Publication Date:
2017-12-19
Description:
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed
for the detection and quantitation of karlotoxins in the selected reaction monitoring (SRM) mode. This
novel method was based upon the analysis of purified karlotoxins (KcTx-1, KmTx-2, 44-oxo-KmTx-2,
KmTx-5), one amphidinol (AM-18), and unpurified extracts of bulk cultures of the marine
dinoflagellate Karlodinium veneficum strain CCMP2936 from Delaware (Eastern USA), which produces
KmTx-1 and KmTx-3. The limit of detection of the SRM method for KmTx-2 was determined as 2.5 ng
on-column. Collision induced dissociation (CID) spectra of all putative karlotoxins were recorded
to present fragmentation patterns of each compound for their unambiguous identification. Bulk
cultures of K. veneficum strain K10 isolated from an embayment of the Ebro Delta, NW Mediterranean,
yielded five previously unreported putative karlotoxins with molecular masses 1280, 1298, 1332,
1356, and 1400 Da, and similar fragments to KmTx-5. Analysis of several isolates of K. veneficum
from the Ebro Delta revealed small-scale diversity in the karlotoxin spectrum in that one isolate
from Fangar Bay produced KmTx-5, whereas the five putative novel karlotoxins were found among
several isolates from nearby, but hydrographically distinct Alfacs Bay. Application of this LC-MS/MS
method represents an incremental advance in the determination of putative karlotoxins, particularly
in the absence of a complete spectrum of purified analytical standards of known specific potency.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
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