Column switching combined with hydrophilic interaction chromatography-tandem mass spectrometry for the analysis of saxitoxin analogues, and their biosynthetic intermediates in dinoflagellates

Yuko Cho, Shigeki Tsuchiya, Renpei Yoshioka, Takuo Omura, Keiichi Konoki, Yasukatsu Oshima, Mari Yotsu-Yamashita

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

Hydrophilic-interaction chromatography (HILIC) is reportedly useful for the analysis of saxitoxin (STX) analogues, collectively known as paralytic shellfish toxins. Column switching and two-step gradient elution using HILIC combined with mass spectrometry enabled the simultaneous analysis of the 15 primary STX analogues and their biosynthetic intermediates, arginine, Int-A’, and Int-C'2, and the shunt product, Cyclic-C’. Crude extracts of toxin-producing dinoflagellates can be injected without any treatment except filtration. Enrichment of the compounds using this method was highly reproducible with respect to retention times (% RSD was under 1%) and highly sensitive (limits of detection (LODs) were in the range 0.9 (Int-C'2) - 116 (C3) μM) in terms of avoiding matrix effects associated with co-eluting substances. Validation studies demonstrated acceptable performance of this method for specificity, repeatability, linearity and recovery. A comparison of the quantitative results for STX analogues in Alexandrium tamarense using HPLC with post-column fluorescent derivatization and the column-switching HILIC–MS method revealed good agreement. The presence of Int-A’, Int-C'2, and Cyclic-C’ in toxic dinoflagellate species with different toxin profiles was confirmed using this method. Our data support the hypothesis that the early stages of the STX biosynthesis and shunt pathways are the same in dinoflagellates and cyanobacteria.

Original languageEnglish
Pages (from-to)109-120
Number of pages12
JournalJournal of Chromatography A
Volume1474
DOIs
Publication statusPublished - 2016 Nov 25

Keywords

  • Alexandrium catenella
  • Alexandrium tamarense
  • Biosynthetic intermediates
  • Dinoflagellate
  • HILIC–LC–MS
  • Paralytic shellfish toxins

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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