Environmental oxygen sensors

Doped zirconium dioxide is the solid electrolyte in lambda sensors (oxygen sensors used in the field of environmental protection). 

A variety of optical oxygen sensor systems have been developed for applications such as biomedical, environmental and process control . But very few of them have been critically assessed for their suitability for food packaging applications. It has been proven that substantial development, optimization and redesign of the oxygen-sensitive materials and fabrication processes are required for the oxygen sensors to match practical requirements for these applications5. In particular, specific requirements of food applications are ... 

Hecht, H. K611ing, M. (accepted) Investigation of pyrite weathering processes in the vadose zone using optical oxygen sensors. Environmental Geology. 

Koeneke, R., Comte, A., Juergens, H., Kohls, O., Lam, H., and Scheper, T. (1999), Fiber optic oxygen sensors for use in biotechnology, environmental, and food industries, Chemical Engineering and Technology, 22(8) 666-671. 

Figure 6.14. Fluorescence sensor deployment platforms. (A) CTD Rosette vertical profiler. Water was pumped in series through a fluorometer and other environmental sensors, where instruments were mounted at the bottom of the Rosette and CDOM fluorometer. (Courtesy of R. Conmy.) (B) Towed vehicle with various optical and chemical sensors. (Courtesy of R.F. Chen.) (C) Minishuttle tow-yo vehicle deployed with chlorophyll and NOM fluorometers, dissolved oxygen sensor, and CTD. (Courtesy of R.F. Chen.) (D, E) Buoys, moorings, and gliders are also platforms for optical and environmental sensors. (Courtesy of Cefas.) (See Plate 10.)...

An environmentally friendly sensor was developed by fabricating a nickel-copper (NiCu) alloy electrode to determine the chemical oxygen demand. The NiCu alloy film was applied to modify the surface of a glassy carbon electrode which led to a very stable detecting element. The surface morphology of NiCu alloy was investigated by atomic force microscopy which confirmed its continuity and uniform thickness over the entire electrode. The chemical composition of the developed NiCu film was evaluated by energy-dispersive X-ray spectrometry which revealed 69 % presence of Ni in the alloy. 

Leland C. Clark developed this well-known oxygen sensor in 1956 which is widely used for physiological, industrial, and environmental analysis. It is an amperomet-ric sensor which consists of a working electrode, a reference electrode, and the electrolyte as shown in Fig. 3.1. 

The model analytes, which were used to show the sensor performance of the microsystems include carbon monoxide, CO, and methane, CH4. The sensor microsystems were designed for practical applications, such as environmental monitoring, industrial safety applications or household surveillance, which implies that oxygen and water vapors are present under normal operating conditions. In the following, a brief overview of the relevant gas sensor mechanisms focused on nano crystalline tin-oxide thick-film layers will be given. 

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