Determination Of Fishery Drugs Residues In Aquatic Products By Modified Electrode Electrochemical Method

Drug residue is one of the main problems related to the quality and safety of aquatic products in china.Drug residue is becoming more and more serious due to the high diseases incidence of aquatic animals caused by environmental contamination and planting resources degradation and abuse of drugs by aquaculturists.Long term intake of food containing excessive amounts of drug residues will make antibiotics accumulated in the body and endanger human health.The problem of antibiotic residues in food has been paid more and more attention by many countries in the world,and many countries have established the maximum residue limits.However,there are some limitations in the traditional methods for the detection of antibiotics.Therefore,it is necessary to explore a sensitive and effective method for the detection of antibiotics.In this study,malachite green（MG）molecular imprinted electrochemical sensor,ciprofloxacin（CIP）molecularly imprinted electrochemical sensor and nickel-trimesic acid metal organic framework material electrochemical sensor were established and used for the determination of MG,CIP and chloramphenicol（CAP）,respectively.These sensors have low detection limit,wide linear range,good reproducibility and stability.The results are as follows:1.Establishment of MG molecular imprinted electrochemical sensor:A molecular imprinted polymer（MIP）on the surface of a glassy carbon electrode（GCE）was prepared by electropolymerization of o-aminophenol（OAP）in the presence of MG in the sodium perchlorate（NaCIO4）solution using cyclic voltammetry（CV）.The electrochemical performance of the sensor was studied using differential pulse voltammetry（DPV）.The results showed that the peak current difference increased with the MG concentration in the range 0.02～0.5 μg/mL with a calibration equation of I（μA）=26.7733CMG+2.6625（μg/ml）and in the range 0.5～2.5μg/mL with a calibration equation of I（μA）=2.662CMG+14.253(（μg/ml）.The detection limit is 1.2×10-2μg/mL.The MIP electrode exhibited good selectivity and reproducibility,and the MIP electrode could be applied to the determination of MG in samples.2.Establishment of CIP molecular imprinted electrochemical sensors:A MIP on the surface of a GCE was prepared by electropolymerization of o-phenylenediamine and resorcinol in the presence of CIP in the sodium perchlorate（NaCIO4）solution using CV.The electrochemical performance of the sensor was studied using DPV.The results showed that the peak current difference increased with the CIP concentration in the range 0.13～1.3μmol/L with a calibration equation of I（μA）=7.2402 CCIP+1.0896（μmol/L）and in the range1.3-6.5μmol/L with a calibration equation of I（μA）=2.8877 CCIp+6.804（μmol/L）.The detection limit is3.7×10-8 mol/L.The MIP electrode exhibited good selectivity and reproducibility,and the MIP electrode could be applied to the determination of CIP in samples.3.Establishment of metal-organic frameworks-based electrochemical sensors:nickel（Ⅱ）trimesic acid Ni3（BTC）2 metal organic-frameworks（MOFs）was synthesized through a facile template-free hydrothermal method.Then the hybrid material of Ni3（BTC）2 and sodium polyacrylate PAAS was cast on the GCE electrode to get a modified electrode Ni3（BTC）2-PAAS for the electrochemical detection of CAP.The electrochemical study showed that the Ni3（BTC）2 metal organic-frameworks exhibited the high catalytic effect on the reduction of CAP.The results showed that the peak current difference increased with the CAP concentration in the range of 3.1×10^-9mol L～1.55×10^-7mol L with a calibration equation of I（μA）= 139.72 C_CAP+9.9616（mol L,R²=0.9988）and in the range of 1.55×10^-7mol L～9.3×10^-7mol L with a calibration equation of I（μA）= 33.109 C_CAP+ 26.596（mol L,R² = 0.9993）.The detection limit is 2.0 × 10^-9mol L.