Study Of Rapid Determination Methods For The Food Quality And Safety Based On Nanomaterials

Food safety has become one of the most challenging social issues in China that needs to be addressed. There are loopholes in all the aspects of food chain-from the farm to the table, public concerns over food safety are growing. The traditional methods such as chromatographic methods for the food safety determnation have the merits of high sensitivety and accuracy, but they also suffer from the drawbacks such as time consuming, complexity for sample preparation, high cost for instruments and equipment maintenance,need professional staff and so on. Compared with the traditional methods, the electrochemical methods are proved to be popular tools ascribed to their advantages of stability, selectivity, simple and easy fabrication process, immunoassays are quick, inexpensive, simple to perform, and reasonably portable; they can also be highly sensitive and selective.The study on electrochemical methods and immunoassay for sensitive, rapid, and accurate detection of chemical food and agricultural contaminants is one of the novel and highly attractive research topics.Utilizing the knowledge of different fields, such as nanotechnology, electrochemical methods, immunoassay and magnetic separation technology, different methods were developed for the food safety and quality. A carbon paste electeode based on ionic liquid was developed for the antioxidant epigallocatechin gallate(EGCG) determination in tea infusion, a gold nanoparticle bulk modified ionic liquid carbon paste electrode was constructed for the detection of nitrite in meat products, a carbon nanotube and ionic liquid modified screen printed electrode was developed for the heavy metal ions Pb2+and Cd2+determination in meat products, the competitive immunoassay based on nucleic acid purification system and magnatic separation was used to the detection of clenbuterol in meat products. This study may provide the data support for the electrode preparation and modification in electrochmeical methods. This study may also provide new ideas and theoretical basis for the immunoassay. It has profound effects on developing food safety and quality determination instruments.The main results and conclusions were listed as follows: (1) A carbon paste electeode based on ionic liquid was developed for the antioxidant EGCG determination in tea infusion. The analytical performances of the ILCP electrode are as follows:1) The linear response range is5－10-7-1.25×10-5mol/L and the detection limit is1.32×10-7mol/L.2) The ILCP electeode has the ability of resisting passivation.3) The ILCP electeode has ability of resisting interfering substance.4) The ILCP electrode exhibitted consistency, stability and reproducibility.5) the electeode was used for the detection of EGCG in tea infusion.(2) A new carbon paste electrode modified with gold nanoparticle and based on the use of an ionic liquid as the binder is introduced to the determination of nitrite in bacon samples. The analytical performances of the ILCP electrode are as follows:1) the linear range is1.0×10-4～1.0×10-3mol/L by CV,1.0×10-6-2.0×10-4mol/L by DPV,7.6×10-6～4.4×10-4mol/L by CA,2) the electrode has the capacity of resisting interference,3) The Au NP-ILCP electrode exhibitted consistency, stability, reproducibility.(3) A magnetic beads (MBs) transfer based automated ELISA (MAT-ELISA) was proposed to the detection of clenbuterol (CBL) in meat (pork and pork liver). The results indicated that:1) The diameter of MBs is about509nm,2) The MBs retained good magnetic responsivity after being modification and the MBs can be separated by magnet within1-2s,3) The detection process can be finished within25min, the linear range is0.14～45.5ppb,4) Standard addition methods was employed for the quantitative detection of clenbuterol in real samples.(4) A novel screen printed electrode using nanomaterial and functional material for the determination of heavy metal ions was established. The analytical performance of the electrochemical sensor are as follows:1) the linear range for Pb2+and Cd2+is1.0～100.0ppb,2) The electrochemical sensor exhibited good stability and consistency.3) The electrochemical sensor was used for the analysis and detection of Pb2+and Cd2+in real samples.