Multisignal Collaborative Detection of Thiram Based on Dual-Functional Iron-Based Metal Organic Frameworks.

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Thiram (Tr) residues pose risks to food safety and human health.
• Accurate detection methods are crucial for monitoring Tr levels in various matrices.
• Existing methods may lack sensitivity or on-site applicability.

Purpose of the Study:

• To develop a sensitive and reliable dual-mode detection method for thiram (Tr) residues.
• To utilize dual-functional iron-based metal-organic frameworks (Fe-MOFs) for simultaneous fluorescence and colorimetric detection.
• To enable on-site, visual detection of Tr in food and environmental samples.

Main Methods:

• Developed dual-functional Fe-MOFs exhibiting blue fluorescence and peroxidase-like activity.
• Employed Fe-MOF catalyzed oxidation of o-phenylenediamine (OPD) for fluorescence quenching via internal filtration effect (IFE).
• Utilized RGB colorimetric analysis for on-site visualization under UV/sunlight.

Main Results:

• Achieved a low detection limit of 0.18 μM for thiram (Tr), significantly below the MRL of 21 μM.
• Demonstrated effective on-site visualization using the RGB method with observable color changes.
• Validated the method's accuracy and consistency across diverse samples including apples, cabbage, corn, bean sprouts, and soil.

Conclusions:

• The developed ratiometric fluorescence/colorimetric dual-mode method offers a sensitive and accurate approach for thiram (Tr) detection.
• Fe-MOFs provide a versatile platform for developing dual-functional analytical tools.
• The method's ability for on-site detection and cross-verification enhances food safety monitoring and reduces false positives.