The Preparation Of Hybrid Molecular Imprinted Monolith And Their Application In Solid Phase Microextraction

The organic-inorganic hybrid molecular imprinted monolith (HMIM) has the advantages in high selectivity, high mass transfer rate, low backpressure, the ease of preparation, and so on. At the same time, it overcomes the drawbacks of organic and inorganic molecularly imprinted polymer, which has some characteristics such as a large specific surface area, high mechanical strength and non-swelling. As a result, it is able to highly selective enrichment of trace components in complex samples. In this paper, the good separation and durable hybrid molecularly imprinted monoliths have been prepared in a micro pipette tip, and they were used as solid phase microextraction materials in the pretreatment process of complex samples. Selective, sensitive and rapid analytical methods for the determination of some trace compounds in food, cosmetics. environmental samples were established. The main content of this paper is as follows:(1) After optimizing the polymerization conditions, the2,4-dichlorophenoxyacetic acid (2,4-D) hybrid molecular imprinted monolith was prepared in a micro pipette tip by in situ polymerization. The structure and selective performance of the HMIM were evaluated by infrared spectrum, scanning electron microscope and HPLC, compared with the HNIM. The HMIM showed highly specific recognition for the template2,4-D, the imprinted factor of the monolith for2,4-D reached3.29. Then, this material was applied to separation and concentration of2,4-D in rice samples. By optimizing the extraction conditions, high selectivity analytical method for separation of2,4-D in rice had been developed. The experimental results showed that the linear ranges were167-4167μg/kg for2,4-D in rice with the correlation coefficient of above0.9966. The detection limits (s/n=3) were50μg/kg.(2) A2,4-dihydroxydiphenylketone (2,4-DHBP) HMIM was prepared by sol-gel method while2,4-DHBP was used as the template, and the synthesis conditions such as the proportion of organic and inorganic components, the dosage of coupling agent were optimized. The structure and selective performance of HMIM were evaluated by infrared spectrum, scanning electron microscope and HPLC. The HMIM was used in solid phase microextraction. Several parameters were investigated, including the volume and flow rate of sample, the type and volume of extraction solvent, and so on. A rapid, efficient and high selectivity analytical method for the determination of2,4-DHBP in toner was established.(3) For avoiding the template-leakage, a HMIM was prepared in a micro pipette tip with the the analogues of4-HBP as the template by optimizing the synthesis conditions. The monolith displays good recognition properties for4-hydroxy diphenylketone (4-HBP). Then, the HMIM was applied for the selective extraction of4-HBP in water samples, As a consequence, a more sensitive and accurate analytical method for determination4-HBP was developed. The experimental results showed that the linear ranges were1-500ng/mL for4-HBP in water with the good linearity, intra-and inter-day precisions meet the request of quantitative analysis.