A Sensitive LC-MS/MS Method for Palytoxin Using Lithium Cationization

Area of Science:

• Marine Biology
• Analytical Chemistry
• Food Safety

Background:

• Palytoxin (PlTX) and its analogues are potent marine toxins produced by various marine organisms.
• These toxins can accumulate in the food chain, posing a significant risk to human health through seafood consumption.
• Existing analytical methods for PlTX are often complex and lack sensitivity due to the toxin's large molecular structure.

Purpose of the Study:

• To develop a sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of palytoxins (PlTXs).
• To optimize sample preparation and chromatographic conditions for accurate PlTX detection in shellfish matrices.
• To validate the developed method for routine food safety monitoring.

Main Methods:

• Development of an LC-MS/MS method utilizing lithium iodine and formic acid as mobile phase additives.
• High-resolution mass spectrometry (LC-hrMS) was employed for elemental composition determination and fragment identification.
• Optimization of a solid-phase extraction (SPE) clean-up procedure for shellfish samples.

Main Results:

• A 10-minute LC-MS/MS method was established, identifying the main adduct as [M + H + 2Li]³⁺.
• Method achieved limits of detection of 8 µg PlTX kg^-1 in mussels and 22 µg PlTX kg^-1 in oysters.
• In-house validation demonstrated good repeatability (RSD < 20%) for PlTX analysis in various shellfish.

Conclusions:

• The developed LC-MS/MS method provides a sensitive and selective approach for palytoxin analysis in shellfish.
• The method's validation supports its application in routine monitoring and ensuring seafood safety.
• Further optimization for oyster matrices may be needed due to observed lower recovery rates.