Quantitation of tetrodotoxin by UPLC-HILIC-MS/MS and HRMS in shellfish and other marine specimens

The presence of tetrodotoxin (TTX) in bivalve shellfish has been reported by several groups, which has prompted a review of its prevalence in shellfish. TTX is most commonly known for its historical human intoxications... [ view full abstract ]

The presence of tetrodotoxin (TTX) in bivalve shellfish has been reported by several groups, which has prompted a review of its prevalence in shellfish. TTX is most commonly known for its historical human intoxications surrounding consumption of tetraodontiformes (e.g. puffer fish) and became an issue in New Zealand when TTX-containing grey side-gilled sea slugs (Pleurobranchaea maculata) washed onto Auckland beaches in 2009 resulting in dog fatalities. TTX has since been reported in a clam species (Paphies australis) found in New Zealand using methodology that monitored either the intact toxin or a C9 reaction product formed when treated with strong base. 

Recently in New Zealand we have implemented a UPLC-MS/MS method for routine monitoring of paralytic shellfish toxins (PST) in commercial and non-commercial shellfish samples. This methodology is also able to be used for simultaneous quantitation of intact TTX, in addition to the routine PST analysis. Some technical challenges have been observed with matrix co-extractives at times causing suppression. The key analogues responsible for matrix suppression have been characterised, and quality control procedures implemented to mitigate this issue. Additionally, we have used MS/HRMS fragmentation to characterise the naturally occurring TTX analogues present in New Zealand marine organisms, and developed a modified acquisition method for targeted UPLC-MS/MS analysis of 18 TTX analogues.