Challenges in phycotoxin analysis in marine mammal biological matrices

ARREGUI, MARINA; D'AGOSTINO, VALERIA C.; DEGRATI, MARIANA; JAN TEBBEN; KROCK, BERND

Hiroshima

Congreso; 20th International Conference on Harmful Algae; 2023

Marine mammals (MMs) have great potential as sentinel species to assess the effect ofharmful algal blooms (HABs) on the marine ecosystem and public health. Despite this,phycotoxin exposure of MMs remains largely unknown worldwide. Moreover, working withMM tissues and fluids is often challenging due to their complex matrices, the limited sampleavailability, and the lack of standardized protocol for phycotoxin analysis by liquidchromatography coupled to post-column derivatization and fluorescence detection (HPLC-FLD) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS).Currently, most of the scarce studies published do not accurately assess the matrix effect (ME)and its role in ion suppression or enhancement in LC-MS/MS. Considering all the above, thepresent study aimed to select suitable extraction methods to minimize MEs. Different clean-up steps were tested, including hexane washing, protein precipitation, and lipid freezing. Mostof the latest work has focused on solid phase extraction (SPE), carrying out different types ofSPE (normal, reverse and ion exchange phases) and various cartridge sorbents. So far, resultsshow that the ME is highly dependent on the tissue analyzed. Also, the techniques tried haveproven inefficient in significantly reducing the ME and achieving good recoveries for thevarious phycotoxin classes assessed. In the following months, mixed-mode SPE phases andmatrix-matched calibration curves for each type of tissue or fluid will be explored tocompensate for ME.