Catalytic molecularly imprinted polymer membranes: Development of the biomimetic sensor for phenols detection

Portable biomimetic sensor devices for the express control of phenols content in water were developed. The synthetic binding sites mimicking active site of the enzyme tyrosinase were formed in the structure of free-standing molecularly imprinted polymer membranes. Molecularly imprinted polymer membranes with the catalytic activity were obtained by co-polymerization of the complex Cu (II)–catechol–urocanic acid ethyl ester with (tri)ethyleneglycoldimethacrylate, and oligourethaneacrylate. Addition of the elastic component oligourethaneacrylate provided formation of the highly cross-linked polymer with the catalytic activity in a form of thin, flexible, and mechanically stable membrane. High accessibility of the artificial catalytic sites for the interaction with the analyzed phenol molecules was achieved due to addition of linear polymer (polyethyleneglycol Mw 20,000) to the initial monomer mixture before the polymerization. As a result, typical semi-interpenetrating polymer networks (semi-IPNs) were formed. The cross-linked component of the semi-IPN was represented by the highly cross-linked catalytic molecularly imprinted polymer, while the linear one was represented by polyethyleneglycol Mw 20,000. Extraction of the linear polymer from the fully formed semi-IPN resulted in formation of large pores in the membranes’ structure. Concentration of phenols in the analyzed samples was detected using universal portable device oxymeter with the oxygen electrode in a close contact with the catalytic molecularly imprinted polymer membrane as a transducer. The detection limit of phenols detection using the developed sensor system based on polymers–biomimics with the optimized composition comprised 0.063 mM, while the linear range of the sensor comprised 0.063–1 mM. The working characteristics of the portable sensor devices were investigated. Storage stability of sensor systems at room temperature comprised 12 months (87%). As compared to traditional methods of phenols detection the developed sensor system is characterized by simplicity of operation, compactness, an

Peculiarities of channeling and generated radiation of relativistic electrons in the main charged axes of lithium hydride crystal

The paper deals with the calculation of electron interaction potentials with the main charged [110] axes in a lithium hydride crystal at T = 300, 600, and 900 K temperatures. For relativistic electrons with Lorentz factors γ = 50, 75, 100 the energy and corresponding wave functions of transverse levels of channeling motion are found numerically. The radiation spectra of channeling electrons with (and without) accounting an angular dispersion are calculated on the basis of these data.Проведено розрахунок потенціалів взаємодії електронів із головними зарядженими осями [110] у кристалі гідриду літію за температур T = 300, 600 і 900 K. Для релятивістських електронів із Лоренц-факторами γ = 50, 75, 100 чисельно знайдені енергії та відповідні їм хвильові функції поперечних рівнів канальованого руху. На основі цих даних розраховано спектри випромінювання канальованих електронів за врахуванням (та без врахування) кутової дисперсії.Произведен расчет потенциалов взаимодействия электронов с главными заряженными осями [110] в кристалле гидрида лития при температурах T = 300, 600 и 900 K. Для релятивистских электронов с Лоренц-факторами γ = 50, 75, 100 численно найдены энергии и соответствующие им волновые функции поперечных уровней каналированного движения. На основе этих данных рассчитаны спектры излучения каналируемых электронов с учетом (и без учета) угловой дисперсии

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Abstract-The supramolecular compound cali