Clark-type oxygen electrodes

Amphipol A8-35 was then added and the sample treated as described in 5.1 ("AP-trapped PS2, pH8"). Oxygen evolution was measured with a Clark-type oxygen electrode under continuous, saturating light. 

Fig. 1. Amperometric monitoring of the autoxidation of epigallocatechin gallete in the presence of (A) 0, (B) 2.0, (C) 5.0, (D) 10, (E) 20, and (F) 50 pm CuCl2. The measurements were performed in 0.1 M Tris buffer (pH 9.0) with a Clark type oxygen electrode at 28 °C. The epigallocatechin gallate concentration was fixed at 50 pm. The catechin stock solution was injected into the test solution at t = 0. The inset shows the (initial) steady-state autoxidation rate as a function of Cu2+ concentration. Reprinted from Biochimica et Biophysica Acta, vol. 1569, Mochizuki, M. Yamazaki, S. Kano, K. Ikeda,T., Kinetic analysis and mechanistic aspects of autoxidation of catechins, p. 35, Copyright (2002), with permission from Elsevier Science.

Figure 13.10. Calibration curves for optical sensor and Clark-type oxygen electrode. The phase response of optical sensor and the voltage response of the Clark-type electrode is plotted against percent oxygen in the gas mixture (oxygen and nitrogen) sparged. While the Clark-type electrode shows a linear calibration the optical sensor shows a Siem-Volmer lype relationship (see Section 13.10.2).

Wise, R.R. and Naylor, A.W. 1985. Calibration and use of a Clark-type oxygen electrode from 5° to 45°C. Anal. Biochem. 146 260-264. 

Kwan et al. [27] l-Lactate Yoghurt milk, soda, sport drinks, and healthy supplement Salicylate hydroxylase (SHL), L-lactate dehydrogenase (LDH), and pyruvate oxidase (PyOD)/entrapped by a poly(carbamoyl) sulfonate (PCS) hydrogel on a Teflon membrane Clark-type oxygen electrode ... 

As can be seen in Tables 17.2 and 17.4, a wide variety of different enzymes present in vegetable tissue or in the crude extracts have been immobilized onto Clark-type oxygen electrode membranes or in carbon paste electrodes. To facilitate understanding of the operation of electrode containing PPO or peroxidase in combination with amperometric biosensors a brief discussion is provided below. 

Clark-type oxygen electrode 359 Clenbuterol 68 Clinical 947 Clots 802... 

The enzyme ascorbate oxidase (AOD) is immobilized over Clark-type oxygen electrodes. The biocatalyst is attached to polyamide nets with GA (252), cross-linked with collagen-glutaraldehyde (251) or albumin-GA (253), or linked to cellulose acetate membranes (253). 

Clark-type oxygen electrodes are also available in probe form for immersion in the test solution (Fig. 34.7) e.g. for field studies, allowing direct measurement of oxygen status in situ, in contrast to chemical assays. The main point to note is that the solution must be stirred during measurement, to replenish the oxygen consumed by the electrode ( boundary layer effect). 

Photosynthetic activity of the cells was assessed from measurements of the light saturation curve of photosynthesis, obtained with a Clark-type oxygen electrode as described earlier [Melis et al. 1997]. Actinic excitation was provided in the yellow region of the spectrum by CS 3-69 Coming filter in combination with a 35-5453 VIQ 5-8 Ealing filter. 

Microbial Cell-containing Membranes for Molecular Recognition. Suzuki et al. (87) have proposed a miocrobial sensor which consists of membrane-bound microbial cells and an electrochemical device. The assemblies of microbial sensors are similar to enzyme sensors. Two types of microbial sensors have been developed as presented In Figure 9. The first monitors the respiration activity of membrane-bound microbial cells with a Clark-type oxygen electrode. The... 

The above measuring principle has been modified for the measurement of HRP substrates which are themselves electrochemically active. To avoid electrochemical interference a Clark-type oxygen probe was used together with catalase coimmobilized with GOD. The hydrogen peroxide not consumed by HRP is cleaved by catalase to oxygen which is indicated at the electrode. Consequently, the biochemical basis of the sensor is the competition of HRP and catalase for the common substrate, H202. 

Sidwell and Rechnitz (1985) placed a slice of banana pulp tissue on the gas-permeable membrane of a Clark-type oxygen electrode. The banana tissue contains polyphenol oxidase which catalyzes the oxidation of dopamine to dopamine quinone and further to melanin at the expense of oxygen. Wang and Lin (1988) integrated this biocatalytic phase in the electrode body of a membrane-free carbon paste electrode and measured the formation of dopamine quinone at a potential of -0.2 V. This arrangement permitted selective determination of dopamine in the presence of ascorbic acid with a response time of only 12 s. It seems likely that this improved performance of a tissue-containing sensor could be extended to other analytes. 

However, these reports of multitudinous enzyme-based biosensors should be viewed with some caution, as it is much easier to demonstrate the possibility of using an enzyme in a laboratory prototype than to convert these observations into a reliable, and reproducible, device that can meet commercial product requirements. This is illustrated by table 7.1, which lists the few enzymes that have been reported to have been used in commercial biosensors only about two dozen enzymes have been used commercially. Most of the enzymes are oxidases partly because of the stability of this class of enzyme, and partly because of ease of linking this type of enzyme with a Clark-type oxygen electrode. 

The measurement of oxygen evolution using a Clark-type oxygen electrode is a standard procedure in the field of photosynthesis research. The measure is simple and the oxygen electrode constitutes an interesting method to evaluate the photosynthetic activity. Several types of photosystem II specific artificial electron acceptors can be used as electroactive mediators to maximize the photosynthetic activity. The more used mediator is potassium ferricyanide " but this one... 

Divakaruni AS, Rogers GW, Murphy AN (2014) Measuring mitochondrial function in permeabilized cells using the Seahorse XF analyzer or a Clark-type oxygen electrode. Curr Protoc Toxicol 60, 25.2.1-16. 

Photosystem II preparations were made from fresh market spinach according to (6,7) and polypeptide depleted as in (4). Oxygen evolution activity was assayed in a Clark-type oxygen electrode using 2,6-dichloro-p-benzo-quinone as the electron accepter. Tetramethylammonium chloride was used for the addition of Cl , and Ca(0H)2 neutralized with MES was used for Ca" addition. 

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