نتایج جستجو برای: liquid nitrogenln
تعداد نتایج: 217784 فیلتر نتایج به سال:
an efficient dispersive liquid-liquid microextraction using tetraalkylammonium bromide coated silver nanoparticles (dllme-agnps) prepared in chloroform has been successfully applied as electrostatic affinity probes to the microextraction and preconcentration of terazosin prior to spectrofluorimetry analysis. this technique is based on a ternary system of solvents, where appropriate amount of mi...
چکیده در بخش اول این پروژه دو روش میکرواستخخرا به نامهای میکرواسخخرا امولسیونی با کمک اموا فراصتتتو 1 و میکرواستتتخخرا مای – مای با کمک هوا 2 ، به عنوان دو روش میکرواستتتخخرا بدون حلال پخشکننده 3 ، برای اسخخرا برخی هیتدروکربتنهای آروماتیتک حلقوی 4 از نمونتههای آبتی بهکار گرفخه و پارامخرهای موثری همچون نوع حلال اسختتتتخرا کننده، حجم حلال اسخخرا کننده، میزان نمک، زمان تابش اموا فراصتو ، تددا...
recently, 6-(2-naphthyl)-2, 3-dihydro-as-triazine-3-thione (ndtt) was synthesized in laboratory and used successfully for the spectrophotometric determination of nanogram levels of cu2+ in aqueous solution. this reagent forms a specific red complex with cu2+ ions after the extraction by chloroform at alkaline ph. the absorption of the complex in the uv region (313 nm) is about 8 times as strong...
a simple and rapid microextraction procedure based on dispersive liquid-liquid microextraction (dllme) was developed for determination and speciation of trace amounts of chromium (cr) by flame atomic absorption spectrometry (faas). in the proposed approach, chloroform and methanol were used as extraction and dispersive solvents. a new schiff's base ligand, bis(2-methoxy benzaldehyde) ethylene d...
phase inversion in liquid-liquid dispersions corresponds to the transitional boundary between oil-in-aqueous dispersion and aqueous-in-oil dispersion. a theoretical model based on simple assumptions was proposed to predict phase inversion point, ambivalence region and the hysteresis effect of inversion. experimental data from the literature were used to validate the model and results were compa...
the effect of magnetic field on the liquid-liquid equilibrium of two ternary systems (water + acetic acid + butyl acetate and water + acetic acid + dimethyl succinate) at 298.15 k under atmospheric pressure was investigated. the results obtained show that the strength of the magnetic field (0.02 t) affects the solubility of acetic acid in the used organic solvents. distribution coefficients and...
the dispersive liquid–liquid microextraction (dllme) method for determination of pb +2 and cd +2 ions in the environmental water samples was combined with inductively coupled plasma-atomic emission spectrometry (icp-aes). ammonium pyrrolidine dithiocarbamate (apdc), chloroform and ethanol were used as chelating agent, extraction solvent and disperser solvent, respectively. some effective parame...
separation of ten sedative- hypnotic drugs was performed by rp-hplc using mixed micellar mobile phase. effect of temperature, type and amount of organic modifier in mobile phase on efficiency (n) and asymmetry factor (b/a) showed that, the appropriate conditions for a good separation were 35°c and 7% (v/v) butanol in mobile phase. variations of selectivity factor versus butanol concentration, ...
امروزه تلاش محققان بر جایگزین کردن داروهای شیمیایی با داروهای مشتق شده از مواد طبیعی به ویژه بر داروهای گیاهی متمرکز شده است زیرا مقاومت عوامل بیماری زا در سطح جهانی و نیز عوارض جانبی داروهای ضدمیکروبی سنتتیک مانند واکنش های آلرژیک گسترش یافته است. در این پروژه اثر ضدباکتریایی عصاره تام متانولی و فراکسیون های گیاه tanacetum fruticulosum ledeb یا مینای بوته ای علیه 6 سوش باکتریایی استافیلوکوکوس...
a second virial coefficient correlation suitable for two different temperatures ranges, (t*)-2£180 and (t*)-2>180, where t* is rt/dhvap is presented. the equation of state can be calculated for different, complicated non-polar, and slightly polar liquid mixtures at any temperature over the range from ttp to tc and up to high pressures. the latent heat of vaporization and density at the triple p...
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