Research On Electrochemical Detection Methods For Three Common Harmful Substances In Food

The requirement for food is more and more, with the development of society, and the improvement of people's standard of living. However, series of serious food safety related accidents occurred recently have been endanger people's health and life quality seriously which have been concerned by different social fields. To this end, with the research and development of the researchers, the development of analytical techniques for toxic substances in the related food products gained rapid. But many traditional detecting is based on those instrumental analysis methods, and the operation is complicated and time consuming, so low cost, rapid analysis, high sensitivity, high selectivity of detection methods become the research hotspot. And electrochemical detection method can be well achieved those requests. In this paper, we continued to study the application of electrochemical detection method for third common ingredient in food dangerous analysis. Main research contents are as follows:A molecularly imprinted polymers sensor based a poly(p-aminobenzene salfonie acid) modified glassy carbon electrode by electrochemical polymerization, that is MIP/GCE was developed by means of electro-polymerization poly(p-aminobenzene salfonie acid) and melamine, then the melamine molecule on MIP/GCE was eluted with acetonitrile/water extraction solvent(1:1), at last developed a molecularly imprinted polymers sensor with special recognition function to melamine. The modified electrode was characterized by cyclic voltammetry. In conclusion, we can determine the optimum experimental conditions: the electrochemical polymerization with eighteen cycles of potential scans, the pH value of electrical aggregation buffer is 2.0, the optimal elution time is 2min and the pH value of detection buffer is 7.0. The modified electrode showed good response to melamine with a linear range from 8.0 nmol/L to 800 nmol/L and a detection limit of 2.7 nmol/L. Finally, The modified electrode was successfully used to detect the content of melamine in liquid milk, and the recovery was in the range from 98.5% to 112.2%. This modified electrode showed high sensitivity, selectivity and has broad prospects in application.Graphene Oxide/muti-walled carbon nanotubes complex loaded nano-sized gold rods were modified glassy carbon electrode by drop-coating to synthesis GO/MWCNTs/GNRs /GCE electrochemical sensing electrode. Under the optimum conditions, the electrochemical behavior of ractopamine on the GO/MWCNTs/GNRs /GCE was investigated by differential pulse voltammetry. GO/MWCNTs/GNRs /GCE showed good response to ractopamine with a linear range from 3.9×10-8 mol/L to 9.3×10-7 mol/L and a detection limit of 8.00×10-9 mol/L. The modified electrode showed high stability, selectivity and reproducibility. Finally, GO/MWCNTs/GNRs /GCE was successfully used to detect the content of ractopamine in pork serum samples with satisfying recoveries in the range of 94.5%-106.3%.Graphene is widely used for the preparation of sensors and the electric catalytic performance of Poly-amino acid in the acidic conditions for Sudan red?. Then synthesis P-Gly/PtNPs/GR/GCE electrochemical sensing electrode by the adsorption of Graphene to glassy carbon electrode and platinum nanoparticles for the detection of Sudan red? in food. The optimum pH conditions were determined as 3.0 by using cyclic voltammetry. P-Gly/PtNPs/GR/GCE showed good response to Sudan red? with a linear range from 8.0×10-8 mol/L to 2.4×10-6 mol/L and a detection limit of 2.7×10-8 mol/L. The modified electrode showed high stability, selectivity and reproducibility.