Desenvolvimento de novas fases estacionárias para cromatografia líquida

Abstract

The present work aims to develop a polar SP composed of a mixed oxide Li2O-ZrO2- BaO-SiO2, which was synthesized by the metal-chitosan complexation method. Initially an experimental design was made to evaluate the influence of the calcination parameters on the material properties, with the results was chosen a SP calcined at 350 ° C, because it has a larger surface area (280 m2 g-1). With this SP, chromatographic tests (HPLC) were performed to separate compounds from oxidation of benzyl alcohol (benzyl alcohol, benzoic acid, benzaldehyde and benzophenone). This same SP was also used in classical liquid chromatography (CLC) to separate mono (MAG), di (DAG) and triacylglycerides (TAG), where the separation of these compounds was not achieved. This SP tested presented a certain amount of organic matter (10.5%) when analyzed by TGA, so it was chosen another material, calcined at 700 ° C, which presented a smaller surface area (130 m2 g-1), but not It has organic matter in its composition. With this SP, the same HPLC chromatographic tests were performed, showing greater selectivity to benzoic acid. Testing was continued with compounds derived from benzoic acid (3- mercaptobenzoic acid, 3-cyanobenzoic acid and 3-dimethylamino benzoic acid). A univariate optimization of the chromatographic method was made, where it was possible to separate the 3 compounds, but with some coelution between two of them (ACNB and ADAB). The addition of TFA to MP was also tested, achieving a reduction in peak width but increasing coelution due to reduced retention time of He compounds. After the tests and evaluation of the column chromatographic efficiency, it is noted that there is a low number of theoretical plates, mainly due to the peak width, which can be caused by the SP particle size, particle diameter reduction is required.