Hydrophilic interaction liquid chromatography--mass spectrometry for the analysis of paralytic shellfish poisoning (PSP) toxins

Hydrophilic interaction liquid chromatography (HILIC) was examined for the separation of paralytic shellfish poisoning (PSP) toxins using the stationary phase TSK-gel Amide-80. The parameters tested included type of organic modifier and percentage in the mobile phase, buffer concentration, pH, flow rate and column temperature. Using mass spectrometric (MS) detection, the HILIC column allowed the determination of all the major PSP toxins in one 30 min analysis with a high degree of selectivity and sensitivity. The high percentage of organic modifier in the mobile phase and the omission of ion pairing reagents, both favored in HILIC, provided limits of detection (LOD) in the range 50-100 nM in selected ion monitoring (SIM) mode on a single quadrupole LC-MS system. LOD in selected reaction monitoring (SRM) mode on a sensitive triple quadrupole system were as low as 5-30 nM. Excellent linearity of response was observed.