Molecularly Imprinted Sensor Based On Nano Materials For Quinolones

Quinolones(QNs)belong to the family of synthetic broad-spectrum antimicrobial agent which are derived from Nalidixic acid.QNs can prevent bacterial breeding by disrupting the replication,transcription and repair of bacterial gene.They show striking potency against Gram-negative bacilli,Gram-positive bacilli,and have been used in human and veterinary medicine to treat gastrointestinal,respiratory diseases,urinary tract infections,due to their broad-spectrum antibacterial activity,good bioavailability,few side effects and excellent tissue penetration.However,the antibacterials were widely used even misused,resulting in occurrence of residues drug in animal foodstuffs.So it is necessary to explore a rapid and accurate technique for detection of QNs.In this paper,we focus on the preparation of three sensors combining molecular imprinted polymers(MIPs)with nano materials for detecting ciprofloxacin,norfloxacin and enrofloxacin,after introducing the molecular imprinted electrochemical sensors and nano materials briefly.The the preparation conditions of sensors were studied,meanwhile the performance of the sensors in all aspects was evaluated.The main contents of the summary are as follows:(1)A novel electrochemical sensor based on ciprofloxacin molecularly imprinted polypyrrole film on an AuNPs modified glassy carbon electrode was fabricated.The preparation conditions were optimized and performance of the sensors was explored by square wave voltammetry(SWV)using K3[Fe(CN)6] as probe.Furthermore the performance was compared with the sensor that was not modified by AuNPs.The linear relationships between current difference and logarithmic concentration were obtained in the range from 1.0×10-9 to 5.0×10-3 mol/L with the detection limit of 7.78×10-12 mol/L.This ciprofloxacin sensor has higher sensitivity,better selectivity and reproducibility than the sensor without modified.The test in real samples also has good results.(2)A highly sensitive and selective MIPs sensor combined with graphene was developed for the determination of norfloxacin.The MIPs film was synthesized by electropolymerization selecting norfloxacin as template and pyrrole as functional monomer.Compared with the sensor without graphene modification,surface area,sensitivity and other properties of the sensor were improved.Under the optimized experimental conditions,the determination concentrations range of norfloxacin is 1×10-9-5×10-3 mol/L and the limit of detection is 4.16×10-11 mol/L.This sensor displayed a good reproducibility and stability,and was applied for detection of norfloxacin in real drug samples with satisfying results.(3)In this study,a excellent sensitive and selective electrochemical sensor for enrofloxacin was developed by electropolymerization of a MIPs film onto a glass carbon electrode modified by AgNPs.The MIPs film was synthesized using cyclic voltammetry in acetic acid buffer solution in the presence of enrofloxacin as template molecules and pyrrole as functional monomer.SWV was employed to evaluated the modified sensor and non-modified sensor.The results show that linear ranging from 1×10-9 mol/L to 5×10-3 mol/L for the detection of enrofloxacin was observed with the detection limit of 2.21×10-12 mol/L.Many properties of this sensor were promoted when AgNPs was introduced into this sensor,such as shorter time of elution and adsorption,more excellent sensitivity and wider detection range.