Screening for multiple classes of marine biotoxins by liquid chromatography–high-resolution mass spectrometry

Abstract

Marine biotoxins pose a significant food safety risk when bioaccumulated in shellfish, and adequate testing for biotoxins in shellfish is required to ensure public safety and long-term viability of commercial shellfish markets. This report describes the use of a benchtop Orbitrap system for liquid chromatography-mass spectrometry (LC-MS) screening of multiple classes of biotoxins commonly found in shellfish. Lipophilic toxins such as dinophysistoxins, pectenotoxins, and azaspiracids were separated by reversed phase LC in less than 7min prior to MS data acquisition at 2Hz with alternating positive and negative scans. This approach resulted in mass accuracy for analytes detected in positive mode (gymnodimine, 13-desmethyl spirolide C, pectenotoxin-2, and azaspiracid-1, -2, and -3) of less than 1ppm, while those analytes detected in negative mode (yessotoxin, okadaic acid, and dinophysistoxin-1 and -2) exhibited mass errors between 2 and 4ppm. Hydrophilic toxins such as domoic acid, saxitoxin, and gonyautoxins were separated by hydrophilic interaction LC (HILIC) in less than 4min, and MS data was collected at 1Hz in positive mode, yielding mass accuracy of less than 1ppm error at a resolving power of 100,000 for the analytes studied (m/z 300-500). Data were processed by extracting 5ppm mass windows centered around the calculated masses of the analytes. Limits of detection (LOD) for the lipophilic toxins ranged from 0.041 to 0.10μg/L (parts per billion) for the positive ions, 1.6-5.1μg/L for those detected in negative mode, while the domoic acid and paralytic shellfish toxins yielded LODs ranging from 3.4 to 14μg/L. Toxins were detected in mussel tissue extracts free of interference in all cases.