Preparation Of Monolithic Silica Column And Investigation Of Its Chromatographic Characteristics

Monolithic column is a new separation material which has attracted much attention of scientists since 1990s. Monolithic silica column is the new type column of chromatography which possessed high permeability, low column back pressure, high mechanical strength and column efficiency. It is well suited for high speed and high efficiency separations and it will play more and more important role in analysis and separation.This paper consists of the following parts: monolithic silica column's preparation, principle, characterization and application.First, a new approach of preparing monolithic silica column was developed by adopting an improved sol-gel technology with tetramethoxysiane and polyethylene glycol as the matrix materials in this paper. The effects of the misture pH value and temperature of water-bath in the process of gelation were investigated. The influences of different TMOS/PEG ratio and concentration of porogenic diluent on monolithic silica column, the change of Si-OH content of monolithic column with roasting temperature and the mesopore size on the skeleton with reaction conditions were also discussed. The problems of crack and deformation in preparing the column were solved by using N,N-dimethylformamide and a new heat treatment procedure.Second, column back-pressure as a function of the flow-rate on the monolithic silica column was investigated. The optimal of preparation monolithic column were determined. The monolithic silica column was then applied to the separation of benzene substituted compounds and they were baseline-separated in normal-phase chromatography. Nitropheol isomers were also successfully separated on a 3 -CD bonded monolithic silica column.