| In order to continuously improve the limits of mycotoxins and pollutants in food in China,it is of great significance to develop reliable and sensitive detection methods and efficient removal strategies for mycotoxins to ensure food security and public health.Persistent luminescent nanoparticles have unique afterglow luminescence properties,which can effectively avoid the interference of spontaneous fluorescence and scattered light from complex matrices and biological samples,and are of great significance for improving detection sensitivity and accuracy.The purpose of this paper is to develop persistent luminescent nanoparticles with pH response,ratio,bicolor and continuous photocatalysis,and to establish a variety of highly selective and sensitive analytical methods in combination with enzymelinked immunosorbent assay,magnetic separation,aptamer recognition and photocatalysis degradation strategies,which can be used for rapid detection and degradation removal of mycotoxins.The specific content of the paper includes the following four parts:(1)Zn2GeO4:Mn2+,Eu2+(ZGME)persistent luminescent nanoparticles with adjustable morphology,size and luminescent properties were prepared by hydrothermal synthesis.Using the excellent afterglow luminescence characteristics and interesting characteristics of pH stimulation response of ZGME,a non fluorescent interference signal probe was constructed.By combining with pH regulation mediated by enzyme catalytic reaction,a stimulating competitive enzyme-linked immunosorbent assay(ELISA)signal was realized for the detection of ochratoxin A(OTA).Under the optimal immune response conditions,there is a good linear relationship between the change in ZGME luminescent intensity at 535 nm and the concentration of OTA in the range of 0.1 jig L-1 to 63 pg L-1,with a detection limit of 0.045 μg L-1 is 13 times better than the detection limit of commercial ELISA method(0.74 μg L-1).The constructed competitive ELISA method was used for the detection of OTA content in grain samples,with spiked recoveries ranging from 81.3%to 94.4%and relative standard deviation(RSD)less than 4.2%(n=5).Further research indicates that pH responsive persistent luminescence ZGME is expected to be used in advanced information encryption and anti-counterfeiting fields.This work has developed persistent luminescent nanoparticles with intrinsic responsive luminescence,which can effectively eliminate the interference of background signals and provide a new method for reliable and sensitive detection of OTA content in samples from different fields.(2)Persistent luminescence nanoparticles ZnGa2O4:Mn2+,Cr3+,In3+ with regular morphology,uniform particle size,and good luminescent performance were prepared by a hydrothermal method and high-temperature calcination.An analytical method for the determination of ochratoxin A(OTA)using a ratio probe based on Mn2+/Cr3+ co-doped ZnGa2O4 dual wavelength luminescence nanoparticles was established with the luminescent at 510 nm and 704 nm as reference and response signals,respectively.Under optimal conditions,the established method for the determination of OTA has a linear range of 0.005 ng mL-1 to 100 ng mL-1,Δ(I704/I510)has a good linear relationship with the logarithmic concentration of OTA,with a detection limit of 1.8 ng L-1.The established method was used for the detection of OTA in different samples(grains,beer),with recoveries ranging from 92.5%to 103.7%and RSD less than 4.4%(n=5).In this work,a ratio probe of double wavelength persistent luminescence nanoparticles was developed,which provides a new idea for rapid and highly sensitive detection of ochratoxin A in complex samples.(3)Zn2GeO4:Mn2+(ZGM),Zn1.25Ga1.5Ge0.25O4:Cr3+,Yb3+,Er3+(ZGGOC)bicolor persistent luminescence nanoparticles with regular morphology,uniform particle size,and good luminescent performance were synthesized by hydrothermal reaction under optimal conditions.To construct a detection system of functional two-color persistent luminescence nanoparticles combined with functional magnetic separation for simultaneous detection of ochratoxin A(OTA)and aflatoxin B1(AFB1).In this method,two persistent luminescence nanoparticles with emission wavelengths of 535 nm and 700 nm are used as signal units,and aptamers with high specificity and affinity corresponding to mycotoxins are used as recognition units.The aptamer modified persistent luminescence nanoparticles and the aptamer complementary chain modified Fe3O4 magnetic nanoparticles are used to prepare detection probes through DNA hybridization.The change of the luminous intensity of bicolor persistent luminescence nanoparticles showed a good linear relationship with the concentration of AFB1 and OTA in the range of 0.001～50 ng mL-1,and the detection limits were 0.34 and 0.37 ng L-1,respectively.This method has been successfully applied to the simultaneous determination of AFB1 and OTA in grain samples,with spiked recoveries of 93.6%～103.4%and 93.8%～104.2%,respectively,and RSDs less than 4.0%and 5.2%.This method provides a new idea of high sensitivity,high selectivity and low background interference for simultaneous detection of multi-component mycotoxins.(4)A new type of visible light driven double Z-type Sr2MgSi2O7:Eu2+,Dy3+(SMS)/BiVO4/NH2UiO-66(SBN)composite photocatalyst was successfully prepared by solvothermal method,and the efficient and sustainable degradation of methylene blue and mycotoxins was achieved.persistent luminescence nanoparticles Sr2MgSi2O7:Eu2+,Dy3+and visible light responsive BiVO4 semiconductors were anchored on based zirconium metal organic framework NH2-UiO-66 as a carrier.The constructed ternary composite photocatalytic material can still maintain photocatalytic activity even after the light source disappears.Under light(1 hour)-dark(4 hours)conditions,the degradation rate of methylene blue by SMS/BiVO4/SBN material increased from 76.3%to 89.23%.This enhanced and sustained photocatalysis mechanism is attributed to the formation of heterojunction,especially the incorporation of persistent luminescence nanoparticles,which has constructed the switch of double Z-type electron transfer pathway.It helpful for electron transfer and storage in the light phase,and then release electrons in the dark phase.At the same time,the photocatalysis activity of composite materials is continuously enhanced under the light and dark conditions.The application research shows that the photocatalytic degradation performance of SMS/BiVO4/SBN photocatalyst for mycotoxins AFB1 and OTA is very good,and the degradation rates are 83.9%and 78.1%respectively.This research successfully developed the SMS/BiVO4/SBN composite photocatalyst material based on persistent luminescence nanoparticles,which is expected to be used for the oxidative removal of organic pollutants and mycotoxins in a natural day and night cycle. |
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