An improved borate method for the quantitative distinction of glucosamine (GlcN) and galactosamine (GalN) in a mixture is presented which is based on the Elson-Morgan method with addition of sodium borate to differentiate colour formation by the two hexosamines. The r(2) value and maximum deviation of the method based on calculations derived in this study were 0.9979 and 5.1%, respectively. Using this method, the GlcN/GalN ratio in an exopolysaccharide (EPS) produced by Citrobacter sp. was found to change with time during the production process, with a maximum value at 9.8:1.