Liquid electrodes

Through static electrodes liquid electrolyte or chemical resistance starting... 

Koval CA, Howard JN (1992) Electron transfer at semiconductor electrode-liquid electrolyte interfaces. Chem Rev 92 411 33... 

When a constant ionic strength of the test solution is maintained and the reference electrode liquid bridge is filled with a solution of a salt whose cation and anion have similar mobilities (for example solutions of KCl, KNO3 and NH4NO3), the liquid-junction potential is reasonably constant (cf. p. 24-5). However, problems may be encountered in measurements on suspensions (for example in blood or in soil extracts). The potential difference measured in the suspension may be very different from that obtained in the supernatant or in the filtrate. This phenomenon is called the suspension (Pallmann) effect [110] The appearance of the Pallmann effect depends on the position of the reference electrode, but not on that of ISE [65] (i.e. there is a difference between the potentials obtained with the reference electrode in the suspension and in the supernatant). This effect has not been satisfactorily explained it may be caused by the formation of an anomalous liquid-junction or Donnan potential. It... 

Polarizer layer Glass plate Electrode Liquid crystal Electrode Glass plate Polarizer layer Mirrored surface/... 

They are classified by membrane material into glass membrane electrodes, crystalline (or solid-state) membrane electrodes, and liquid membrane electrodes. Liquid membrane electrodes are further classified into liquid ion-exchange membrane electrodes and neutral carrier-based liquid membrane electrodes. Some examples are shown in Fig. 5.36 and Table 5.3. If the membrane is sensitive to ion i of charge Z and the activities of i in the sample and internal solutions are equal to (i) and a2(i), respectively, the membrane potential, m, which is developed across the membrane, is... 

Panel (c) shows typical results for the pH of rainwater. The average of the 17 measurements is given by the horizontal line at pH 4.14 and the letters s, t, u, v, w, x, y, and z identify types of pH electrodes. Types s and w had relatively large systematic errors. The type s electrode was a combination electrode (Figure 15-9) containing a reference electrode liquid junction with an exceptionally large area. Electrode type w had a reference electrode filled with a gel. 

Fadner (42) reported preliminary results of electrically initiated polymerization experiments where liquid vinyl monomers are isolated from the electrodes. Liquid ethyl acrylate, for example, absorbed on a filter paper was polymerized in an alternating electric field. The filter paper was sandwiched between two layers of 1.5-mil Mylar film and placed between flat, parallel aluminum electrodes. Conversions of monomer to polymer ranged from 10 to 85% in the range between 20 and 240 sec at up to 25 kcps power. Acrylic acid and its ester polymerized most readily, others, such as styrene and vinyl chloride, resulted only in low yields in the same condition. 

A dual-electrode liquid chromatography-electrochemistry (LCEC) system used in the detection and identification of flavanols and procyanidins in wines and grape seeds is a valuable tool (30). Voltammetric behavior of phenolic compounds by LCEC could provide information that cannot be obtained using HPLC with UV detection, for which the identification is usually based on a comparison of the retention time with that of standard compounds, especially for the identification of catechins and procyanidins with a small amount of sample available (30). Figure 10 shows the procyanidins commonly found in wines. 

SM Lunte, KD Blankenship, SA Read. Detection and identification of procyanidins and flavanols in wine by dual-electrode liquid chromatography-electrochemistry. Analyst 113 99-102, 1988. 

An electrochemical reaction can be defined as a chemical reaction involving charge transfer through an interface. The most commonly known form of charge transfer is the transfer of electrons over a solid electrode-liquid electrolyte interface. In the simplest form, electrons can be transferred from the electrode to a chemical substance in solution (reduction), or electrons that were released from the chemical substance by oxidation can be taken up by the electrode. This is generally given by Equation 1.1 ... 

Polarizer J Glass substrate Electrode Liquid crystal... 

Variation of Reference Electrode Potentials with Temperature pH Values of Standard Solutions Used in the Calibration of Glass Electrodes Temperature vs. pH Correlation of Standard Solutions Used for the Calibration of Electrodes Solid Membrane Electrodes Liquid Membrane Electrodes... 

In contrast to solid-membrane electrodes, liquid-membrane electrodes can extract counterions from the solution-phase into the membrane phase. Selectivity is provided by the charged nature of the membrane carriers and arises from the competitive degree of extractability of various counterions. Totally liquid systems can be employed but are impractical. Instead, a porous support or an inert polymer support is used in most commercial electrodes. 

A significant number of studies have characterized the physical properties of eutectic-based ionic liquids but these have tended to focus on bulk properties such as viscosity, conductivity, density and phase behavior. These are all covered in Chapter 2.3. Some data are now emerging on speciation but little information is available on local properties such as double layer structure or adsorption. Deposition mechanisms are also relatively rare as are studies on diffusion. Hence the differences between metal deposition in aqueous and ionic liquids are difficult to analyse because of our lack of understanding about processes occurring close to the electrode/liquid interface. 

L. A. Allison and R. E. Shoup, Dual-electrode liquid chromatography detector for thiols and disulfides, Anal. Chem. 55, 8-12 (1983)... 

Fuel cell researchers deal primarily with interfaces between solid electrolyte materials and solid metallic electrodes. The characterization of electrochemical systems with solid-solid interfaces has become a major issue in the study of fuel cells. It is generally believed that the interface of a solid electrode and solid electrolyte is similar to the electrode/liquid electrolyte interface but more complicated [4],... 

From Eqs. (73) and (74) which describe accumulation and depletion for strong effects, the concentrations of the other mobile species are simply accessible through Eq. (68). In liquid electrochemistry these profiles have been used to evaluate electrode/liquid electrolyte capacitances.79... 

While there have been many SHG studies at the solid electrode/liquid interface as both an in situ probe of the electrode interface and the influence of adsorption at the surface of the electrode, there have been far fewer studies of electrochenucal processes occurring at the boundary between two immiscible electrolyte solutions. 

Lunte, C.E. Kissinger, P.T. Investigation of 6-methyl-pterin electrochemistry by dual-electrode liquid chromato-graphy/electrochemistry. Anal. Chem. 1984, 56, 658-663. 

Ding, X.D. Krull, I.S. Dual electrode liquid chromatography-electrochemical detection (LCEC) for platinum-derived cancer chemotherapy agents. J. Liq. Chromatogr. 1983, 6, 2173-2194. 

Payne RB, Jones DP. Protein interferes with ionized calcium measurement at the reference electrode liquid junction, Ann Chn Biochem 1987 24 400-7. 

KCl In order to preclude KCIO precipitates at the reference electrodes liquid junctions. The use of two Corning model 130 pH meters permitted simultaneous measurement of pH and free copper concentrations. Electrode calibrations demonstrated a Nernstlan response (within IZ of theoretical) for both pH and copper electrodes. Free ligand concentrations were varied by titrating our... 

Gao Y. Q., Georgievskii Y. and Marcus R. A. (2000), On the theory of electron transfer reactions at semiconductor electrode/liquid interfaces , J. Chem. Phys. 112, 3358-3369. 

Koval, C. A., Howard, J. N., Electron transfer at Semiconductor Electrode Liquid Electrolyte Interfaces, Chem. Rev. 1992, 92, 411 433. 

In a typical facilitated IT reaction an ion (most often, a cation, M+) is transferred from aqueous solution into the organic phase. A complex species formed by this ion and a ligand (L, initially present in organic phase) is easier to transfer than M+ itself. Reactions of this type are widely used in chemical sensors [ion-selective electrodes, liquid ion-exchangers (50)]. For SECM experiments, an aqueous solution of M+ is placed inside a micropipet, which serves as a tip electrode. The facilitated IT reaction at the micropipet tip is... 

We also measured the capacity of a reference electrode-liquid surface system with a Wayne-Kerr Universal bridge. The capacitor was formed between a large aluminum plate (20 cm diameter) which slightly overlapped a hydrophobed dish (18 cm diameter) which held an electrolyte solution. The measuring circuits included a potentiometer to dc bias the electrode system. 

A method for determining the pH of much smaller samples was developed by Lloyd Claff and Swenson (L6). They considered the sealed-in capillary a disadvantage and consequently used loose capillaries (of 5-pl capacity). After filling these were brought in contact with electrode liquids in a special container. 

Liquid level of outer reference electrode Liquid level of inner reference electrode... 

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