Rapid analysis of paralytic shellfish toxins and tetrodotoxins by liquid chromatography-tandem mass spectrometry using a porous graphitic carbon column

Although paralytic shellfish toxins (PSTs) have traditionally been analyzed by liquid chromatography with either pre- or post-column derivatization, and these methods have been validated successfully through inter-laboratory studies, mass spectrometry methods have also been described in literature for use in monitoring programs. However, methods using liquid chromatography coupled with mass spectrometry (LC-MS) need to be improved in terms of sensitivity, analyte recovery and retention time stability because of undesirable matrix effects. Furthermore, tetrodotoxin (TTX) has been found in northern European bivalves, so it is important to analyze TTX compounds alongside PSTs because characteristics of their toxicity are similar. This paper describes, for the first time, a chemical method that allows determination of PSTs, both hydrophilic and hydrophobic, alongside TTX and its analogue 4,9-anhydro tetrodotoxin (4,9-anhTTX) with LC-MS/MS using a Hypercarb® column. The method was validated for 13 hydrophilic PSTs and TTXs and was able to discriminate six hydrophobic PSTs in 20 min. The method was developed for four shellfish matrices: mussel (Mytillus galloprovincialis), clam (Ruditapes decussatus), scallop (Pecten maximus) and oyster (Ostrae edulis). Clean-up procedure used in this work allowed us to obtain good results for validation parameters for both PSTs and TTXs. No standards were available so strains of Gymnodinium catenatum (G. catenatum) were used instead.