Analysis and assay of glycated haemoglobins by capillary electrophoresis, buffer compositions and kits for capillary electrophoresis

A method for analysis by capillary electrophoresis of glycated hemoglobin A1c comprising at least one beta globin chain and a glucose residue bound to the amino acid in the N-terminal position of the beta globin chain, contained in a biological sample, said method comprising the following steps:

• a. introducing a buffer composition and biological sample into an electrophoresis capillary, said buffer composition comprising at least one compound which specifically complexes the glucose residue(s) bound to an amino acid in the N-terminal position in hemoglobin A1c of the biological sample, and provides said glycated hemoglobin A1c with several negative electric charges at an alkaline pH, and wherein said compound which specifically complexes the glucose residue(s) of hemoglobin A1c of the biological sample and provides negative charges at an alkaline pH comprises two or more than two functional groups, at least one of said functional group(s) specifically complexing one or several glucose residue(s), thereby providing one negative electric charge per complexed glucose residue, the other, one of the others or all of the other functional group(s), which do not complex said glucose residue(s), providing each of said glucose residue with one or several additional negative electric charge(s) at an alkaline pH and;
• b. performing capillary electrophoresis on the buffered biological sample for separating the constituents of said biological sample, thereby producing an electrophoretic profile comprising a series of fractions, wherein the glycated hemoglobin A1c fraction is separated from other hemogloblins including hemoglobin A1a and hemoglobin A1b found in the biological sample, and;
• c. performing a step for detection of hemoglobin A1c present in the biological sample.