Silver nanoparticles-based colorimetric array for the detection of Thiophanate-methyl

Area of Science:

• Nanomaterials Science
• Analytical Chemistry
• Environmental Science

Background:

• Silver nanoparticles (AgNPs) are widely used in chemical sensing due to their unique optical properties.
• Thiophanate-methyl (TM) is a widely used fungicide, and its detection in environmental samples is crucial for monitoring and safety.
• Developing simple, sensitive, and selective sensors for TM is an ongoing challenge in analytical chemistry.

Purpose of the Study:

• To develop a simple and selective colorimetric sensor for the detection of Thiophanate-methyl (TM).
• To investigate the mechanism of interaction between citrate-capped silver nanoparticles (Cit-AgNPs) and TM.
• To evaluate the performance of the developed sensor for TM detection in environmental samples.

Main Methods:

• Synthesis of citrate-capped silver nanoparticles (Cit-AgNPs).
• Colorimetric detection of TM based on the color change of Cit-AgNPs and UV-vis spectroscopy.
• Surface Plasmon Resonance (SPR) band shift analysis.
• Density Functional Theory (DFT) calculations to study TM-citrate interactions.
• Validation of the sensor using environmental samples.

Main Results:

• A color change from yellow to cherry red was observed upon addition of TM to Cit-AgNPs.
• A red-shift in the SPR band from 394 nm to 525 nm was attributed to hydrogen bonding and substitution interactions.
• A linear relationship was found between the absorption ratio (A525nm/A394nm) and TM concentration in the range of 2-100 μM (R² = 0.988).
• The detection limit for TM was determined to be 0.12 μM.
• The sensor demonstrated good recoveries when applied to environmental samples.

Conclusions:

• Cit-AgNPs can serve as a sensitive and selective colorimetric sensor for TM detection.
• The developed method is simple, rapid, and cost-effective for on-site TM monitoring.
• The sensor shows potential for practical application in the analysis of TM in real environmental matrices.