Synthesis and characterization of organic–inorganic mesoporous silica materials for use as stationary phases for solid phase extraction (SPE) and HPLC columns

M.Sc. (Chemistry)According to the International Union of Applied Chemistry (IUPAC) mesoporous silica materials are a class of materials which contain pore size with diameters ranging from 2 to 50 nm. Due to their attractive features such as large surface area along with tunable pore size, accessible silano groups and easy functionalization make them with special properties to be employed as stationary phases for different chromatographic applications such as clean up, preconcentration, purification and separation of analytical samples. Organic–inorganic mesoporous hybrid materials are a new class of materials obtained when an inorganic material, such as mesoporous silicas are surface modified using an organic material via silylation. The main advantage of these hybrid materials is that they are formed by combining dissimilar properties of inorganic and organic materials into one material. Whereas the inorganic materials provide rigidity and thermal stability, the organic components provide flexibility, dielectric, ductility, and processability. Therefore the advantages of these hybrid materials lead them to be used over a wide range of applications. The main objective of this study was to synthesize organic-inorganic hybrid mesoporous silica materials for use as stationary phases for solid phase extraction and high performance liquid chromatography columns. The materials were prepared under basic conditions using silica gel and tetraethyl orthosilicate used as a source of silica and modified by either surface polymerization or grafting methods using octadecyltrimethoxysilane followed endcapping with hexamethyldisilazane. The materials were characterized before and after surface modification using different analytical methods. Scanning electron microscopy (SEM) pictures showed that the morphology of the materials remained unchanged after surface modification