A kit for preparing labeled glycosylamines comprising a MWCO filtration device, a rapid tagging reagent, a denaturing solution and an enzymatic solution, wherein the denaturing solution denatures glycoproteins in a complex matrix to form a denatured complex matrix mixture, the MWCO filtration device is configured to filter the denatured complex mixture, and the enzymatic solution is mixed and incubated with the denatured complex matrix mixture on the filtration device to yield glycosylamines, the rapid tagging reagent derivatizes the glycosylamines which are detectable in liquid chromatography, capillary electrophoresis or mass spectrometry systems.