Electrochemical sensors for detection of tetracycline antibiotics
2012
Gayah, A. R. | Hazana, R. | Azima, A. | Nur Azura, M. S. | Faridah, S. | Zamri, I. | Norzaili, Z.
An electrochemical immunosensor based on screen-printed carbon working electrode with onboard carbon counter and silver–silver chloride pseudo-reference electrode for tetracycline antibiotic detection is described in this paper. A direct competitive enzyme-linked immunosorbent assay (ELISA) format was first developed and optimized on the surface of a carbon screen-printed working electrode by immobilizing the capture antibody (polyclonal) using electro-deposition of gold nanoparticles conjugated with polyclonal anti- tetracycline antibodies. The detection reagent, tetracycline-Horseradish Peroxidase (HRP) conjugate was used as an enzyme label. Electrochemical detection was then carried out using 3,3’,5,5’-tetramethylbenzidine dihydrochloride (TMB) /H2O2 as the enzyme mediator /substrate system and conducted using chronoamperometry at 300mV vs. onboard screen-printed Ag-AgCl pseudo- reference electrode. Tetracycline detection of 10 ppb was achieved. The optimal sensor configuration was then compared to a commercial ELISA kit method for analyzing meat samples. The sensor was also capable to detect four derivatives of tetracycline tested such as Oxytetracycline, Doxycline, Chlortetracycline and Demeclocycline. The sensor showed good selectivity for tetracycline with higher recovery percentage (70 - 95%) in the presence of other antibiotics in the sample. It also showed very high sensitivity using the amplification strategy applied with the use of gold nano-particles. This makes the developed sensor a potential tool for a rapid, simple and sensitive detection of tetracycline residues in poultry products.
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