Manufacture Of ADTZ Nano-modified Electrode And The Detection Of Matocystin ST

Objective:Sterigmatocystin is one kind of matocystin that can induce cancer and monstrosity. The decetion means of ST have been reported including TLC,HPLC,ELISA and PCR which examine genes related with ST biosynthesis. Most of these measures are complicated and time-consumed. Under this situation,this paper used activated multiwall carbon nanotubes as immobilized enzyme carrier and constructed Aflatoxin-detoxinfizyme biosensor in order to study the electrochemical information of ST . By the means ,ST is analyzed qualitatively and quantitatively and it can offer a new measure to detect ST quickly and easily.Methods:After fungi E-20 is cultured and fermented in 5 litre bottle, ion exchange chromatography and hydrophobic interaction chromatography were used to purify and prepare ADTZ respectively in association with native-PAGE to identify enzyme purification. Nanomaterial MWNT is refluxed with nitric acid in 100 boiling water.Then ADTZ is immobilized on the carrier of MWNT-COOH by means of adsorption or cross-linking.The voltammertric behavior of ST was studied by means of cyclic voltammogram analysis and different pulse analysis to get the peak potential ,peak current and the liner rang between ST concentration and peak current.Results:The purification rate and the specific activity of ADTZ by hydrophobic interaction chromatography is 10.92, 120.0U/mg,and is 4.46,68.08U/mg by ion exchange chromatography. Accordly the results of native-PAGE show that protein bands by hydrophobic interaction chromatography is less than ion exchange chromatography .TEM and IR spectra show that -COOH is introduced into the surface of MWNT after treatment with nitric acid refluxing beause there is a strong absorb at 1720nm wave length .At the same time ,the peak current is improved greatly with actived MWNT modifying Au electrode . Immobilized ADTZ electrode is used as work electrode to detect the peak potential of ST at scan rate 100mv/s in -lOOOmv 12000mv,and the CV graphy show the redox potential around -600mv,the oxide potential is about +400mv.the liner range is 4.16 10-5 1.33 10-3g/l,and the detection limit is 4.16 10-5 g/lConclusion:The specific activity of aim peak separated by hydrophobic interaction chromatography is obviously higher than that of ion exchange chromatography,and the number of electrophoresis bands are also less .All the results show that hydrophobic interaction chromatography is a better measure to purify and supply high quality ADTZ for manufacturing enzyme biosensor. MWNT is oxidated after refluxing with nitrate acid and -COOH is induced on the face which can supply the combination spot to enzyme. At the same time MWNT can improve the rate of transferring electron profoundly . Due to two roles of MWNT as good electron mediator and enzyme carrier combined with ADTZ catalysis , MWNT is a potential application nanomaterial on biosensor. With the ADTZ immoblized on the MWNT nanomaterial , we can detect the oxide-redox potential is +400mv and -600mv separately,and the liner detect range is 4.16 10-5 1.33 10-3g/l,the limit is 4.16 10-5 g/l.These results show that the enzyme biosensor with immobilized ADTZ on MWNT is a potential new means to determine low concentration ST in food and environment .