Study On Detection Of AFB1 In Peanut Oil Based On Surface-enhance Raman Spectroscopy Technology

The mycotoxin is a metabolic outcome of the fungi.AFB1,one kind of Aflatoxin,is one of the most prevalent and toxic mycotoxin which often can be found in peanut oil.Therefore,it is very important to quantitative detection of AFB1 by using a rapid,sensitive,simple and efficient detection technology,to ensure the safety of food.In recent years,Surface-enhanced Raman spectroscopy?SERS?,a powerful fingerprint analytical technique,has been widely applied for life sciences,food safety,environmental monitoring,national security and other fields.The detection system is constructed by using nanomaterials with SERS enhancement effect,can realize the rapidly,non-destructively,high sensitivity quantitative detection of target objects.Therefore,we attempt to optimize the SERS substrate materials with good stability and strong enhancement effect,and develop a sensitive detection system to realize the rapid and sensitive detection of AFB1 in peanut oil.The details are concluded as follows:1.Detection of AFB1 based on Au@DTNB@Ag NRs SERS technology.Here,AuNRs were synthesized via seed growth method using CTAB as surfactant.Ascorbic acid?Vc?reduction method of AgNO₃ was used to optimize the appropriate coating thickness of Ag shell outside the AuNRs,DNTB was embedded in Au and Ag core/shell nanorods as Raman reporter molecules.Synthesized AuNR@DNTB@Ag NRs as Raman signal enhancement nanoprobe.Then,synthesized CS-Fe₃O₄ as Raman signal enrichment nanoprobe.The AFB1 aptamer?NH₂-DNA1?and AFB1 complementary aptamer?SH-DNA2?were conjugated to CS-Fe₃O₄ and AuNR@DNTB@Ag NRs respectively,to develop competitive NH₂-DNA1-CS-Fe₃O₄/SH-DNA2-ADANRs detection system.Based on this developed SERS aptasensor,the linear detection ranges from 0.01-100 ng/m L,a low limit of 0.0036 ng/m L and the standard recovery rate from 91.09%to 105.73%for AFB1 detection were obtained with good detection specificity.The study demonstrated the developed detection system can be used for quantitative detection of AFB1 in peanut oil,but the detection limit and linear range remains to be improved.2.Detection of AFB1 based on GNTs@DTNB@Ag@DTNB SERS technology.Here,the GNTs were synthesized with uniform particle size.To optimize the appropriate coating thickness of Ag shell outside the GNTs,the DTNB was labeled on the surface of GTNs and Ag shell as Raman signal molecules.Synthesized GNTs-DTNB@Ag-DTNB?GDADNTs?as Raman signal enhancement nanoprobe and CS-Fe₃O₄ as Raman signal enrichment nanoprobe.The AFB1aptamer?NH₂-DNA1?were conjugated to CS-Fe₃O₄ and GNTs-DTNB@Ag-DTNB respectively,to develop sandwich GNTs@DTNB@Ag@DTNB-aptamer/aptamer-CS-Fe₃O₄ detection system.Based on this developed SERS aptasensor,the linear detection ranges from 0.001 to 100000ng/m L,a low limit of 0.00054 ng/mL,the standard recovery rate from 94.70%to 109.00%for AFB1 detection were obtained with good detection specificity.The study demonstrated the developed detection system can be used for quantitative detection of AFB1 in peanut oil with better detection limit and linear range.3.Detection of AFB1 based on AgMNPs SERS technology.Here,the AgMNPs Raman enhancement nanomaterials were fabricated using EP-FDU-12 as a template,and ethylene glycol as an organic reducing agent.Using synthesized AgMNPs blended with different concentrations of AFB1,collect its SERS spectra.The density functional theory?DFT?was applied to calculate the theoretical Raman peak and compare it with the SERS Raman peak of AFB1 to determine the characteristic Raman peaks of AFB1.The multivariate calibration methods?PLS and BP-AdaBoost?were applied for data modeling to quantify AFB1 using the selected Raman characteristic peaks respectively.The results showed that the BP-AdaBoost obtain the optimum result with a high determination coefficient in the prediction set?Rp?=0.9283 with a linear range from 5 to 100 ng/m L,and Rp=0.9332 with a linear range from 100 to 1000 ng/mL,a decent reproducibility and higher stability with RSD of ca.5%.The overall results demonstrated that developed detection method is rapid and accurate,which can be extended to fast quantitative detection of AFB1 in peanut oil.