Identification of a new diarrhoetic toxin in shellfish using liquid chromatography with fluorimetric and mass spectrometric detection.
A new toxin, dinophysistoxin-2B (DTX-2B) was isolated from Irish mussels using silica chromatography, gel permeation, octadecylsilane solid-phase extraction and repeated preparative high-performance liquid chromatography (HPLC). Dinophysistoxin-2 (DTX-2) was also isolated from shellfish using the same procedures. The separation of these toxins in chromatographic fractions was monitored using fluorimetric HPLC following derivatization with 9-anthrylmethyldiazomethane or 1-bromoacetylpyrene. Flow-injection analysis-mass spectrometry (FIA-MS) with an atmospheric pressure ionization (API) and an ionspray (ISP) interface showed a mass spectrum dominated by the protonated molecule, [M+H]+, at m/z 805 for DTX-2B, thus indicating that this new toxin has the same mol.wt as okadaic acid and DTX-2. The low-energy fragment ion spectrum, as produced in FIA-MS experiments by up-front collision-induced dissociation of the protonated molecule of DTX-2B, showed fragment ions corresponding to successive losses of water molecules from the [M+H]+ ion. This low collision energy fragmentation pattern is typical of marine polyether toxins such as okadaic acid, DTX-2 and DTX-1. These results provide strong evidence that DTX-2B is another okadaic acid isomer.
James
K J
KJ
Chemistry Department, Cork RTC, Republic of Ireland.
Carmody
E P
EP
Gillman
M
M
Kelly
S S
SS
Draisci
R
R
Lucentini
L
L
Giannetti
L
L
D000818:Animals; D049872:Bivalvia / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003967:Diarrhea / Q000139:chemically induced*; D005470:Fluorometry; D008387:Marine Toxins / Q000032:analysis*; D013058:Mass Spectrometry
D008387:Marine Toxins