Gold minigrid electrode

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). 

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 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. 

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]. 

Fig. 9. Experimental setup for impedance measurements with electrochenucal control of membrane impedance platinized platinum electrodes (a) constant voltage power supply, (b) gold minigrid electrode (c) polypyrrole film, (d) 1 M KCl solution (e) constant current ac circuit, (f). At right is a microscopic view of membrane, illustrating effect of membrane potential on ionic resistance (reprinted with permission ft om Ref.

Figure 1 Cyclic voltammograms at a surface-modified gold minigrid electrode ( — ) 0.30 M spinach ferredoxin in 0.1 M Tris, 0.1 M NaCl, pH 7.0 ( — ) same electrode after rinsing cell and introducing buffer alone. Scan rate 5 mV/s.

Edmund E. Bowden conducted potential step chronoabsorptometry experiments on the reaction of myoglobin at modified gold minigrid electrodes [40]. Although these experiments were very reproducible, the heterogeneous electron transfer kinetic parameters raised concerns, namely, the rate constant was very low (k° = 3.9 X 10-11 cm/s) and alpha was high (a = 0.88). These issues became muted as the work progressed, as will be discussed below. 

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