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SINC reacts with amino acids in 0.5 M borate buffer (pH 9.5) within 1 min at room temperature to form
naphthylcarbamoyl derivatives [57] (Figs. 3.5D and 3.13). The rapid reaction and the removal of
excessive reagent by hydrolysis make SINC suitable for automated pre-column derivative formation
[58]. The intense fluorescence allows the determination of subpicomole quantities.

SIPC [59] and AQC [60] also are developed.

(5) Benzofurazans

Halogenobenzofurazan reagents, NBD-Cl [61] and NBD-F [62-64], react with both primary and
secondary amino compounds (Fig. 3.14) at 50-60°C under alkaline conditions (pH 8-9). The reaction
with NBD-F is more than ten times faster than that with NBD-Cl, and is complete within 1 min. As the
hydrolyzed product of the reagents (NBD-OH) also fluoresces intensely, both reagents are used only for
precolumn derivatization. The derivatives of amino acids other than tryptophan can be separated by RP-
HPLC and their detection limits are in the subpicomole range.

DBD-F is developed a a fluorogenic reagent for amines. The sensitivity of the reagent is higher than
that of NBD-F, although the reactivity is less [65].

A noble electrophilic reagent for amines, DBD-COCl, is synthesized [66]. The reagent reacts with
amines (primary and aromatic amines) in benzene solution at room temperature to give

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