Complexation of the Fe(III) and Fe(II) sulphates with diphenyl-4-amine barium sulphonate (DAS) Synthesis,thermogravimetric and spectroscopic studies

Reactions in aqueous-alcoholic solution between diphenyl-4-amine barium sulphonate (Ba-DAS—anionic surfactant) and the hydrated sulphates of Fe(III) and Fe(II) ions and their use to ovtain iron oxides are described here. The formation of Fe(II) complexes was reached by using an excess of Ba-DAS, in absence of light under inert atmosphere. The complexes achieved Fe₂[(C₁₂H₁₀NO₃S)₄]·9H₂O and Fe₃[(C₁₂H₁₀NO₃S)₆]·12H₂O were characterized by TG/DTG and IR, UV-VIS and ⁵⁷Fe-Mössbauer analyses.     

Novel devices for solvent delivery and temperature programming designed for capillary liquid chromatography

Analyses in chromatographic systems able to save mobile and stationary phases without reducing efficiency and resolution are of current interest. These advantages regarding savings have challenged us to develop a system dedicated to miniaturized liquid chromatography. This paper reports on the development of a high‐pressure syringe‐type pump, an oven able to perform isothermal and temperature programming and a software program to control these chromatographic devices. The experimental results show that the miniaturized system can generate reproducible and accurate temperature and flow rate. The system was applied to the separation of statins and tetracylines and showed excellent performance.     

Influence of plasticizer type on the properties of polymer electrolytes based on chitosan

Polymer electrolytes were obtained by the casting technique from a solution containing chitosan, hydrochloric acid, and plasticizer such as glycerol, ethylene glycol, and sorbitol. The transparent membranes with good ionic conductivity properties were characterized by impedance and UV-vis spectroscopies, thermal analysis (DSC), and X-ray diffraction. The best ionic conductivity values of 9.5 x 10(-4) S cm(-1) at room temperature and 2.5 x 10(-3) S cm(-1) at 80 degrees C were obtained for the sample containing 59 wt% of glycerol and an equimolar amount of HCl with respect to NH2 groups in chitosan. The temperature dependence of the ionic conductivity exhibits an Arrhenius behavior with activation energy of 16.6 kJ mol(-1). The thermal analysis indicates that both glass transition temperature (-87 degrees C) and crystallinity are low for this electrolyte. The samples with 13 wt% of LiCF3SO3 showed that the ionic conductivity values of 2.2 x 10(-5) S cm(-1) at room temperature and 4 x 10(-4) S cm(-1) at 80 degrees C are predominantly amorphous and showed a low glass transition temperature of about -73 degrees C.