Analysis of domoic acid in shellfish by thin-layer chromatography

Area of Science:

• Analytical Chemistry
• Food Science
• Marine Biology

Background:

• Domoic acid (DA) is a marine biotoxin that can accumulate in shellfish.
• Accurate and accessible detection methods for DA are crucial for public health and food safety.
• Existing analytical methods may require specialized equipment, limiting their widespread use.

Purpose of the Study:

• To develop a simple, semi-quantitative thin-layer chromatography (TLC) method for domoic acid (DA) analysis in shellfish tissues.
• To provide a cost-effective and accessible alternative to instrumental methods for DA screening.

Main Methods:

• Shellfish tissues were extracted using a single-step homogenization with 50% aqueous methanol.
• A selective strong anion exchange cleanup was employed.
• Extracts were analyzed using silica gel TLC plates, developed with a butanol-acetic acid-water mixture.
• Detection was achieved via fluorescence quenching under UV light, with confirmation by ninhydrin staining.

Main Results:

• The TLC method demonstrated a detection limit of 10 microg DA per gram of tissue.
• Fluorescence quenching under UV light allowed for detection, and ninhydrin staining provided distinctive colorimetric confirmation.
• The entire procedure, including extraction, cleanup, and TLC, was found to be fast and simple.

Conclusions:

• The developed TLC method is a rapid, cost-effective, and accessible technique for the semi-quantitative analysis of domoic acid in shellfish.
• This method is suitable for routine screening in laboratories lacking LC systems and can serve as a chemical confirmation tool.