Stability of aflatoxins in solution.

Area of Science:

• Mycology
• Analytical Chemistry
• Food Safety

Background:

• Aflatoxins are toxic secondary metabolites produced by Aspergillus fungi.
• Accurate quantification of aflatoxins is crucial for food safety and regulatory compliance.
• Aflatoxin instability in solution can lead to inaccurate analytical results.

Purpose of the Study:

• To investigate the stability of aflatoxins B1, B2, G1, and G2 under various storage conditions.
• To determine optimal solvent compositions and temperatures for aflatoxin standard solutions.
• To evaluate the impact of autosampler vial surface treatments on aflatoxin stability.

Main Methods:

• Aflatoxin solutions (B1, B2, G1, G2) were prepared with varying concentrations of water, acetonitrile, and methanol.
• Stability was assessed at room temperature (20°C) and refrigerated conditions (5°C).
• Aflatoxin degradation was monitored in standard and treated autosampler vials (nitric acid, silanized).

Main Results:

• Aflatoxins G1 and G2 degraded in aqueous solutions at 20°C, requiring 100% organic solvent for stability.
• Aflatoxins B1 and B2 showed stability in methanol-water (>60% organic) and acetonitrile-water (>40% organic) at 20°C.
• At 5°C, significant degradation of G1 and G2 occurred below 20% organic solvent.
• Standard amber vials caused significant aflatoxin loss, while nitric acid or silanized treatments prevented degradation.

Conclusions:

• Aflatoxins exhibit instability in aqueous solutions, necessitating careful handling and storage.
• Optimal stability is achieved with higher organic solvent concentrations (≥20%), refrigeration (5°C), and treated autosampler vials.
• These findings are critical for ensuring the accuracy of aflatoxin analysis in food and agricultural products.