Short Communication

Confirmed identification of gymnodimine in oysters from the west coast of South Africa by liquid chromatography–tandem mass spectrometry

  • B Krock
  • GC Pitcher
  • J Ntuli
  • AD Cembella

Abstract

Mussels Choromytilus meridionalis and oysters Crassostrea gigas were suspended from a mooring off Lambert’s Bay, South Africa, to study the kinetics of lipophilic phycotoxin accumulation and detoxification. The shellfish were subsequently harvested daily over approximately three weeks and analysed for lipophilic phycotoxins by liquid chromatography coupled with tandem mass spectrometry in the multiple reaction monitoring mode. A mass transition typical for the cyclic imine toxin gymno dimine was detected in low but consistent levels in all oyster samples throughout the sampling period, whereas this peak was detected with lesser intensity in only some mussel samples and was frequently below the limit of quantitation (0.02 µg g–1 fresh weight). Comparison of retention times and collisioninduced mass spectra of a certified standard of gymnodimine and an oyster extract provided unambiguous confirmation of the identity of gymnodimine in the shellfish extracts. The absence of known producers of gymnodimine in the plankton, and the non-detection of gymnodimine in filtered water samples collected during the period of study, lead to the conclusion that the shellfish were contaminated at their site of initial collection in Saldanha Bay prior to  deployment off Lambert’s Bay. This finding is the first confirmed evidence of gymnodimine in the  southern Benguela upwelling system.

Keywords: Benguela Current; Choromytilus meridionalis; Crassostrea gigas; cyclic imine toxins; gymnodimine, LC-MS/MS, oyster; South Africa

African Journal of Marine Science 2009, 31(1): 113–118

Author Biographies

B Krock
Alfred-Wegener Institut für Polar- und Meeresforschung, Am Handelshafen 12, 27570 Bremerhaven, Germany
GC Pitcher
Marine and Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa
J Ntuli
Marine and Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa
AD Cembella
Alfred-Wegener Institut für Polar- und Meeresforschung, Am Handelshafen 12, 27570 Bremerhaven, Germany
Section
Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X