Palytoxin Signal in LC-MS and UV: Preliminary Investigation on the Effect of Solvent and Temperature

: Palytoxins (PLTXs) and ovatoxins (OVTXs) are a group of highly potent marine toxins that pose significant health risks through seafood contamination and environmental exposure. OVTX-producing algae have been linked to dermatitis and respiratory distress in Mediterranean beachgoers, while serious public health concerns are related to PLTX accumulation in seafood. In 2009, the European Food Safety Authority highlighted the need for analytical detection methods of the PLTX group of toxins and for the preparation of reference materials. This study investigates the stability of the palytoxin signal using liquid chromatography tandem mass spectrometry (LC-MRM-MS) and UV-Vis spectrophotometry under different experimental conditions: three concentrations (10, 1, and 0.5 µg/mL), three methanol-water mixtures (10%, 50%, and 90%), and two temperatures (6 °C and 25 °C). The results showed that the PLTX signal response is significantly influenced by the experimental conditions used. LC-MRM-MS analysis revealed the optimal response of PLTX in 50% and 90% MeOH at 25 °C, with minimal signal loss occurring over 16 h (9% and 6%). UV-Vis data indicated reduced absorbance in 10% MeOH, but a stable spectral intensity over 21 h in all the tested solvent mixtures. These results underscore the necessity of carefully controlled experimental conditions to ensure accurate and reproducible PLTX detection in environmental and food safety monitoring.