Solubility, acid-base and complexation properties of calix[4]resorcinarene in aqueous solutions of nonionic surfactants

Solubility and acid-base properties of calix[4]resorcinarene (H8L) in aqueous solutions of nonionic surfactants Triton X-100, Triton X-405, and Brij-35, as well as isopropanol were studied by pH-potentiometry. The dependence of the amount of a nonionic surfactant necessary to dissolve H8L on the length of ethylene oxide chain was found. The dissociation constants of macrocycle for the first four steps are low sensitive to the medium nature (micellar or water-alcohol solutions). Complexation ability of the [H8-nL]n- anions with respect to tetramethyl- and tetraethylammonium, N-methylpyridinium, and [Co(En)2(C2O4)]+ cations was studied by pH-potentiometry. A noticeable increase in the selectivity of guest-host binding was found on going from aqueous or water-alcohol to micellar solutions

АМПЕРОМЕТРИЧЕСКИЕ ИММУНОСЕНСОРЫ НА ОСНОВЕ УГЛЕРОДНЫХ НАНОМАТЕРИАЛОВ И КЛАСТЕРОВ РЕНИЯ ДЛЯ ОПРЕДЕЛЕНИЯ ТРИЦИКЛИЧЕСКИХ АНТИДЕПРЕССАНТОВ В ПОСЛЕДОВАТЕЛЬНОЙ ИНЖЕКЦИОННОЙ СИСТЕМЕ

A method of sequential injection determination of tricyclic antidepressants (amitriptyline, desipramine, imipramine) using amperometric immunosensors based on screen-printed graphite electrodes modified by carbon nanomaterials (carbon nanotubes, graphene oxide or fullerene) in combination with hexarhenium chalcogenide clusters is proposed. Sequential injection analysis was performed at a sweep rate of 10 mV/s; the flow rate (supporting electrolyte – phosphate buffer solution with pH 7.0) was also varied from 20 to 40 µl/s. Composition of the modifier affects the analytical capability of immunosensors. Screening of various types of modifiers showed that the immunosensor based on graphene oxide and cyanide complexes of rhenium chalcogenide clusters exhibited the highest sensitivity of 23.9±0.9 with a range of working concentrations of 1·10–10–1·10–5 M, and even wider range of detectable concentrations, 1·10–10–1·10–4 M was observed for the immunosensor based on fullerene and cyanide complexes of rhenium chalcogenide clusters. The lowest limit of the determined contents was (4–7)·10–11 M. Relative standard deviation of repeatability (Sr) did not exceed 0.046. The results obtained show that the proposed immunosensors can be used in sequential injection determination of trace amounts of medicinal compounds (antidepressants) in biomedical objects.Keywords: immunosensor, carbon nanomaterials, hexarhenium chalcogenide clusters, tricyclic antidepressants, sequential injection analysisПредложен способ последовательного инжекционного определения трициклических антидепрессантов (амитриптилин, дезипрамин, имипрамин) с использованием амперометрических иммуносенсоров на основе печатных графитовых электродов, модифицированных углеродными наноматериалами (углеродные нанотрубки, оксид графена или фуллерен) в сочетании с гексарениевыми халькогенидными кластерами. Последовательный инжекционный анализ проводили при скорости развертки 10 мВ/с, также варьировали скорость потока (фоновый электролит - фосфатный буферный раствор с рН 7.0) от 20 до 40 мкл/с. Состав модификатора оказывает влияние на аналитические возможности иммуносенсоров. Скрининг различных вариантов модификаторов показал, что наибольшая чувствительность 23.9 ± 0.9 с диапазоном рабочих концентраций 1 ·10-10 – 1 · 10-5 М характерна для иммуносенсора на основе оксида графена и цианидных комплексов халькогенидных кластеров рения, а более широкая область определяемых содержаний 1 · 10-10 – 1 · 10-4 М наблюдается в случае иммуносенсора на основе фуллерена и цианидных комплексов халькогенидных кластеров рения. Нижняя граница определяемых содержаний находится на уровне (4 – 7)·10-11 М.Относительное стандартное отклонение повторяемости (Sr) не более 0.046. Полученные результаты показывают, что предлагаемые иммуносенсоры могут найти применение в последовательном инжекционном определении следовых содержаний лекарственных соединений (антидепрессантов) в медико-биологических объектах.Ключевые слова: иммуносенсор, углеродные наноматериалы, гексарениевые халькогенидные кластеры, трициклические антидепрессанты, последовательный инжекционный анали

COMPLICATED DIAGNOSIS: RETROPERITONEAL ALVEOCOCCOSIS IN THE GUISE OF ORMOND’S DISEASE

Diagnosis of parasitic diseases, in a type of their rarity and diversity, always presents considerable difficulties. Clinical observation of an alveococcosis with invasion in the retroperitoneal space with distribution on mediastinal fat proceeding with progressing retroperitoneal fibrosis with ureteral obstruction and hydronephrosis development, with an aorta lumen stenosis, with formation of SVC syndrome in the absence of changes in other parts of the body, first of all in the liver, in the absence of eosinophilia in the peripheral blood throughout all disease and lack of antibodies to echinococci in the blood serum, twice during observation determined by an immunofermental method is presented in this article

Justification by electrochemical research the use in practice the granular form of cobalt chrome alloy blanks

With the help of electrochemical studies is proved higher corrosion resistance of the cobalt-chromium alloy, produced in the form of pellets, compared with the traditional form of this alloy in bars.С помощью злектрохимического исследования доказана более высокая коррозионная стойкость сплава КХС, выпускаемого в виде гранул, по сравнению с традиционными заготовками данного сплава виде прутков

Synthesis and aggregation properties of new biodegradable amphiphilic derivatives of p-tert-butylphenol for green separation of Gd(III) ions

© 2014 Elsevier B.V. The work introduces a synthesis of novel amphiphilic p-. tert-butylphenol derivatives with the polyethyleneoxide and biodegradable ionogenic polyethylenecarbonate moieties. The dependence of their aggregation behaviour on the lengths of polyethyleneoxide and polyethylenecarbonate chains indicates the impact of the hydrophilic moieties and ionogenic end-groups in the aggregation behaviour of the amphiphiles. The micelles of the amphiphiles are negatively charged, although neither pH nor counter ions (exemplified by Gd(III) ions) affects the values of their critical micelle concentrations. The presence of the ionogenic end-groups is the main reason of the pH and concentration dependent extraction of Gd(III) ions from the neutral (pH 6.2-7.2) aqueous solutions of the amphiphiles through their phase separation at room temperatures. The extraction regularities point on the stoichiometric binding of the amphiphilic molecules with Gd(III) ions as the main reason of the phase separation in their aqueous solutions. Nevertheless the micellization of the amphiphiles is responsible for the peculiar concentration effect on the extraction of Gd(III) ions from the aqueous solutions

Microbial diversity and mineral composition of weathered serpentine rock of the Khalilovsky massif

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Water transverse relaxation rates in aqueous dispersions of superparamagnetic iron oxide nanoclusters with diverse hydrophilic coating

The article introduces transverse relaxation rates of water protons in the aqueous hydrophilic colloids synthesized on the basis of the oleate-coated iron oxide nanoparticles (17. nm) with non-ionic and cationic surfactants, triblock copolymers, polyethyleneimine (PEI) and 4,5-dihydroxybenzene-1,3-disulfoacid disodium salt (Tiron) as hydrophilic components. The IR spectroscopy, atomic force and transmission electron microscopy, along with dynamic light scattering data were obtained to evaluate the content of the hydrophilic coating, the clustering of iron oxide nanoparticles within the hydrophilic covering and the aggregation of hydrophilic nanoclusters. The analysis of the obtained results together with transverse relaxation rates under various concentration, counter-ion and temperature conditions reveals the particular importance of the water molecules diffusion in the outer hydrophilic layer versus the nearest to the iron oxide core layer. The obtained results reveal the counter ion binding with the charged hydrophilic iron oxide colloids as a route to affect the water transverse relaxation rates by biorelevant anionic substrates such as adenosine triphosphates. © 2013 Elsevier B.V

Amperometric immunosensors based on carbon nanomaterials and rhenium clusters for the determination of tricyclic antidepressants in a sequential injection system

Предложен способ последовательного инжекционного определения трициклических антидепрессантов (амитриптилин, дезипрамин, имипрамин) с использованием амперометрических иммуносенсоров на основе печатных графитовых электродов, модифицированных углеродными наноматериалами (углеродные нанотрубки, оксид графена или фуллерен) в сочетании с гексарениевыми халькогенидными кластерами. Последовательный инжекционный анализ проводили при скорости развертки 10 мВ/с, также варьировали скорость потока (фоновый электролит - фосфатный буферный раствор с рН 7.0) от 20 до 40 мкл/с. Состав модификатора оказывает влияние на аналитические возможности иммуносенсоров. Скрининг различных вариантов модификаторов показал, что наибольшая чувствительность 23.9 ± 0.9 с диапазоном рабочих концентраций 1 ·10-10 – 1 · 10-5 М характерна для иммуносенсора на основе оксида графена и цианидных комплексов халькогенидных кластеров рения, а более широкая область определяемых содержаний 1 · 10-10 – 1 · 10-4 М наблюдается в случае иммуносенсора на основе фуллерена и цианидных комплексов халькогенидных кластеров рения. Нижняя граница определяемых содержаний находится на уровне (4 – 7)·10-11 М. Относительное стандартное отклонение повторяемости (Sr) не более 0.046. Полученные результаты показывают, что предлагаемые иммуносенсоры могут найти применение в последовательном инжекционном определении следовых содержаний лекарственных соединений (антидепрессантов) в медико-биологических объектах.A method of sequential injection determination of tricyclic antidepressants (amitriptyline, desipramine, imipramine) using amperometric immunosensors based on screen-printed graphite electrodes modified by carbon nanomaterials (carbon nanotubes, graphene oxide or fullerene) in combination with hexarhenium chalcogenide clusters is proposed. Sequential injection analysis was performed at a sweep rate of 10 mV/s; the flow rate (supporting electrolyte – phosphate buffer solution with pH 7.0) was also varied from 20 to 40 µl/s. Composition of the modifier affects the analytical capability of immunosensors. Screening of various types of modifiers showed that the immunosensor based on graphene oxide and cyanide complexes of rhenium chalcogenide clusters exhibited the highest sensitivity of 23.9±0.9 with a range of working concentrations of 1·10–10–1·10–5 M, and even wider range of detectable concentrations, 1·10–10–1·10–4 M was observed for the immunosensor based on fullerene and cyanide complexes of rhenium chalcogenide clusters. The lowest limit of the determined contents was (4–7)·10–11 M. Relative standard deviation of repeatability (Sr) did not exceed 0.046. The results obtained show that the proposed immunosensors can be used in sequential injection determination of trace amounts of medicinal compounds (antidepressants) in biomedical objects

Solubility, acid-base and complexation properties of calix[4]resorcinarene in aqueous solutions of nonionic surfactants

Solubility and acid-base properties of calix[4]resorcinarene (H8L) in aqueous solutions of nonionic surfactants Triton X-100, Triton X-405, and Brij-35, as well as isopropanol were studied by pH-potentiometry. The dependence of the amount of a nonionic surfactant necessary to dissolve H8L on the length of ethylene oxide chain was found. The dissociation constants of macrocycle for the first four steps are low sensitive to the medium nature (micellar or water-alcohol solutions). Complexation ability of the [H8-nL]n- anions with respect to tetramethyl- and tetraethylammonium, N-methylpyridinium, and [Co(En)2(C2O4)]+ cations was studied by pH-potentiometry. A noticeable increase in the selectivity of guest-host binding was found on going from aqueous or water-alcohol to micellar solutions