CN-116858803-B - Aflatoxin qualitative detection method based on terahertz metamaterial absorber

Abstract

The invention discloses an aflatoxin qualitative detection method based on a terahertz metamaterial absorber, wherein the period P of the terahertz metamaterial absorber is 60 mu m, a coating metal is gold, a silicon substrate is adopted, the terahertz metamaterial absorber comprises a large cross structure positioned at the middle position and a plurality of small cross structures positioned around the large cross structure, the length L1 of the large cross structure is 30 mu m, the width W of the large cross structure is 2 mu m, the small cross structure comprises a cross-shaped main body part and an outer frame part arranged on the outer side of the main body part, the main body part is perpendicular to the outer frame part, the length L2 of the main body part is 25 mu m, the length L3 of the outer frame part is 12 mu m, and the distance d between one side of the large cross structure and the center of the main body part is 15 mu m. The invention develops a novel metamaterial, realizes qualitative detection of aflatoxin by using the metamaterial, and provides a novel approach for qualitative detection of aflatoxin.

Inventors

• HU JUN
• ZHAN CHAOHUI
• XU SIJIE
• OUYANG AIGUO
• HE YONG

Assignees

• 华东交通大学

Dates

Publication Date

20260512

Application Date

20230706

Claims (1)

1. 1. The terahertz metamaterial absorber is characterized by comprising a large cross-shaped structure positioned at the middle position and a plurality of small cross-shaped structures positioned at the periphery of the large cross-shaped structure, wherein the length L1 of the large cross-shaped structure is 30 mu m, the width W of the large cross-shaped structure is 2 mu m, the small cross-shaped structure comprises a cross-shaped main body part and an outer frame part arranged on the outer side of the main body part, the main body part is perpendicular to the outer frame part, the length L2 of the main body part is 25 mu m, the length L3 of the outer frame part is 12 mu m, and the distance d between one side of the large cross-shaped structure and the center of the main body part is 15 mu m; the terahertz metamaterial absorber is prepared by the following preparation method: The method comprises the steps of processing a four-inch double polished silicon wafer and a glass wafer, wherein the whole processing technology comprises film plating, pretreatment, photoresist homogenizing, pre-baking, exposure, development, photoresist beating, film hardening, etching and stripping, firstly plating 5nm of chromium on a silicon substrate, then plating 100 nm of gold, after metal deposition, adopting an HMDS oven for pretreatment, wherein the temperature of the oven is set to 120 ℃ for 10min, conducting photoresist homogenizing after pretreatment, dripping photoresist AZ6112 on the surface of the silicon substrate, adopting a photoresist homogenizing machine to rotate at 600r, spreading the photoresist AZ6112 dripped on the surface of the silicon substrate, then conducting uniform film forming at 4000r, reaching the thickness of 1-2 mu m, conducting pre-baking after the photoresist homogenizing, conducting manual development for 35s at the temperature and time of 100 ℃ respectively, conducting exposure after the pre-baking, conducting photoresist removing by adopting a photoresist removing machine after the exposure, setting power of the photoresist homogenizing machine to be set to be 200 ℃, etching for 3 ℃ for complete etching by adopting a microscope, namely, and finally conducting ultrasonic etching for complete etching for a film forming after the film is completely reaching the film forming, and completely removing the film after the film is completely removed by adopting a mask, and finally conducting ultrasonic etching for 120s, and completely removing the film after the film is completely etched by adopting a mask for the film forming after the film is completely etched for 1m, and the film forming is completely removed by adopting a mask is completely removed, and the film is completely removed by adopting a mask after the film is completely etched for a film after the film is completely removed.

Description

Aflatoxin qualitative detection method based on terahertz metamaterial absorber Technical Field The invention relates to the technical field of chemical detection, in particular to an aflatoxin qualitative detection method based on a terahertz metamaterial absorber. Background Food safety concerns are related to social stability and people's daily lives. Among the food safety problems, the food safety problem of aflatoxin contamination has become a global problem. Aflatoxins (AFs) are a group of harmful mycotoxins produced by aspergillus flavus that can contaminate both water and food products. Aflatoxins have been reported to cause hepatocellular carcinoma, rayleigh syndrome and chronic hepatitis, causing serious harm to the human body. The derivatives have more than 20 kinds, and the main types of more common and relatively high toxicity are aflatoxin B1 (AFB 1), aflatoxin B2 (AFB 2), aflatoxin G1 (AFG 1) and aflatoxin G2 (AFG 2). In 1993, aflatoxins were listed as class I carcinogens by the world health organization cancer research institute, and these extremely toxic carcinogens primarily contaminate agricultural products such as peanuts, corn, and grains, causing them to mold and spoil. People can cause pathological changes of cells in bodies by eating agricultural products and foods polluted by aflatoxin by mistake, so that the physical health of people is seriously endangered. In order to solve the pollution of aflatoxin to agricultural products and foods, strict regulatory control has been implemented on the aflatoxin content in agricultural products and foods in many countries. Wherein the U.S. federal government regulations prescribe that the aflatoxin content (referred to as the total amount of B1+B2+G1+G2) in human-consumed foods and dairy feeds should not exceed 15 μg/kg, that the content in human-consumed milk should not exceed 0.5 μg/kg, and that the content in other animal feeds should not be 300 μg/kg. The EU state specifies more stringent peanut and nut and processed products and all cereal and processed products with an aflatoxin B1 limit of 2.0 μg/kg, raw milk, heat treated milk and processed milk products with an M1 limit of 0.050 μg/kg, infant formula (including infant formula) with an M1 limit of 0.025 μg/kg. In order to prevent aflatoxin from polluting foods, related standards and management methods have been put out in China related departments to strictly limit the content of aflatoxin in different foods. At present, common physicochemical analysis methods for detecting aflatoxin at home and abroad comprise thin layer chromatography, high performance liquid chromatography, enzyme-linked immunosorbent assay, electrochemical method and the like. Although the physicochemical analysis methods have higher detection sensitivity to aflatoxin, the method has the defects of high detection cost, long detection period, poor experimental repeatability, complex and tedious experimental process, damage to experimental samples and the like. In recent years, many scholars have also sought spectroscopic detection techniques for qualitative and quantitative analysis of aflatoxin in foods, mainly including spectroscopic detection techniques such as near infrared Spectroscopy (NIR), fluorescence Spectroscopy (Fluorescence Spectroscopy), raman Spectroscopy (RAMAN SPECTRA) and multispectral techniques. However, although the near infrared spectroscopy has the advantages of high efficiency, no damage and the like, the quantitative detection of aflatoxin can be realized, but the accuracy and the sensitivity of quantitative analysis of aflatoxin still have the defects, and the international requirements cannot be met. The fluorescence spectrum technology has the characteristics of high analysis speed, high analysis precision and the like, but has a plurality of interfered factors. Although SERS enhancement can be adopted in Raman spectrum, the enhancement conditions are very severe, and the selection and preparation of an enhanced substrate are difficult. Therefore, finding a rapid, nondestructive and high-sensitivity detection method for trace aflatoxin in food is always a focus of great concern in the field of food safety and a focus of research of domestic and foreign scholars. Terahertz (Terahertz, THz) waves generally refer to electromagnetic waves having a frequency in the range of 0.1 to 10 THz. The terahertz spectrum technology has the advantages of small photon energy, high resolution, rich optical parameters and the like, and provides a theoretical basis for the application of the terahertz spectrum technology to biological and chemical molecular detection. In recent years, expert students have developed related researches in the fields of biology, chemical molecules and the like by using terahertz spectrum technology. However, with the intensive research, the difficulty coefficient of detecting trace substances with higher toxicity and larger harm by using the traditional terahertz spectrum detec