An Electrochemical Biosensor Based On Electrochemical Conversion Of Magnetic Nanoparticles For Chloramphenicol Detection

Antibiotics residue has been one of the most serious threatens for food safety,and the rapid detection of antibiotics is needed.Electrochemical biosensor is a type of sensors characterized by the specific capture of target analyte with bio-receptors and the detection through electrochemical reaction,which has the features of high specificity,high sensitivity and less detection time.Electrochemical biosensors using magnetic nanoparticles(MNPs)for separation and enrichment significantly improve detection performance and simplify the operation.However,these studies mainly focused on the magnetic properties of MNPs,leaving their roles as signal labels rarely exploited.First,in this thesis,the literature on antibiotics detection for food safety is reviewed,and then two electrochemical biosensors are proposed by integrating the magnetic separation/concentration with signal generation for the detection of chloramphenicol()in food.In the design and fabrication of these two biosensors,not only the magnetic properties of MNPs were fully explored,but also a new way to generate a signal through the electrochemical conversion of MNPs to electrochemically active Prussian blue(PB)was developed,thus the generation and amplification of signals without any additional labels were realized.The biosensors exhibited satisfactory performance for the detection of CAP with a detection limit down to 1 ng mL-1,the detection range is from 1 ng mL-1 to 10000 ng mL-1 as well as good specificity and stability.Moreover,the biosensors worked well for the detection of CAP in milk and river-water samples.The recovery rates of "Signal-off" biosensor for CAP in milk and river-water are 82%～113%and 89%～94%,respectively,and the recovery rates of "Signal-on" biosensor for CAP in milk and river-water are 87.2%～113.6%and 88.2%～109.6%,respectively.The two developed methods may lead to a new concept for rapid and facile biosensing technique with applications in the fields of food safety,clinic diagnosis/therapy and environmental monitoring.