Light Emission Diode Water Thermometer: A Low-Cost and Noninvasive Strategy for Monitoring Temperature in Aqueous Solutions

A spectroscopic device for monitoring the temperature of aqueous solutions is presented. It uses a 950 nm light emission diode as light source and two photodiodes as detectors. Temperature is monitored following the thermally induced absorbance changes of the water-OH second overtone (∼960 nm). A li...

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Detalles Bibliográficos
Autores principales: Thompson, S.A., Andrade, F.J., Iñón, F.A.
Formato: JOUR
Materias:
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00037028_v58_n3_p344_Thompson
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Descripción
Sumario:A spectroscopic device for monitoring the temperature of aqueous solutions is presented. It uses a 950 nm light emission diode as light source and two photodiodes as detectors. Temperature is monitored following the thermally induced absorbance changes of the water-OH second overtone (∼960 nm). A linear response between the light absorbed by an aqueous solution and its temperature is found in the range from 15 to 95 °C. A prediction error of 0.1 °C and a precision of 0.07 °C in temperature measurement can be achieved. Up to 0.1 M of electrolyte concentration can be present in the solution without significantly affecting the temperature measurement. Different strategies, such as remote (noninvasive) or in situ (using a fiber-optic probe) temperature measurement, are shown, and their relative advantages are discussed.