Fluorescence Based Study for Melamine Detection Using Gold Colloidal Solutions.

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Materials Science

Background:

• Melamine contamination in food poses significant health risks.
• Developing sensitive and cost-effective detection methods is crucial for food safety.

Purpose of the Study:

• To comparatively study the detection of melamine using different sizes of citrate-capped gold nanoparticles (AuNPs).
• To optimize AuNP size for sensitive and selective melamine detection.
• To evaluate the cost-effectiveness and applicability of the optimized method in real food matrices.

Main Methods:

• Synthesis and characterization of three sizes of gold nanoparticles (15 nm, 30 nm, 40 nm).
• Fluorescence spectroscopy was employed to detect melamine based on AuNP aggregation and fluorescence enhancement.
• Calibration curves were generated to determine the limit of detection (LOD) for each AuNP size.
• Selectivity studies and recovery tests were performed on milk samples.

Main Results:

• All tested AuNP sizes exhibited fluorescence enhancement upon melamine interaction due to aggregation.
• 30 nm AuNPs (AuNPs-II) showed the highest sensitivity with the lowest LOD of 0.66 nM, significantly lower than 15 nm (2.78 nM) and 40 nm (7.74 nM) AuNPs.
• The synthesis of AuNPs-II utilized less HAuCl4, resulting in lower production costs.
• High recovery percentages (94-100%) were achieved for melamine detection in various milk products.

Conclusions:

• Citrate-capped 30 nm gold nanoparticles (AuNPs-II) are optimal for sensitive, cost-effective, and selective detection of melamine.
• The developed fluorescence spectroscopy method using AuNPs-II is a promising tool for melamine analysis in dairy products.