DEVELOPMENT OF SENSITIVE ELEMENTS OF OPTICAL SENSORS FOR DETECTION OF ORGANIC AMINES IN CONTAMINATED AREAS

Abstract

Chemical and biological pollutants are present in the presence of gases, so the detection of such gases is necessary for the rapid detection of the presence of pollutants or their components. Organic amines pose a threat to humans and the environment, so the creation of toxic gas sensors is necessary for the rapid detection of these substances. Promising materials for such sensors are conductive conjugated polymers, include polyaniline and their derivatives.The features of the optical absorption of a polyaniline film under the action of ammonia and organic amines were studied. To obtain samples, the method of chemical polymerization of aniline in an aqueous solution of sulfuric acid under the action of an equimolar amount of ammonium persulfate was used.The IR spectrum and optical absorption spectrum of polyaniline were analyzed, and the main characteristic bands of the obtained sample were established. The films were tested for ammonia, diethylenetriamine (DETA), and polyethylenepolyamine (PEPA) vapors. With exposure to ammonia, a significant shift of the band with a peak at λ = 820 nm occurs and a new band with a maximum at λ = 590 nm is formed.Under the action of DETA and PEPA vapors, a decrease in the optical density of the band is observed in the wavelength range of 700–1 000 nm, and in the region of 500–650 nm, optical absorption increases, which may be associated with an increase in the concentration of amino-quinoid fragments. However, under the action of PEPA, the change in the optical density of the band at 820 nm is more noticeable than under DETA, and a band with a maximum at 610 nm is also formed.It was established that the sensitivity of the PAn film to the action of gases is maximum at a wavelength of 600 nm. The reaction rate of samples on ammonia is the highest at λ = 600 nm, and under the action of organic amines – at 820 nm.The results obtained will become the basis for the development of sensitive elements of optical sensors for the detection of toxic amines in contaminated areas, in production facilities of chemical enterprises, warehouses, etc.