title: Modelling of the impedimetric responses of an aflatoxin B(1) immunosensor prepared on an electrosynthetic polyaniline platform.
abstract: Aflatoxins are a group of mycotoxins that have deleterious effects on humans and are produced during fungal infection of plants or plant products. An electrochemical immunosensor for the determination of aflatoxin B(1) (AFB(1)) was developed with AFB(1)antibody (AFB(1)-Ab) immobilized on Pt electrodes modified with polyaniline (PANi) and polystyrene sulphonic acid (PSSA). Impedimetric analysis shows that the electron transfer resistances of the Pt/PANi-PSSA electrode, the Pt/PANi-PSSA/AFB(1)-Ab immunosensor and Pt/PANi-PSSA/AFB(1)-Ab incubated in bovine serum albumin (BSA) were 0.458, 720 and 1,066 kOmega, respectively. These results indicate that electrochemical impedance spectroscopy (EIS) is a suitable method for monitoring the change in electron transfer resistance associated with the immobilization of the antibody. Modelling of EIS data gave equivalent circuits which showed that the electron transfer resistance increased from 0.458 kOmega for the Pt/PANi-PSSA electrode to 1,066 kOmega for the Pt/PANi-PSSA/AFB(1)-Ab immunosensor, indicating that immobilization of the antibody and incubation in BSA introduced an electron transfer barrier. The AFB(1) immunosensor had a detection limit of 0.1 mg/L and a sensitivity of 869.6 kOmega L/mg.
authors.affiliation: Sensor Research Laboratory, Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville, Cape Town, South Africa.
authors.forename: Joseph H O
authors.initials: JH
authors.lastname: Owino
authors.forename: Anna
authors.initials: A
authors.lastname: Ignaszak
authors.forename: Amir
authors.initials: A
authors.lastname: Al-Ahmed
authors.forename: Priscilla G L
authors.initials: PG
authors.lastname: Baker
authors.forename: Hailemichael
authors.initials: H
authors.lastname: Alemu
authors.forename: Jane Catherine
authors.initials: JC
authors.lastname: Ngila
authors.forename: Emmanuel I
authors.initials: EI
authors.lastname: Iwuoha
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis*; D000814:Aniline Compounds / Q000032:analysis* / Q000737:chemistry; D015374:Biosensing Techniques; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D017097:Electric Impedance; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004583:Electrons; D006801:Humans; D008962:Models, Theoretical; D009183:Mycotoxins / Q000032:analysis*; D011108:Polymers / Q000737:chemistry; D011137:Polystyrenes / Q000032:analysis; D012710:Serum Albumin, Bovine / Q000032:analysis
chemical_list: D000814:Aniline Compounds; D009183:Mycotoxins; D011108:Polymers; D011137:Polystyrenes; C416807:polyaniline; D012710:Serum Albumin, Bovine; C003321:polystyrene sulfonic acid; D016604:Aflatoxin B1; C023650:aniline