Synthesis And Usage Of Tebuconazole Based Molecularly Imprinted Polymers In Analysis Of Biological And Environmental Samples

Molecular imprinting is a technology to make receptor-like polymers based on the molecular recognition theory. Molecularly imprinted polymers (MIPs) have shown advantages such as pre-determined selectivity and chemical stability in many analytical areas and have become a potential stationary phase in the solid-phase extraction. The combination of MIPs and solid-phase extraction (namely molecularly imprinted solid-phase extraction, MISPE) has been used in determining trace analytes in drug, biological and environmental samples. The application of MIPs in SPE has become the most promising development of selective SPE method for trace analysis.Triazole fungicides comprise about 25 commercial agrochemicals such as tebuconazole(TBZ), hexaconazole(HXZ), flutiafol (FTF), and penconazole (PNZ). And they are well known as curative fungicides, usually applied to the plant after initial infection before it produces visible symptoms. Most of the triazole fungicides are widely used against rusts, powdery mildews and scabs. But triazole fungicides were harmful to fish and other aquatic organisms. And the Environmental Protection Agency (EPA) has classified TBZ as a "possible human carcinogen" because it caused significant toxicity and reproductive effects on laboratory mice.In this research, tebuconazole was chosen as the template. By optimizing the preparing conditions, TBZ imprinted polymers were used to determine the trace amount of TBZ in biological and environemtal samples (cabbage, pannage, shrimp, orange juice and tap water) in an off-line mode for the first time. The major topics in the thesis include:1. The progress of basic theory, synthesis and application of molecular imprinting polymers were reviewed.The development and application of MIPs in MIP-SPE (MISPE) were emphasized.2. Molecularly imprinted polymers (MIPs) were prepared with tebuconazole as the template molecule and MAA, 4-VP or MAA&4-VP as monomer. Frontal chromatography, selectivity experiment and the on-line separation experiment were used to determine the binding capabilitys, binding specificity and separation efficiency of different MIPs. It was showed that the binding selectivity and capability and separation efficiency were the highest when the ratio of template molecule and monomer was 1:3 and 4-VP: MAA =1:1.3. A polymer that had the highest binding selectivity and capability was used as solid-phase extraction (SPE) sorbents for direct extraction of TBZ from different biological and environmental samples (cabbage, pannage, shrimp, orange juice and tap water). The extraction protocol was optimized. The optimized MISPE protocol was:conditioning with 5mL methanol: acetic acid=9:1, 5mL methanol and 5mL water respectively, loading with 5mL aqueous samples, washing with 1.2mL acetonitrile: phosphate buffer =5:5 (pH=3), and eluting with 3mL methanol. And under the optimum conditions MIPs can selectively recognize, effectively trap and pre-concentrate of TBZ over a concentration range of 0.5-15μmol/L. The intra-day and inter-day RSD are less than 9.7% and 8.6% respectively. Under the optimal condition, MISPE recoveries of spiked cabbage, pannage, shrimp, orange juice and tap water were 62.32%, 75.80%, 71.67%, 89.07% and 93.94% respectively. Compared with C18 SPE(the recoveries were47.31%, 59.83%, 46.76%,77.35%, 86.48%respectively) and strong cation exchange(SCX)SPE ( the recoveries were 30.84%, 36.32%, 40.28%, 67.46%, 75.27%respectively), better HPLC separation efficiency and higher recoveries were achieved after MISPE.It was showed that the imprinted polymer has good affinity and marked selectivity for the template molecule, and can be used to determine the trace amount of TBZ in biological and environemtal samples in an off-line mode. This methodology may be important for accurate investigation and determination of TBZ levels in the environmental and biological matrices.