RESUMO
Polycrystalline Zn-Mn-O samples with nominal manganese concentration x = 0.01 and 0.10 were synthesized by a solid state reaction route using (ZnC(2)O(4)·2H(2)O)(1-x) and (MnC(2)O(4)·2H(2)O)(x). Thermal treatment of the samples was carried out in air at temperatures of 673, 773 and 1173 K. The samples were investigated by x-ray diffraction, thermogravimetry, differential thermal analysis, transmission electron microscopy, magnetization measurements and electron paramagnetic resonance. Room temperature ferromagnetism is observed in Zn-Mn-O samples with x = 0.01 thermally treated at low temperatures (673, 773 K). It seems that the ferromagnetic phase could originate from interactions between Mn(2+) ions and acceptor defects incorporated in the ZnO crystal lattice during the thermal treatment of the samples.
RESUMO
The purification of pravastatin, simvastatin and lovastatin in the sodium salt or lactone form and of mevastatin in the lactone form by reversed-phase displacement chromatography is presented. The mobile phases consisted of water or mixtures of water-methanol and water-acetonitrile. Six different displacers were successfully used. Up to 0.14 g of raw sample per gram of stationary phase was loaded on a column packed with silica-based octadecyl phase. Crude substances from 85 to 88% chromatographic purity were purified and at least 99.5% purity was achieved.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Inibidores de Hidroximetilglutaril-CoA Redutases/isolamento & purificação , Lovastatina/análogos & derivados , Lovastatina/isolamento & purificação , Pravastatina/isolamento & purificação , Sinvastatina/isolamento & purificação , Espectrofotometria UltravioletaRESUMO
Ergot alkaloids and their dihydrogenated methanesulphonate (ms) salts were determined and measured in human plasma. High-performance liquid chromatography (HPLC) with fluorometric detection was used for separation of ergot alkaloids in plasma. Several ergot alkaloids and their derivatives, including lysergide (LSD), can be identified in cases of poisoning.
Assuntos
Alcaloides de Claviceps/sangue , Cromatografia Líquida de Alta Pressão , Humanos , CinéticaRESUMO
The new and convenient method for the separation, isolation and characterization of the N-ciano-N'-methyl-N"-(2-/(5-methylimidazol-4-yl)methylthio/ethyl) guanidine and its biotransformation and degradation products was developed. Mass spectra obtained with the FAB (Fast Atom Bombardment) method are described. This method proved to be very successful for the analysis and characterization of studied compounds.
