LED optrode for detecting sulfur dioxide in air

Abstract

Scheme of an LED optrode for detecting sulfur dioxide in the air is considered. The components of the device are (1) a glass plate coated with a copolymer film of n-decylmethacrylate and styrene sulfonate with ion-coupled cation of the brilliant green dye, (2) an LED emitting at a wavelength of 655 nm, and (3) a metal housing. The nominal static conversion function of the device and its sensitivity are analyzed on the basis of mathematical modeling. It is established that the maximum sensitivity in determining the sulfur dioxide concentration in the air is achieved in the case in which the glass plate of the optrode is covered with a polymer film characterized by a specific value of the optical density in pure air containing no sulfur dioxide. For example, for a sulfur dioxide concentration close to zero, the film optical density should be close to one. The presented results allow one to make an optrode suitable for ensuring environmental and sanitaryhygienic safety. The device provides the ability to create analyzers for the measurement of sulfur dioxide in air that have small overall dimensions, power consumption, and cost.