Methods and kits to improve the fluorescent signal of DMB-labeled sialic acids

A method of releasing, labeling and, optionally, analyzing, sialic acids present on a glycoconjugate, said method comprising

• (a) contacting a desired volume of said glycoconjugate with a first aqueous solution, comprising glycine adjusted with an acid to a pH of 1.5-3.2,
• (b) incubating said glycoconjugate with said first aqueous solution for a time and at a temperature sufficient to release said sialic acids from said glycoconjugate, thereby releasing said sialic acids from said glyconjugate,
• (c) cooling said released sialic acids in said first aqueous solution to a temperature of 50° C.±10°,
• (d) contacting said released sialic acids with a solution consisting of (i) an effective amount of 1, 2-diamino-4, 5-methylenedioxybenzene (“DMB”), (ii) a second aqueous solution comprising glycine wherein said solution is pH adjusted to a pH of 1.5-3 with an acid, and (iii) an effective amount of one or more reductants, thereby forming a sample/labeling mixture, and
• (e) incubating said sample/labeling mixture for a time and at a temperature sufficient to label said released sialic acids in said mixture,
• thereby labeling said released sialic acids with DMB.