Study On Molecularly Imprinted Sensing Analysis For The Detection Of Olaquindox

Olaquindox as a quinoxaline drug is widely used to improve feed conversion efficiency and promote animal growth.However,studies have shown that excessive use of olaquindox potentially harms animals,humans and the environment.So far,classical analytical methods have been developed for detecting olaquindox,such as high-performance liquid chromatography(HPLC),liquid chromatography tandem mass spectrometry(LC-MS/MS)and enzyme-linked immunosorbent assay(ELISA).However,chromatography methods are complicated in procedure,time-consuming and expensive.Therefore,it is of great urgency for food safety to develop a fast and simple method for estimation of olaquindox(OLA).In this paper,an advanced molecularly imprinted electrochemical sensor(MIECS)based on electropolymerizing surface molecularly imprinted polymer thin film on a modified glassy carbon electrode(GCE)was developed for the detection of OLA.It was fabricated by coating dopamine@graphene(DGr)on GCE,then electropolymerizing pyrrole(Py)and molecularly imprinted polymers(MIPs).Graphene(Gr)was introduced for improving conductivity and sensitivity.Dopamine(DA)was used for dispersion and adhesion of Gr.Polypyrrole(PPy)could fix DGr and enhance the current response evidently.The established sensor could selectively recognize OLA but not the analogs of OLA.Some essential parameters controlling the performance of the developed sensor were investigated and optimized.Under optimal conditions,the linear relationship between the current intensity and OLA concentration was obtained from 13?g L-1 to 131.6 ?g L-1 with a limit of detection(LOD)of 1.97 ?g L-1.Analytical results of OLA for fish and feedstuffs showed a good agreement with the results based on HPLC.A novel quartz crystal microbalance sensor(QCM)was prepared for rapid determination of OLA based on electropolymerizing MIPs thin film on the quartz crystal gold electrode(AuE),which was utilized as the recognition element.The sensor was only constructed by one-step electropolymerization process.The functional monomer and target were o-phenylenediamine(oPD)and OLA,respectively.Through the evaluation,the constructed sensor had a linear relationship between the frequency shifts and OLA concentration ranging from 157.95 ?g L-1 to 421.2 ?g L-1 with a limit of detection of 110 ?g L-1.Analytical results of OLA for fish and chicken were in according with the results based on HPLC.