HPLC-HRMS Quantification of the Ichthyotoxin Karmitoxin from Karlodinium armiger

Aaron John Christian Andersen, Lívia Soman De Medeiros, Sofie Bjørnholt Binzer, Silas Anselm Rasmussen, Per Juel Hansen, Kristian Fog Nielsen, Kevin Jørgensen, Thomas Ostenfeld Larsen

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Abstract

Being able to quantify ichthyotoxic metabolites from microalgae allows for the determination of ecologically-relevant concentrations that can be simulated in laboratory experiments, as well as to investigate bioaccumulation and degradation. Here, the ichthyotoxin karmitoxin, produced by Karlodinium armiger, was quantified in laboratory-grown cultures using high-performance liquid chromatography (HPLC) coupled to electrospray ionisation high-resolution time-of-flight mass spectrometry (HRMS). Prior to the quantification of karmitoxin, a standard of karmitoxin was purified from K. armiger cultures (80 L). The standard was quantified by fluorescent derivatisation using Waters AccQ-Fluor reagent and derivatised fumonisin B₁ and fumonisin B₂ as standards, as each contain a primary amine. Various sample preparation methods for whole culture samples were assessed, including six different solid phase extraction substrates. During analysis of culture samples, MS source conditions were monitored with chloramphenicol and valinomycin as external standards over prolonged injection sequences (>12 h) and karmitoxin concentrations were determined using the response factor of a closely eluting iturin A2 internal standard. Using this method the limit of quantification was 0.11 μg·mL-1, and the limit of detection was found to be 0.03 μg·mL-1. Matrix effects were determined with the use of K. armiger cultures grown with 13C-labelled bicarbonate as the primary carbon source.
Original languageEnglish
Article number278
JournalMarine Drugs
Volume15
Issue number9
Number of pages13
ISSN1660-3397
DOIs
Publication statusPublished - 2017

Keywords

  • Harmful algal bloom
  • Ichthyotoxic
  • Karlotoxin
  • Polyether
  • Polyketide
  • Quantify
  • Quantitation
  • Amphidinol

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