Study On The Detection Of Morphine In Hotpot Seasoning Based On Molecular Imprinting

The illegal additives for non-food processing brings serious risks to food safety.Opium poppy shell mainly contains morphine,codeine and other alkaloids,which will cause harm to the body if eaten for a long time.Therefore,Opium poppy shell is one of non-food additives prohibited by the state.However,some illegal businesses add them to food seasoning soups（such as hotpot soup base）for economic benefits,which will cause potential harm to the health of consumers.Therefore,it is necessary to establish a fast,simple and accurate detection method for poppy shell added in food.It can also be used as a convenient tools for on-site screening of poppy shell added illegally in hot pot soup base.In this paper,morphine,as one of characteristic alkaloids in poppy shell,was used as the detection object.The imprinted recognition products of morphine were prepared by molecular imprinting on the surface of quantum dots and protein carrier imprinting technology.The main researches are as follows:1.CdTe/SiO₂ QDs as fluorescent base material for imprinted polymers were prepared.Using MPA as the Cd²⁺ligand and TEOS as modifier of the SiO₂,water-soluble CdTe/SiO₂QDs were synthesized in a“one-step”method.The optimum synthesis conditions were determined as follows:the molar ratio of Cd²⁺:Te:TEOS was 2:1:100,the reaction time of reflux reaction was 3 h,and the reaction temperature was 100℃.The synthesized CdTe/SiO₂QDs were characterized by transmission electron microscopy（TEM）and Fourier infrared spectroscopy（FT-IR）.The results showed that water-soluble CdTe/SiO₂ QDs with uniform particle size,excellent optical performance and stability.The excitation wavelength is 350 nm and the emission wavelength is 538 nm.The surface silanized QDs with better modifiability are safer and more stable than the bare CdTe QDs.2.Preparation of molecularly imprinted polymers based on CdTe/SiO₂ QDs.Using CdTe/SiO₂ as supports,morphine base as the template molecule,3-aminopropyltriethoxysilane（APTES）as the functional monomer,and ethyl orthosilicate（TEOS）as the cross-linker,respectively.CdTe/SiO₂@MIPs were prepared by the“sol-gel”method and be used for the detection of morphine in the bottom of hot pot.The detection linear range is 0.2²0 mg/L,the minimum detection limit is 0.114 mg/L,and the recovery rate is 79.43⁸6.27%.Compared with the bulk polymerization of CdTe@MIP,this surface sol-gel polymerization of CdTe/SiO₂@MIPs has the advantages of uniform distribution of imprinting sites,rapid and effective adsorption equilibrium,excelent selectivity and stability.3.A strategy to design a biomimetic immunoassay based on imprinted proteins（IPs-BELISA）for the detection of morphine has been proposed.Proteins were used as scaffolds for generation of binding cavities with high specificity against morphine.Different proteins（BSA and OVA）and template molecules（free morphine base and6-succinyl-morphine）were tested.For IPs-BELISA,the imprinted proteins were primarily prepared in a tube and immobilized on micro-well plate as the substitute of biological antibody.The results demonstrate the ability to generate specific interactions to morphine with a linear relation between signals and log concentration of the target morphine in the range of 0.00625to 0.1mg/L（R²=0.9822）,and the detection limit was 0.003 mg/L.For recovery analysis,the concentrations of morphine in the spiked hot pot soup base were determined by the developed IPs-BELISA.The recoveries of morphine were between 70.9%and 85.5%.Compared with the biological antibodies-based ELISA（Abs-ELISA）,the imprinted protein-based biomimetric ELISA can also achieve the efficient detection of morphine.