The interaction of 5 anionic xanthene dyes -9-R-2,3,7-trihydroxy-6-fluorones (ТОF) with cationic polyelectrolyte (PE) -polyhexamethyleneguanidine chloride (PHMG) has been studied by the optical spectroscopy in a concentration range where PHMG has a polyelectrolyte effect. Hammet σ-constants were calculated. The correlations between structure of ТОF and shift of protolytic equilibrium in aqueous-polyelectrolyte solutions were established. Influence of рН, concentration of the ethanol, components ratio in the system PHMG-TOF on the character of the interaction of cationic PE with ТОF and value of the analytical signal were studied based on absorption spectra. The results were compared to those obtained in water solutions.Keywords: trioxyfluorone; spectrophotometry; polyhexamethyleneguanidine chloride; polyelectrolyte; ionisation constant; aggregation.Introduction. The application of dyes is frequently connected with the definition of PE [1][2][3][4][5][6][7]. 9-R-2,3,7-Triohydroxy-6-fluorones are the most widely studied and used. The degree of PE influence on ionic equilibriums in the dye solutions depends on numerous factors involved in the process of PE-dye interaction. The effect is caused by capability of PE to change property of the substances in solubilized condition that is connected with the change of medium properties in a microenvironment [8; 9]. The solubilized substance passes from aqueous to aqueous-polyelectrolyte microphase. Thus the competitive interactions between polymeric molecules and dye, solvent and components of the system are possible. The number of trapped ions of dye depends on the number and conformation of PE molecules in the solution [10; 13]. The formation of assosiates «PE-dye» is possible by means of a hydrogen bridging, electrostatic and hydrophobic interactions and depends on the concentration ratio of the components. The change of chemical-analytical properties of dyes in the presence of PE was described earlier: phenylfluorone with a nonionic PE poly(vinylpirrolidone) [11], bromphenol red and chlorphenol red with PHMG [8; 9]. The purpose of the present work is to study the optical, protolytic properties, as well as specifics of associate formation between ТОF with various substituents in 9 position of xanthene core and cationic PE -PHMG (М r ≈1,0×10 4 and 6,4×10 3 ) in aqueous and aqueous-alcoholic solutions. Experimental Materials and methods. Structural formulae of ТОF ( fig. 1) are shown in a table 1. Starting solutions of PhF and SF C = 1×10 -3 mol/L were prepared on the day of the experiment by dissolving the sample in 25 ml of twice-distilled water with addition of several drops of concentrated NaOH solution. Initial alcoholic solutions of o-NPhF, DSPhF and NF were prepared according to recommendations [12]: 1 ml HCl (6 mol/L) and 80-85 ml of 96% ethanol were added to the sample of dye and carefully heated until
The interaction of two trioxyfluorone dyes disulfophenylfluorone and nitrophenylfluorone with Mo(VI) and polyhexamethyleneguanidine (PHMG) in the presense of NO 3-ions has been studied by optical spectroscopy. This ternary analytical system was proposed for determination of PHMG. Compositions of ternary complexes, formed in the system, were confirmed by the ternary Gibbs-Rosenbaum diagram. The optimal components ratio in complexes NPF:PHMG:Mo(VI) is 3:1:1 (at 520 nm) and 6:3:1 (at 570 nm). The associate PHMG:NPF with ratio 1:2 and macrometalchelate PHMG•2Mo(VI) also records. The metals such as Cu(II), V(IV), W(VI), Al(III), Co(II) do not interfere with the determination. Proposed technique allows to determine PHMG on second order nonlinear calibration curves in the concentration range of 0.1-2.0 mg/L. The limit of detection is 0.03 mg/L. Statistical treatment was carried out in ac
Изучено влияние катионных флокулянтов марки FO на спектральные и протолитические характеристики бромфенолового синего. Показано, что в присутствии полимеров проявляется два типа эффектов: смещение кислотно-основного равновесия и агрегирование красителя. Установлены оптимальные условия образования ионного ассоциата. Присутствие неорганических солей частично разрушает ионный ассоциат. До определенной концентрации мешающее влияние можно устранить, используя метод фотометрического титрования. Разработаны спектрофотометрические методики определения КПАА FO методами градуировочного графика в интервале концентраций полимера 0,12-1,8 мг/л и фотометрического титрования. Методики апробированы на искусственных смесях и артезианской воде.
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