Determination of Cyanotoxins and Phycotoxins in Seawater and Algae-Based Food Supplements Using Ionic Liquids and Liquid Chromatography with Time-Of-Flight Mass Spectrometry

Abstract

An analytical procedure is proposed for determining three cyanotoxins (microcystin RR, microcystin LR, and nodularin) and two phycotoxins (domoic and okadaic acids) in seawater and algae-based food supplements. The toxins were first isolated by a salting out liquid extraction procedure. Since the concentration expected in the samples was very low, a dispersive liquid–liquid microextraction procedure was included for preconcentration. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate (80 mg) was used as green extractant solvent and acetonitrile as disperser solvent (0.5 mL) for a 10 mL sample volume at pH 1.5, following the principles of green analytical chemistry. Liquid chromatography with electrospray ionization and quadrupole time of flight-mass spectrometry (LC-Q-TOF-MS) was used. The selectivity of the detection system, based on accurate mass measurements, allowed the toxins to be unequivocally identified. Mass spectra for quadrupole time of flight-mass spectrometry (Q-TOF-MS) and Q-TOF-MS/MS were recorded in the positive ion mode and quantification was based on the protonated molecule. Retention times ranged between 6.2 and 18.3 min using a mobile phase composed by a mixture of methanol and formic acid (0.1%). None of the target toxins were detected in any of the seawater samples analyzed, above their corresponding detection limits. However, microcystin LR was detected in the blue green alga sample.

Co-Occurrence of Cyanobacteria and Cyanotoxins with Other Environmental Health Hazards: Impacts and Implications

“…Following wildlife-, domestic animal-, and human-intoxications due to exposure to cyanobacterial mass populations, the volume of research over recent years into the toxicology and toxinology of cyanobacteria and cyanotoxins has increased greatly and such growth continues e.g., [ 1 , 5 , 7 , 8 ]. In recognition of the co-occurrence of multiple variants within individual classes of cyanotoxins, of different cyanotoxin classes, and of cyanotoxins plus phycotoxins, it is encouraging that physico-chemical methods for the co-analysis of these combinations are being developed [ 5 , 19 , 20 , 21 , 140 ]. However, since cyanobacterial mass populations commonly develop in waterbodies which are under intensive anthropogenic use (e.g., for domestic, industrial, and agricultural wastewater discharge, abstraction for drinking water treatment, recreation, crop irrigation, and fisheries) it should be anticipated that toxigenic cyanobacteria can co-occur with a wide range of additional biological and chemical health hazards.…”

“…The further development and application of physico-chemical analytical methods for the detection, identification, and quantification of specific cyanotoxins continues to support and enable the application of policies for the risk management of water resources affected by cyanobacterial mass populations. These include specific methods for individual classes of cyanotoxins [ 5 ] and, increasingly, methods for the multiclass analysis of the toxins in single procedures [ 18 , 19 , 20 , 21 ]. However, whilst such methods alone can provide a partial indication of toxicity presented by axenic strains of cyanobacteria grown in the laboratory, they may not take into full account the toxicological significance of mass populations of cyanobacteria in open environments.…”

“…In marine and freshwater environments and in terrestrial and aerial habitats, whilst cyanobacteria can readily appear as “dominant”, i.e., to account for the majority of the microbial biomass, they can be accompanied by a wide range of other microbes including microalgae, chemoheterotrophic bacteria, and protozoa [ 22 , 23 ]. Where such environments are subjected to intensive anthropogenic human pressures (e.g., wastewater and human sewage disposal and industrial discharges), the dominant cyanobacteria can co-occur with additional biological toxins (e.g., [ 19 ]), chemical pollutants e.g., metals [ 23 ], and with pathogenic microbes [ 24 ]. Examples of the co-occurrence of cyanotoxins, plus other chemical agents and microbial pathogens, and cases of co-exposure are reviewed ( Figure 1 ).…”

Monitoring Lipophilic Toxins in Seawater Using Dispersive Liquid—Liquid Microextraction and Liquid Chromatography with Triple Quadrupole Mass Spectrometry

“…2019/627) [ 11 ] with liquid chromatography and tandem mass spectrometry (LC-MS/MS) for controlling lipophilic toxins. Thus, the literature describes different methodologies for the separation, identification, and quantitation of marine toxins, with LC being the most widely used, especially in combination with a fluorescence detector (FLD) [ 12 , 13 ] and diode array detector (DAD) [ 14 ] for the analysis of shellfish and fish, or a mass spectrometer (MS) [ 2 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ] to check compliance with the maximum permitted levels in shellfish and fish, or sediments [ 2 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , …”

Simultaneous Pre-Concentration and HPLC-MS/MS Quantification of Phycotoxins and Cyanotoxins in Inland and Coastal Waters

“…MCs are hepatic cyanotoxins, produced by prokaryotic and photosynthetic bacteria called cyanobacteria. Although they are widespread mainly in freshwater, they have also recently even been detected in marine ecosystems [13,14]. Their structure consists of a cyclic heptapeptide which contains D-alanine, D-eritro-methyl aspartate, D-glutamate, N-methyldehydro-alanine, a characteristic aromatic amino acid known as Adda, and two variable amino acids (X and Z) in positions 2 and 4 ( Figure 1).…”