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Chemical engineering is an engineering branch that deals with the chemical production and manufacture of products that undergo chemical processes. This includes equipment design, creating systems and processes to refine raw material, as well as mixing, compounding, and processing chemicals to create products.

Chemistry and Chemical Engineering

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Complexes of hydroxy- and alkyloxytetraphenylporphyrins with Cu (II), Zn (II), and Ni (II) have been prepared and their chromatographic behavior in adsorption and partition thin-layer chromatography has been investigated. Gutman topological indexes, Mν, and the screening effect, SE, of the hydrocarbon chains on the electron pairs of the oxygen atoms of –OR groups have been calculated for the metalloporphyrin derivatives studied. The correlation between these and chromatographic retention, expressed as RM values, has been studied.

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Planar electrochromatography (PEC) is a mode of planar chromatography in which the mobile phase is driven by electroosmotic flow. The variables that affect the performance of PEC with an aqueous mobile phase on a bonded octadecylsilyl layer are discussed. These include the magnitude of the applied electric field, the concentration of the buffer salt, the pH of the mobile phase, and the concentration of acetonitrile used as the organic modifier. The effect of changing each of these variables is illustrated by model separations of a mixture of four compounds of diverse structure.

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Planar chromatographic methods thin-layer chromatography (TLC) and over-pressure thin-layer chromatography (OPLC) have been developed for the determination of pigments in plant leaves. Plants with variegated leaves, which sometimes contain both anthocyanins and chlorophyll, are a reasonable material for investigation. Multicolored Coleus, Prunus cerasifera, and Rhus hirta leaves were taken for quantitative determination of anthocyanins and chlorophyll. The separation of pigments from plant leaves, which depends on compound polarity was optimized by appropriate selection of mobile and stationary phases and chromatographic conditions.

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The chromatographic behavior of fullerene C60 has been studied on silica gel layers impregnated with solutions of glucose, sucrose, fructose, and dextrans of MW 20, 40, and 110 kDa, and with hexane as mobile phase. It was found that the RF of fullerene decreases as the concentration of impregnating solution is increased. The retention of fullerene C60 changes to a smaller extent when dextran solutions are used.

The solid-phase interaction of fullerene with the carbohydrates sucrose and dextran was studied by use of differential scanning calorimetry (DSC) and by NMR and UV-vis spectroscopy. The interaction with sucrose is greater than that with the dextrans.

Correlation was observed between the chromatographic behavior of C60 fullerene and the solid-phase interaction of the compound with carbohydrates.

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Carbohydrates have been examined by TLC on layers modified with metal ions, in the form of salts, by dipping commercial plates in methanolic solutions or by use of mobile phase additives; the mobile phases were mixtures of acetonitrile, propan-2-ol, or acetone with water or aqueous solutions of the metal salts. The effect on spot shape and retention of the identities and concentrations of the metal ions used for impregnation are discussed, and the selectivity of the different systems investigated are compared. The chromatographic properties of the adsorbents used were compared by consideration of the relationships between RM values measured on the different layers.

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In normal TLC practice, migration of the mobile phase through the layer is controlled by capillary forces. Under these conditions the velocity at which the solvent front moves is a function of the distance of the front from the solvent entry position, and this velocity declines as the distance increases. In this work we have proved that the velocity and migration distance of the mobile-phase front in porous media can be increased by application of an external electric field. We have called this displacement effect on liquids ‘dielectroosmotic flow’ (DEOF), because of its similarity with electrokinetic phenomena. Capillary tubes were used to enable understanding of the flow phenomena which occur in porous media.

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A stand-alone argentation TLC (Ag-TLC) procedure has been established for rapid estimation of the authenticity and densitometric quantitation of fatty acid groups in milk fats. The applicability of methyl (ME) and isopropyl (IPE) ester derivatives for accurate short-chain fatty acid analysis by Ag-TLC and GLC was compared and a correction coefficient compensating for loss of C4–C10 saturated fatty acids has been proposed. To check its accuracy and reproducibility the method was applied to model mixtures and to real margarine and butter samples. Low levels of trans fatty acids can be unequivocally detected and amounts down to 0.2% can be measured precisely. The method gives a good estimate of the diversity of isomeric fatty acids in the samples and when precautions are taken to avoid overloading, it provides reliable results with good accuracy.

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