Determination of lipophilic marine toxins in fresh and processed shellfish using modified QuEChERS and ultra-high-performance liquid chromatography–tandem mass spectrometry

A simple QuEChERS method coupled with ultra-high-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was developed to improve the extraction efficiency of lipophilic marine toxins (yessotoxins, dinophysistoxins, okadaic acid, azazspiracids, and spirolides) in fresh and processed shellfish products. The proposed method included freezing and dispersive solid-phase extraction with graphene oxide as the sorbent to clean complex matrices containing lipids (e.g., free fatty acids) and pigments. Quantification was performed using matrix-matched calibration curves. Recoveries were 85%–117.4% and the relative standard deviation for precision was less than 10% for marine toxins in fresh and processed shellfish products. The limits of detection (signal-to-noise = 3) and quantification (signal-to-noise = 10) were 0.10–1.47 and 0.32–4.92 μg/kg, respectively. The validated QuEChERS method, coupled with UPLC–MS/MS, was applied successfully to determine lipophilic marine toxins in fresh and processed shellfish samples.