High Sensitive Detection Of Melamine Based On Molecular Imprinting And Fluorescence Probe

Food safety has been closely related to people's life,which has a direct impact on the health of human life and the development of social and economic stability.In the year of 2008,the event of melamine-tainted infant formula milk powder making baby kidney stone occurred in the domestic,and led to the detection of melamine become a hot spot of concern.Therefore,the development of efficient and rapid quantitative technology to detect illegal additive of melamine residue in milk has been as the key to effectively solve the current security issues.Molecular imprinting technique is a technique that can be used to prepare polymers with a specific binding ability to the target molecule,and this kind of polymers has good stability and high selectivity to the target,so this technology has been used widely in the food safety analysis.Because of its high specificity,high sensitivity,real-time and fast analysis,fluorescent chemical sensors have gradually become an ideal method for the detection of various metal cations,small molecules,biological active substances and some anions.In this experiment,a special recognition performance and high binding capacity of melamine-MIPs were prepared,and MIPs also achieved good enrichment effect,and the fluorescent chemical sensor of Rhodamine glyoxal Acylhydrazones synthesized by Rhodamine B was used for the quantitative detection of melamine.In combination with the advantages of these two methods,a high sensitivity and quantitative method for the determination of melamine residues in milk samples was established.The research results were as follows:(1):Using precipitation polymerization method,the molecular imprinted polymers with specific recognition ability and high capacity binding properties were prepared by optimizing the molar ratio of template molecule and functional monomer and the volume ratio of composite solvent,and imprinted factor was 3.072.The optimal preparation conditions were as follows:0.3 mmol(37.8g)of melamine was used as a template molecule,and 2 mg of nano-CaCO3 was used as porogenic agent,and 60 mL of acetonitrile mixed with methanol solution(10/50,V/V)was used as solvent,and 3.6 mmol(0.3 mL)of methacrylic acid was used as functional monomer,and 26.5 mmol(5 mL)of ethyleneglycoldimethacrylate was used as crosslinking agent and 30 mg of azobisisobutyronitrile was used as initiator.After ultrasonic degassed 15 min and purged with nitrogen gas for 15 min,the above pre-polymerization system was sealed and placed in the water-bath at 60 ? for 24h.(2):Quantitative detection of melamine could be detected by fluorescent chemical sensor of RBI synthetized with rhodamine B through two-step method.When we choose the maximum excitation wavelength at 530 nm,the maximum emission peak appeared at 590 nm.With the increase of the concentration of melamine solution,the fluorescence intensity increased,and showed a good linear relationship.The detection line of melamine was 1.55 × 10-4 mmol/L,and linear range was 6.25 × 10-1-8 ×10-2 mmol/L,and relative standard deviation was from 3.18 to 4.91%.In this experiment,molecular imprinting polymers were used to enrich melamine and melamine was next detected by fluorescent chemical sensor,therefore a new method of detecting melamine in milk was established.