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a column-switching system was introduced instead of the clean-up procedure [229], but chromatograms
of samples were interfered with by co-existences. Thus SPE is preferred. The toxicity of ADAM has not
been reported, but it is a potential carcinogen and skin irritant.

Fig. 1.2.17.
LC-FLD chromatogram for MUS-2, a mussel
tissue reference material, after extraction,
derivatization with ADAM, and clean-up by
optimized silica SPE. Isomers of OA are
marked with asterisks. (Reproduced from ref.
227: J. AOAC Int., (1995) 78, P. 568, Fig. 11.).

Other derivative reagents for DSP toxins are BAP [230]. 9-CA [231,232], 2,3-
(anthracenedicarboximido)ethyl trifluoromethanesulfonate (AEOTf) [233]. According to the report
comparing BAP and ADAM, a clear baseline signal was observed when BAP was used, but the
sensitivity was as low as 1/4 that of ADAM [230]. Being stable, 9-CA replaces ADAM, but its
reactability is inferior to ADAM. Reaction with ADAM proceeds at room temperature (or 37 °C), while
the reaction with 9-CA requires 75 °C or 90 °C. A similar derivatization reaction occurs when 9-CA is
used instead of ADAM; 9-CA yields the same fluorescent products (9-anthrylmethyl ester) of OA and
DTX-1 as the ADAM reaction, and the similar clean-up was used. The big advantage of 9-CA is that it
is relatively inexpensive and it is shelf-stable. Even the reagent solutions once prepared are stable for at
least a week if refrigerated.

On the other hand, being developed as a labeling reagent for fatty acid [234], AE-OTf easily reacts with
OA and DTX-1 and the derivatization reaction completes within 10 min at room temperature.
Moreover, the sensitivity of fluorescent derivatives is high (λex298 nm, λem462 nm), the detection
limit for mussel and scallop was 20-30 ng/g [233].

Tetrodotoxin

In some Asian countries, pufferfish is a highly esteemed food. Most incidents of intoxication by

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