title: Amperometric immunosensor based on polypyrrole/poly(m-pheylenediamine) multilayer on glassy carbon electrode for cytokinin N6-(Delta2-isopentenyl) adenosine assay.
abstract: A novel immunosensor based on a multilayer-coated glassy carbon electrode was designed to determine isopentenyl adenosine (iPA) in plants. The multilayer consists of polypyrrole and poly(m-phenylenediamine) with K4Fe(CN)6 and horseradish peroxidase (HRP) entrapped during electropolymerization. The ferrocyanide doped in polypyrrole functions as the mediator. The glucose oxidase bound on the immunosensor by the competitive immunoreaction involving iPA catalyzed the oxidation of the added glucose with the formation of H2O2, which is in turn reduced in the presence of HRP entrapped in poly(m-phenylenediamine). The current of the oxidized production of ferrocyanide reduced at -50 mV is inversely proportional to the concentration of iPA in the competitive immunoreaction. This immunosensor is able to be used about 40 times; after that its surface can be regenerated for a new immunosensor assembly by washing with 0.1M citrate-phosphate buffer (pH 4.6). The percentage of current response reduction (CR%) (y) is linearly related to the logarithm of the concentration of iPA (x) in the 5-300 microg/ml range, with a regression equation of the form y = 42.13x - 27.79 and a correlation coefficient of 0.9861. Five hybrid rice grain samples were analyzed with results in satisfactory agreement to those obtained by high-performance liquid chromatography.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, Chemistry and Chemical Engineering College, Department of Environmental Science and Engineering, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.forename: Lang-Tao
authors.initials: LT
authors.lastname: Xiao
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Zeng
authors.forename: Guo-He
authors.initials: GH
authors.lastname: Huang
authors.forename: Guo-Li
authors.initials: GL
authors.lastname: Shen
authors.forename: Ru-Qin
authors.initials: RQ
authors.lastname: Yu
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D002021:Buffers; D002138:Calibration; D002244:Carbon / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003583:Cytokinins / Q000032:analysis*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D005292:Ferricyanides / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D005947:Glucose / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007124:Immunoenzyme Techniques / Q000295:instrumentation* / Q000379:methods*; D007541:Isopentenyladenosine / Q000032:analysis* / Q000276:immunology; D012275:Oryza / Q000737:chemistry; D010655:Phenylenediamines / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D011817:Rabbits
chemical_list: D002021:Buffers; D003583:Cytokinins; D005292:Ferricyanides; D010655:Phenylenediamines; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D002244:Carbon; D007541:Isopentenyladenosine; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D005947:Glucose; C008381:3-phenylenediamine