“…Although FL detection is another sensitive determination method for HA and the metabolites, the labeling with an FL reagent is essential. The pre-, post-and oncolumn labeling of amino groups at the N α -and/or N τ -position(s) of HA and the metabolites are generally carried out by suitable FL reagents, such as orthophthalaldehyde (OPA)/thiol (Yamatodani et al, 1985;Itoh et al, 1991Itoh et al, , 1992Saito et al, 1992;Skofitsch et al, 1981;Devalia et al, 1985;Kasziba et al, 1988;Siegel et al, 1990a,b;Robert et al, 1983), fluorescamine (van Haaster et al, 1994), 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F; Toyo'oka et al, 2004;Kawanishi et al, 2006Kawanishi et al, , 2007 and 4-bromomethyl-7-methoxycoumarine (4-BrMC; Tsuruta et al, 1987). 4-(N,N-dimethylaminosulfonyl)-7-piperazino-2,1,3-benzoxadiazole (DBD-PZ) is also adaptable for the labeling of the carboxylic acid in MIAA and IAA (Kawanishi et al, 2006).…”