Laser fluorometric determination of aflatoxin B1 in corn

Area of Science:

• Food Science
• Analytical Chemistry
• Biochemistry

Background:

• Aflatoxins are toxic fungal metabolites that contaminate food crops like corn.
• Accurate detection of aflatoxin contamination is crucial for food safety and regulatory compliance.
• Existing methods may lack the sensitivity required for very low contamination levels.

Purpose of the Study:

• To develop a highly sensitive method for detecting aflatoxin B1 in corn.
• To achieve detection limits of 0.1 ppb (microgram/kg) for aflatoxin contamination.
• To validate the method's accuracy and efficiency in complex matrices.

Main Methods:

• A two-step chromatographic separation involving thin-layer chromatography (TLC) and high-pressure liquid chromatography (HPLC).
• Extraction of aflatoxin B1 from corn using a water-methanol solvent system.
• Conversion of aflatoxin B1 to a more fluorescent derivative (B2A) for enhanced detection.
• Detection using laser fluorometry with a He-Cd ion laser and a lock-in amplifier.

Main Results:

• Achieved a detection limit of 0.1 ppb (microgram/kg) for aflatoxin B1 in corn.
• Demonstrated a root mean square variation of 26% for the method.
• Showed linear recovery of aflatoxin from TLC plates between 10 and 1000 pg.
• Confirmed consistent conversion to the B2A derivative over three orders of magnitude of B1 concentration.
• Chromatograms illustrated effective removal of interfering compounds from corn extracts.

Conclusions:

• The developed 2-step chromatographic and laser fluorometric method provides sensitive and reliable detection of aflatoxin B1 in corn.
• This technique significantly extends the detection capabilities for aflatoxin contamination in food matrices.
• The method's ability to handle interfering components makes it suitable for routine analysis.