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Abstract. The effect of intermolecular interactions on processes of micelle formation and adsorption in binary mixtures of non-ionic Triton X100 (TX100) with ionic sodium dodecyl sulfate and dodecylpyridinium bromide surfactants was studied. The ionic surfactants have identical hydrophobic alkyl chain and different hydrophilic groups. A feature of the used binary surfactant mixtures is that critical micelle concentrations and surface activity of the individual components are considerably different. A synergetic effect of decreasing of the surface tension was found in the surfactant mixtures. It was shown that the mixed adsorption layers and the micellar phases are enriched with the nonionic surfactant. For both sodium dodecyl sulfate/TX100 and dodecylpyridinium bromide/TX100 systems, the synergetic effects were most pronounced at a high molar fraction of the nonionic surfactants in the mixture. By using the Ruben-Rosen model, molecular interaction parameters in the mixed micelles βm, and in the adsorption layers βσ were evaluated. As was shown βm and βσ parameters to be notably higher for sodium dodecyl sulfate/TX100 mixture. Resumen. Se estudia el efecto de las interacciones intermoleculares en el proceso de formación y adsorción de micelas en mezclas binarias de Triton X100 (TX100), no iónico, con dodecil sufato de sodio y bromuro de dodecil piridinio, ambos iónicos, como surfactantes. Los surfactantes iónicos tienen cadenas alquílicas hidrofóbicas idénticas y grupos hidrofílicos diferentes. Una característica de las mezclas binarias de surfactantes que se utilizaron es que las concentraciones micelares críticas y la actividad superficial de los componentes individuales es considerablemente diferente. Se encontró un efecto sinérgico de decremento de la tensión superficial en las mezclas de surfactantes. Se muestra que las capas mixtas de adsorción y las fases micelares están enriquecidas con surfactante no iónico. Tanto en el sistema dodecil sufato de sodio/TX100 como en el caso de bromuro de dodecil piridinio/TX100, los efectos sinérgicos fueron más pronunciados en las mezclas con fracciones molares altas de los surfactantes no iónicos. Utilizando el modelo de Ruben-Rosen, se evaluaron los parámetros de interacción molecular en las micelas mezcladas βm y en las capas de adsorción βσ. Se muestra que los parámteros βm son βσ son notablemente mayores en la mezcla de dodecil sufato de sodio/TX100.

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The measurement of xenobiotics (polycyclic aromatic hydrocarbons (PAHs) group) in agricultural objects: soil, water, plant products was developed and tested by the high performance liquid chromatography method in this work. Our investigation was carried out by using laboratory samples taken from the research farm "Snitynka". Optimal modes of high-performance liquid chromatography method with a fluorescent detector (HPLC/FLD) were established for xenobiotics measurement: benzo(a)anthracene, benzo(a)pyrene, benzo(e)pyrene, benzo(b)fluorine, chrysene and their mixtures. Metrological characteristics of PAHs measuring were established: the limit of quantitative analysis (LOQ = 1.0 μg/kg), the limit of detection (LOD = 0.25 μg/kg), measuring range 1.0 - 10.0 μg/kg, the total measurement error (%) for each xenobiotics content average did not exceed 20%. The approbation of the methodology was performed in series of 50 model samples in the concentration range of each xenobiotics from 1.0±0.1 μg/kg to 10.0±0.1 μg/kg and in series of 50 natural samples. It is established that the developed method allows to unify laboratory control of PAHs and improves the process of monitoring analysis of xenobiotics.