Patent ID: 8609423

Claim:
A method for protein analysis comprising fluorescently labeling a mixture of proteins, wherein said labeling comprises the steps of: a) forming a first reaction mixture by admixing the mixture of proteins with a composition comprising: i) a first buffer having a pH between pH 8 and pH 10, wherein said first buffer does not include buffer components or additives that have primary or secondary amine moieties; ii) an amine reactive fluorogenic reagent; and iii) acetone cyanohydrin, a nitrile, or an alkali cyanide, b) incubating the first reaction mixture for a first incubation time at a first temperature; c) forming a second reaction mixture by admixing a second buffer with the first reaction mixture, wherein the second buffer has a pH between pH 6 and pH 9; d) incubating for a second incubation time at a second temperature; and e) separating and visualizing the fluorescently labeled proteins.