Detecting penicillin G in milk with impedimetric label-free immunosensor.
A label-free impedimetric flow injection immunosensor for the direct detection of penicillin G has been developed. Anti-penicillin G was immobilized on a gold working electrode modified with a self-assembled monolayer of thioctic acid. Real time monitoring of impedance was carried out at the optimum frequency of 160 Hz. Under optimum operating conditions the system provided a wide linear range between 1.0 x 10(-13) and 1.0 x 10(-8) M with a very low detection limit of 3.0 x 10(-15) M, much lower than the MRL of penicillin G in milk (1.2 x 10(-8) M). The immobilized anti-penicillin G on self-assembled thioctic acid monolayer gold electrode was very stable and provided good reproducible signal after regeneration up to 45 times with a relative standard deviation (R.S.D.) lower than 4%. Good recoveries and precisions were obtained when spiked raw milk samples were analyzed.
Thavarungkul
Panote
P
Biophysics Research Unit: Biosensors and Biocurrents, Prince of Songkla University, Hat Yai, Songkhla, Thailand. panote.t@psu.ac.th
Dawan
Supaporn
S
Kanatharana
Proespichaya
P
Asawatreratanakul
Punnee
P
D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation; D004563:Electrochemistry; D007118:Immunoassay; D008892:Milk / Q000737:chemistry*; D010400:Penicillin G / Q000032:analysis*; D015203:Reproducibility of Results
D010400:Penicillin G