“…Except for LC-MS, sialic acids must be derivatized to be photometrically detectable. In addition to thiobarbituric acid, 14,15 a number of reagents including 3,4-diaminotolenene, 32 1,2-diamino-4,5-dimethoxybenzene, 17
O -phenylenediamine, 20 and 1,2-diamino-4,5-methylenedioxybenzene (DMB), 21–29,33,34 have been used for sialic acid derivatization, taking advantage of the special α-keto acid functionality. Among these methods, DMB derivatization for HPLC-fluorescence and LC-MS analyses was the most popular due to the high sensitivity and selectivity of the reaction involved.…”