976, Division of Chemical Education, Inc.)... 

In many spectroelectrochemical studies, optically transparent electrodes, which are transparent to radiation in a particular spectral region, have been widely used. One type of transparent electrode consists of a very thin film of conductive material such as platinum, gold, tin oxide, indium oxide, or carbon, which is deposited on a transparent substrate such as glass (visible), quartz (UV-visible), or germanium (IR). A second type of transparent electrode is the minigrid electrode. 

Fig. 1. Optically transparent thin-layer electrochemical cell a) microscope slide b) Teflon tape spacer c) Teflon tube d) solution e) gold minigrid electrode f) optical path of spectrometer g) auxiliary electrode h) reference electrode i) solution cup.

The gold minigrid electrode in the thin-layer cell is first cleaned in nitric acid, acetone, and then in water. Subsequently, the cell is filled with a deaerated 1.0 M HCIO4 solution and the electrode is treated by an oxidation-reduction cycle until the gold electrode is confirmed to be clean by comparison with usual characteristics of a clean gold electrode surface [9]. 

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