Modelling of the impedimetric responses of an aflatoxin B1 immunosensor prepared on an electrosynthetic polyaniline platform

Joseph H.O. Owino, Anna Ignaszak, Amir Al-Ahmed, Priscilla G.L. Baker, Hailemichael Alemu, Jane Catherine Ngila, Emmanuel I. Iwuoha

Research output: Contribution to journalArticlepeer-review

58 Citations (Scopus)

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 B1 (AFB1) was developed with AFB1antibody (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/AFB1-Ab immunosensor and Pt/PANi-PSSA/AFB1-Ab incubated in bovine serum albumin (BSA) were 0.458, 720 and 1,066kΩ, 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 kΩ for the Pt/PANi-PSSA electrode to 1,066kΩ for the Pt/PANi-PSSA/AFB1-Ab immunosensor, indicating that immobilization of the antibody and incubation in BSA introduced an electron transfer barrier. The AFB1 immunosensor had a detection limit of 0.1 mg/L and a sensitivity of 869.6 kΩ L/mg.

Original languageEnglish
Pages (from-to)1069-1074
Number of pages6
JournalAnalytical and Bioanalytical Chemistry
Volume388
Issue number5-6
DOIs
Publication statusPublished - Jul 2007
Externally publishedYes

Keywords

  • Aflatoxin B
  • Aflatoxin B antibody
  • Differential pulse voltammetry
  • Electrochemical impedance spectroscopy
  • Immunosensor

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry

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