Study On The Electrochemical Detection Of Several Banned And Restricted Fishery Drugs In Marine Fishery Environment

Nitrofurazone (NF), semicarbazide (SEM) and crystal violet (CV) is the banned or restricted drugs in aquaculture and fishery production. Their illegal or excessive use is not only threatening food security, but also causes environmental pollution. Based on the electrochemical sensors prepared with conductive carbon paste electrode (CCBPE) or carbon ionic liquids paste electrode (CILE), quickly electrochemical methods were developed for the determination of NF, SEM and CV. The presented methods have important significance for the evaluation of food safety and environmental pollution.The main works of this paper include the following content:1. Based on CV was controlled by adsorption, and irreversible oxidation reaction occurred at CCBPE in transferring two electrons, an electrochemical sensor was prepared to detect CV as fisheries drug. After the experimental parameters, including accumulation time, accumulation potential, pH of supporting electrolyte etc. were optimized, it was found that the semi-differential pulse voltammetric anodic peak value (/pa1) of CV is proportional to its concentration in the range of0.03～1.30μmol/L with a detection limit of10.0nmol/L (S/N=3). Thereby, an electrochemical method was developed for rapid detection of CV. The presented method has been successfully applied to monitor trace CV in six kinds of freshwater fishing waters, displaying the relative standard deviation (RSD) is less than10.7%(n=5) and the average recovery of97.1%.2. CILE was prepared by using n-octylpyridinium hexafluorophosphate instead of liquid paraffin oil as the binder. In acetate buffer solution of pH6.0, the irreversible electrode reaction for NF controlled by adsorption was found on CILE. Under the conditions of optimized parameters, including buffer solution, pH, accumulation time, the reduced peak current ipc (μA) of NF with its concentration C (μmol/L) in0.02-0.80μmol/L ranged linear relationship (ipc=33.99C+1.778, R=0.9937) with detection limit of0.012μmol/L (S/N=3).3. Voltammetric behaviors SEM were investigated by employing CILE. In acetate buffer solution of pH4.0, a well-defined oxidative peak of SEM was obtained, attributing to the irreversible and adsorption-controlled electrode reaction with2electrons participation. The values of apparent heterogeneous electron transfer rate constant k’s with the redox are0.0061s-1. After the experimental parameters for influencing the voltammetric responses was optimized, such as supporting electrolyte, pH, accumulation time and accumulation potential, etc. It is found that the anodic peak current of SEM is proportional to its concentration in the range of4.00～40.0μmol/L with detection limit of0.17μmol/L (S/N=3).4. Based on electrochemical behavior of NF and SEM at CILE, the sequenced measurement method for NF and SEM was studied with CILE as electrochemical sensor. Selecting5.0as the optimized pH of buffer solution for the sequential determination of NF and SEM, when NF and SEM coexistence, the linear range of both were0.10～2.10and13.3～66.6μmol/L, the detection limit was71.0nmol/L and0.30μmol/L, respectively. Determination for residues of both in water fisheries showed that the average recoveries was87%and90%, respectively.