Date of Award


Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy



First Advisor

Dr. Kevin J. James


A highly specific and sensitive LC-MS/MS analytical method was developed and validated using gradient reversed phase liquid chromatography-tandem mass spectrometry (LC- MS/MS), interfaced using turbo-assisted electrospray ionisation (ESI) in negative mode for the analysis of DSP (okadaic acid (OA), dinophysistoxins (DTXs) and pectenotoxins (PTXs)) toxins in a variety of samples. There were no matrix effects present, proved by the good reproducibility achieved and the linearity of the calibration curves (r" > 0.999) in spiked mussel samples and standards. A DSP toxin profile study was conducted with bulk phytoplankton and mussels samples from the west coast of Ireland. All the samples were analysed by LC-MS/MS and in ail the samples, DTX2 was the predominant toxin followed by OA and in minor proportion the PTXs toxins.

Due to the lack of standards available an isolation procedure was developed to isolate DSP toxins from wild phytoplankton using different chromatographic techniques. LC-MS/MS was used as a detection method to determinate components of the chromatographic fractions. Individual fractions of pure compounds were obtained and a hybrid quadrupole time- of flight mass spectrometry was used to determine toxin purity and provide fragmentation data with high mass accuracy.

A number of phytoplankton samples from different locations were analysed for the determination of different PTX toxins and new components belonging to that group were found. Studies involving different mass spectrometers were performed to determine the structures of these new congeners of PTXs.

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