Dubovyi V. New analytical forms based on Cu(II) complexes with some derivatives of 6,7-dihydroxybenzopyrylium and their application in the analysis

The dissertation is devoted to the study of the conditions of the interaction of Cu(II) with some derivatives of 6,7-dihydroxybenzopyrylium and their extraction for the development of extraction-photometric, in particular microextraction and micellar-extraction methods for the determination of Cu(II) in objects of different nature. Investigates the complexation in the systems "Copper (II) -DOC" and it was found that the interaction of components is accompanied by the batochromic shift of the light absorption band λ = 480 nm, λ = 540 nm and λ = 560 nm for DMDOC, MPhDOC and DPhDOC, respectively. The chemical-analytical characteristics of the interaction products in solutions. It was shown that the introduction of phenyl substituents at positions 2 and 4 of the benzopyrylium cycle of reagents in the transition from DMDOC to DPhDOC leads to an increase in the optimal pH of the interaction, an increase of molar absorption coefficient and reactions contrast, and also leads to the formation of stronger complexes: lgβ are 9.0; 9.4 and 10.1 for complexes with DMDOC, MPhDOC and DPhDOC respectively. The extraction-spectrophotometric method for the determination of Cu(II) in the range of 0.02-0.96 μg/mL using 6,7-dihydroxy-4-methyl-2-phenylbenzopyrylium chloride, which is characterized by high sensitivity (LOD = 0.007 μg/mL) and relative simplicity and has been tested in the analysis of waters of various categories. The conditions of dispersion liquid semi-microextraction for pre-concentration of Cu(II) using 6,7-dihydroxy-2,4-diphenylbenzopyrylium chloride were optimized: pH 5, maximum absorption band 570 nm and mixed extractant containing 1 ml of chloroform and 1 ml of methanol. Under optimal conditions, the calibration graph is linear in the range of Cu(II) concentrations of 4.32–65 μg/L, and the detection limit is 1.29 μg/L. New initiators of micellar extraction at room temperature are proposed. It is shown that sodium (ammonium) salts of aromatic carboxylic acids (benzoic, o-, m- and p-toluic acids) cause the spontaneous formation of the micellar phase of Triton X-100, which is suitable for analytical concentration. The proposed method of micellar extraction concentration of Copper(II) as complexes with chlorides (perchlorates) of 6,7-dihydroxy-4-methyl-2-phenylbenzopyrylium and 6,7-dihydroxy-2,4-diphenylbenzopyrylium was used for further spectrophotometric detection of Copper(II), and the developed techniques were tested in the analysis of water samples. Shows the fundamental possibility of combining chemically-initiated micellar extraction with flame and electrothermal atomic absorption spectroscopy for the first time. It is shown that new analytical forms based on complexes of Copper(II) with derivatives of chloride (perchlorate) of 6,7-dihydroxybenzopyrylium are convenient for development on their basis of combined atomic absorption methods for the determination of microquantities of сopper(II) after their micellar extraction concentration at the room temperature.