Oil-phase And Water-phase Food Analysis Based On The Optical Properties Of Semiconductor Nanomaterials

As the key link in ensuring food safety,food inspection is of great significance to promote economic development and protect human life safety.Specific detection probes ought to be developed to meet the detection requirements of different food matrices.Detection probes with simple pretreatment,stable detection results and suitable for oil-phase detection are more suitable for detection of oil-phase food matrix.In the water-phase system,the high signal intensity,anti-interference,accurate and sensitive detection probes are applicable to the detection of water-phase food matrix.The all-inorganic perovskite quantum dots exhibit stable fluorescence properties in oil-phase matrix,and the persistent luminescence nanoparticles are able to avoid the interference of water-phase matrix due to the afterglow properties.Thus,in this paper,semiconductor nanomaterials,such as all-inorganic perovskite quantum dots(Cs Pb X₃ QDs)and persistent luminescence nanoparticles(PLNPs),are studied as the research objects.Fluorescent probes,SERS biosensors and fluorescence-SERS dual-modal biosensors are designed to realize sensitive and accurate analysis of harmful factors in edible oil and food-borne pathogenic enterotoxins(Staphylococcal enterotoxins,SEC)in water phase.The main works of this paper are listed as follows:1.Based on all-inorganic perovskite nanomaterials,multiplex-mode fluorescence sensing of edible oil quality detection method was constructed.A series of Cs Pb X₃ QDs with different emission were prepared by adjusting the feed ratio of lead halide and reaction time.The orange fluorescence intensity of oil-soluble Cs Pb Br_1.5I_1.5 QDs remained stable in edible oil.Based on the principle that the perovskite structure of Cs Pb Br_1.5I_1.5 QDs was destroyed and the fluorescence was quenched when encountering acid,the“turn-off”fluorescence sensors were designed for detecting acid value in edible oil,and the limit of detection(LOD)was 0.71 mg KOH/g.Besides,since halogen exchange was conducted easily between 3-chloro-1,2-propanediol(3-MCPD)and Cs Pb Br_1.5I_1.5 QDs in toluene,“wavelength-shift”fluorescence sensors were designed for detecting 3-MCPD in edible oil.The LOD of 3-MCPD was 39.81?g/m L.In addition,based on the mesoporous silica coated all-inorganic perovskite quantum dots(Cs Pb Br_1.5I_1.5@MSNs)and water-stable two-dimensional perovskite nanosheet Cs Pb Br₃NSs,the ratiometric fluorescent probes were constructed for detecting moisture content in edible oil(LOD=0.45%).A series of perovskite nanomaterials with different properties were prepared to realize convenient,sensitive and naked-eye detection of harmful factors in edible oil,which also provided new materials and novel approaches for the multiplex-mode oil-phase food safety monitoring.2.The SERS biosensors based on all-inorganic perovskite nanomaterials were constructed for SEC detection in water-phase food matrix.The green-emitting Cs Pb Br₃@MSNs were prepared by the high-temperature solvent removal method,which transformed into non-fluorescent Cs Pb₂Br₅@MSNs semiconductor nanomaterials when exposed to water.MSNs enabled the Cs Pb₂Br₅@MSNs to be uniformly dispersed in water and provided reaction sites for the modification of biomolecules.The SERS biosensors based on the composites of Cs Pb₂Br₅@MSNs and Au-Ag Janus NPs exhibited enhanced SERS signal.The constructed SERS biosensor could realize the sensitive detection of SEC in actual milk samples,and the detection limit was 0.83 pg/m L.3.Based on the composites composed of persistent luminescence nanoparticles and plasmonic nanomaterials,the fluorescence-SERS dual-modal biosensors were developed for sensitive and accurate detection of SEC in water-phase matrix.The red-emitting persistent luminescence nanoparticles(ZGGO NPs)were synthesized by hydrothermal method,which were assembled with the plasmonic nanomaterial Au NBPs into SEC-composites through SEC antibody/antigen.Based on plasmon-enhanced fluorescence mechanism and the mechanism of the unique phonon-assisted upconversion photoluminesce(PA-UCPL)of ZGGO NPs enhanced SERS,SEC-composites displayed enhanced fluorescence signal and SERS signal.The developed fluorescence-SERS dual-modal optical biosensors provided two independent detection signals that can be mutually verified,the LODs for PL signal and SERS signal were7.5 pg/m L and 8.9 pg/m L respectively,which further improved the accuracy of SEC detection.The construction of dual optical signal sensors could avoid the interference of food matrix and effectively improve the reliability of SEC detection.