Study On The Molecularly Imprinted Memberan-based Sensor For The Detection Of Chloramphenicol Succinate Residue

Chloramphenicol (CAP), one of the broad-spectrum antibiotics, was once widely used in husbandry. However, residue of CAP in animal food has strong toxicity and side-effects, which was serious threat to human health. Hence, CAP was restricted or even banned in use for edible animal and its maximal residual was strictly regulated in animal foodstuff in most of the developed western countries. The Ministry of Agriculture of the People's Republic of China declared formally that CAP and other kinds of CAP derivates should not be detected out in the edible tissues of animal food. Nevertheless, because of its low price and steady effectiveness against bacteria, CAP is still illegally used in livestock and aquaculture. Up to now, the main approaches for the detection of CAP residue include immunoassay, chromatography, multiple techniques of chromatography linked with mass spectrum. However, these methods have their own disadvantages, such as complex analyzing processes, long time preparation of samples and expensive equipments.To develop a sensor based on molecularly imprinted films (MIF) and establish a new-method for the detection of chloramphenicol succinate (CAPS) through this sensor. Photopolymerization method was applied for the synthesis of the molecularly imprinted micro-particles of HS-CAP using methylacrylic acid as functional monomer, ethylene glycol dimethacrylate as the cross-linking agent and HS-CAP as the template. Superficial characteristic of the imprinted micro-particles was analyzed by electron microscope scanning. Ultraviolet spectrophotometry and scatchard equations were used for the investigation of the adsorption ability and its kinetics; Photo-polymerization method was applied to prepare MIF, superficial characteristic of the MIF was analyzed by electron microscope scanning. The absorptive characteristics of this MIF was identified by absorbing experiment; Screen printed electrode (SPE) was designed and prepared by cooperation with other unity, the conductibility, reproducibility and stability of this SPE was measured throug a series of tests; A sensor based on SPE for the detection of CAPS was assembled after the SPE was connected with an electrochemical analyzer through an electrode slot, standard curve for CAPS detection was established and analysis of CAPS in milk samples was carried out. The performance of this sensor was tested by Interference experiment, recovery analysis and other testing. A great number of imprinted micro-pores with specific recognizing sites was formed in the surface of the imprinted micro-particles with a diameter ranging over 0.2-0.5μm. Maximum adsorption quantity of the imprinted micro-particles reaches as high as 13.66μmoL/g and equilibrium dissociation constant is 3.75 mmol/L. The preparation of moleculaly imprinted micro-particles for HS-CAP in this study is simple and the resultant imprinted micro-particles have strong recognizing capability towards template molecules; Scanning election microscopic images of the MIF showed that there were numerous imprinted micropores with a diameter about 100 nm on the surface of MIF. Compared with non-imprinted membrane(N-MIF), MIF has a good capacity of specifically absorbing the template molecules. The concentration of chloramphenicol succinate solvent changed significantly after being interacted with MIF. Most of this recognizing reactions were completed in the first 2 h and declined as the reaction time prolonged; The SPE with high conductibility, reproducibility and stability was prepraed finally; A sensor based on MIF was assembled and CAPS testing method was Established, The MIF-based sensor showed high sensitivity and specificity toward the target CAPS and the response of MIF-sensor to concentration of CAPS displayed a linear correlation over a range from 1×10^-8 mol/L to 1.2×10^-5 mol/L with a detection limit of 2×10^-9 mol/L. The recoveries reach 93.5%-95.5% based on milk samples. Through this reserch, a sensor based on MIF was developed, this sensor shows the advantage of high stability, low cost, short detecting time and low detection limit (2×10^-9 mol/L). We predicted that this type of sensor would have great prospect in practical use.