The chromatographic behaviour of liquid crystalline compounds benzylidene-p-aminobenzoic acid and 4-(p-methyl benzylidene)-p-aminobenzoic acid as stationary phases for the separation of dimethylphenol isomers was investigated. These isomers were analysed on benzylidene-p-aminobenzoic acid within a nematic range of 169-194 ◦C with a temperature interval of 5 ◦C. Better peak resolution was at a column temperature of 190 ◦C. The analysis was repeated on a 4-(p-methyl benzylidene)-p-aminobenzoic acid column at a nematic temperature of 256 ◦C, which represented the end of the nematic range, and gave the optimum peak resolution. It was found that isomer better separation was obtained at 20% loading for both liquid crystal materials. Other columns of different liquid crystalline percentages (15% and 25%) were used. A chromatogram with unoverlapped peaks was only obtained in both cases at 20% column loading. The order of elution isomers under the applied chromatographic conditions is discussed. The separation of these isomers is also discussed on the basis of stereo chemical confirmations.
The Synthesis C!}f a; rw;v Schiff base ligan-d .N ' N - bis(2> 4,6-
trjpr;diOXY meth)l) benz1dine l 6L] aAd its c.omplexes w.ith· Co 1ll 1 , Ni('ll);
cu< I·> Zn(ll) .and Cd(TJJ are reported . The ltgand was prepared by the
reaction of 4,4-aniino-biphenyl benzidine with 2,4;6· tnliydro yace ophenon mQnohydmte ander reflux in m tbaool as solvent and a few d
... Show MoreBackground: five clinical phases were described in patients with chronic (HBV) infection: HBeAg- positive HBV infection, HBeAg- positive chronic HB, HBeAg negative HBV infection, HBeAg-negative CHB and occult HBV infection. Aim: This study aimed to determine the incidence of the unclassified phase (gray zone) in chronic hepatitis B patients and its significant in the clinical practice. Patients and methods: The study was conducted retrospectively on 109 patients' who have HBsAg positive for more than 6 months. The data recorded include; HbeAg and anti-HBe Ab, ultrasound of the abdomen, HBV DNA load and alanine aminotransferase (ALT), accordingly; we classify the patients to known clinical phases. Patients who were unfit one of these phases
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The study focused on the treatment of real oilfield produced water from the East Baghdad field affiliated to the Midland Oil Company (Iraq) using an oil skimming process followed by a coagulation/flocculation process for zero liquid discharge system applications. Belt type oil skimmer was utilized for evaluating the process efficiency with various operating conditions such as temperature (17-40 °C) and time (0.5-2.5 hr.). Polyaluminum chloride (PAC) coagulant and polyacrylamide (PAM) flocculant was used to investigate the performance of the coagulation/flocculation process with PAC dosage (5-90 ppm) and pH (5-10) as operating conditions. In the skimming process, the oil content, COD, turbidity, and TSS decreased with an increase in tempera
... Show MoreResumen
El trabajo se investiga en el realismo y la tradición social que incluye la tragedia Bodas de sangre, del autor español Federico García Lorca. A lo largo de estas páginas se da la luz sobre los temas, acciones, oraciones y palabras que pertenecen a la realidad de la vida española en general y sobre todo en territorio andaluz, en el que ocurren los sucesos de la obra. Así como las tradiciones sociales que el dramaturgo español contemporáneo abundando a lo largo de su texto, y que han sido tomadas de la herencia popular.
Literariamente, esta obra se clasifica como Tragedia Moderna, por la razón de que incorpora los elementos necesarios de d
... Show MoreEl tema de esta investigación está directamente relacionado con el papel del léxico en la enseñanza-aprendizaje del español como segunda lengua en el sistema de enseñanza universitariairaquí, donde se llevó a cabo la investigación empírica y la propuesta de criterios de la selección de léxico español.
Este estudio se ha centrado concretamente en los alumnos irakíes de nivel elemental que estudian elespañol como segunda lengua extranjera. Con el fin de conocer los estilos de enseñanza-aprendizaje del vocabulario practicado en las aulas, de determinar las faltas en la selección léxica y realizar propuestas de mejorar la competencia léxica, hemos efectuado el an
... Show MoreThe weight of larvae virgins and Alcamlat for males more than the weight of females of the roles themselves that the highest rate of loss in weight of larvae developed to virgins when field conditions were (21.5,22,21.3) mg during June and July and August respectively, recorded the highest degrees of heat and less attributed to moisture
Amino glycoside derivation including, Neomycin, Streptomycin, Kanamycin and Gentamycin with special reagents, which are benzoylchloride; benzene sulfonyl chloride and phthalic anhydride were made to enhance Uv-detectability for HPLC analysis. But there are many problems facing pre column derivation and in order to solve this, the conductivity of antibiotic derivatives were used to calculate the dissociation constant and the hydrolysis rate which determined concern type reaction. In addition the characteristics those controlling the hydrolysis of antibiotic-derivatives were investigated.
The development of a reversed phase high performance liquid chromatography fluorescence method for the determination of the mycotoxins fumonisin B1 and fumonisin B2 by using silica-based monolithic column is described. The samples were first extracted using acetonitrile:water (50:50, v/v) and purified by using a C18 solid phase extraction-based clean-up column. Then, pre-column derivatization for the analyte using ortho-phthaldialdehyde in the presence of 2-mercaptoethanol was carried out. The developed method involved optimization of mobile phase composition using methanol and phosphate buffer, injection volume, temperature and flow rate. The liquid chromatographic separation was performed using a reversed phase Chromolith® RP-18e column
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