In this study, the spectra obtained by the different mass analyzers successively contributed to the elucidation of the fragmentation pathways of PTX2 and OA. In general, to elucidate fragmentation pathways a combination of fragmentation data observed by e.g. an IT-MS and high resolution data obtained by, e.g. QToF-MS, is needed.
All mass analyzers had good linearity and repeatability for PTX2 and OA. The LOD for PTX2 on all mass analyzers was sufficiently low to use them for routine analysis. On the QToF-MS the LOD for OA was too high to use it for routine analysis, but on the other mass analyzers the LOD was good. The most sensitive mass analyzer is the TQ-MS. This mass analyzer is most frequently used for routine quantitative analysis of shellfish samples. For example, OA on TQ-MS system is ten-fold more sensitive than the 9-anthryldiazomethane (ADAM) fluorescence method. On the TQ-MS the LOD for OA was around 3 µg/kg, while for ADAM derivatisation an LOD of 30 µg/kg was reported [21]. The application of LC-MS/MS for lipophilic shellfish toxin analysis is reliable and sensitive enough to be a good candidate to replace the controversial mouse assays which are still prescribed in European legislation.
ACKNOWLEDGEMENTS
This research was undertaken with the financial support of the European Commission, within the 6th Framework project „BIOTOX: Development of cost- effective tools for risk management and traceability systems for marine biotoxins in seafood‟ Contract no: 514074 (www.biotox.org).
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