Spectrophotometric determination of cadmium(II) with a new thiazolylazo reagent

Abstract

Controlling the content of heavy metals in environmental objects at the level of their maximum permissible concentrations is an important analytical task. The widely used physicochemical methods do not always provide a direct solution to this problem due to the influence of the matrix composition of the sample on the results of determinations, as well as low concentrations of the determined elements. Therefore, targeted synthesis and search for inexpensive and effective technologies for analytical control of heavy toxic metals is still relevant. 1,3-triazole derivatives such as 1-(2-thiazolylazo)-2-naphthol are available compounds. They are produced on an industrial scale. The weak basic and complexing properties of these compounds are due to the presence of a triazole ring in their structure. Extraction is one of the most widespread methods for the isolation and separation of substances and is widely used in technology and analysis. The spectral characteristics of the Cd(II)-1-[5-(4-methylbenzyl)-1,3-thiazol-2-yl)] azonaphthalen-2-ol (MBnTAN) system in toluene were studied for the first time. Optimal interaction conditions for 1-[5-(4-methylbenzyl)-1,3-thiazol-2-yl] azonaphthalen-2-ol with cadmium were established, namely: acidity of the medium (the compound is formed in an alkaline medium at pH = 11.0); the ratio of the components of the complex compound cadmium: reagent is 1:2; maximum light absorption of the Cd-MBnTAN complex at λ = 588 and 610 nm. The effective molar coefficient of light absorption is 1.05∙10 4 l∙mol -1 ∙cm -1 . A sensitive spectrophotometric method for the determination of Cd (II) using MBnTAN with a detection limit of 0.5 μmol/l has been developed and the limits of the linear dependence of the optical density on the concentration of 2.4 to 12.0 μmol/l. The developed method for determining Cd(II) was tested on model solutions. Keywords : сadmium(II), extraction, spectrophotometry, azodyes.