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6
Business Benefits
As summarized above, there are different approaches to the analysis of shellfish toxins in seafood
samples. The traditional mouse bioassay has the clear advantage of providing direct toxicological
response. However, the need for specific strains of laboratory mice to perform the test, the potential
to build a resistance against toxins, and the unavoidable “cruelty” of the method make this
approach the method of the past. Analytical scientists have been searching for alternatives and,
although mass spectrometry based on targeted triple quadrupole MS/MS is a very sensitive and
quantitative technique, it does not deliver the complete answer. The potential risk of missing a
toxin due to a targeted approach creates the need for more comprehensive methods.
From this perspective, there are several benefits of using HRAM technology instead of triple
quadrupole MS/MS. The ability to perform screening, quantitation and confirmation in one run
combined with unequivocal selectivity and required detection limits that can be achieved make
HRAM the key approach for future testing. The inherent possibility to search for a theoretically
unlimited number of compounds makes the method easy to expand and develop. The unique
properties of full scan accurate mass acquisition allow researchers to search for structural ana-
logues of most emerging toxins, their metabolites or adducts, many of which may pose
toxicologically relevant effects.
An interesting approach that challenges the capabilities of the technique has been presented
by Ciminiello
et al
.
11
The group used the LTQ Orbitrap XL MS to identify new types of large
molecular weight toxins belonging to groups produced by
Ostreopsis ovata
. Ovatoxins and
palytoxin are compounds with molecular weights of >2000 Da, which makes them very difficult
to detect by conventional triple quadrupole mass spectrometers, which usually have a mass range
below 2000 Da. Using a linear ion trap combined with an Orbitrap mass analyzer allowed
scientists to detect accurate masses of precursors of toxins as well as to perform structural
elucidation and provide fragmentation pathways with accurate mass information. This approach
allowed them to identify new structural analogues and to quantify those analogues in order to
assess the typical profile of
O. ovata
strain metabolites.
Figure 5. Structure of palytoxin (PLTX) with cleavage and example of mass spectra of palytoxin documenting the high molecular weight
nature of the novel types of compounds. Reprinted with permission from: Ciminiello
et al
; Rapid Commun. Mass Spectrom. 24 (2010)
2735–2744.