The Research Of Purification And Determination Methods For Microcystins Based On Host-guest Interaction

Microcystins draw more attention due to its carcinogenicity to liver and colon and its exits in food, such as drinking water, vegetables, fishes and shell. At present, it is necessary to build some fast, effective, simple, accurate and economic determination methods. Due to the low concentration of microcystins and coexistence of many other substrates in sample, it needs pre-treatment to reach higher concentration before measurement.In this study the gold nanoparticles were bimodified by both mono-6-thio-?-cyclodextrin and thiol phosphate, and then characterized by Infrared Spectrum, Wavelength Scanning and Agarose Gel Electrophoresis. The results demonstrated that the modification of gold nanoparticles was successful with a good absorption ability for microcystins and an excellent stability in solvent. The absorbance capability and static allocation coefficient were 2.125 ?g/mL and 5.666 respectively, which indicated that the specific recognition to microcystin can be achieved by the hose-guest interaction between tyrosine residue of microcystin and ?-cyclodextrin, and between arginine residue of microcystin and phosphate group.Based on excellent adsorption properties of bimodified gold nanoparticles to microcystin, an efficient solid phase extraction material(CTS-CD-P) was synthesized by modifying the chitosan with ?-cyclodextrin and phosphoric. The synthesized materials was proved to be modified successfully with Infrared Spectrum analysis. The adsorption capacity of CTS-CD-P was determinated by HPLC. The results illustrated the CTS-CD-P featured with a good absorbance property for microcystins. The highest adsorption capacity of CST-CD-P in solid and dissolved state reached 9.04 and 3.40 ?mol/g, respectively.This study established an electrochemistry determination method for microcystin based on differential pulse voltammetric analysis with bimodified gold nanoparticles which had a high adsorption capability of microcystin. Firstly the toluylene red was polymerized on glassy carbon electrode, then the positive charge of toluylene red polymer on the surface of electrode absorbed the gold nanoparticles which were bimodified by mono-6-thio-?-cyclodextrin and thiol phosphate. The microcystin was then determined by the modified glassy carbon electrode in phosphate buffer. The result showed that this method had a linear range of determination from 26 nM to 213 ?M and a detection limit of 19 nM, which was close to HPLC.