Spectrophotometric determination of amikacin,kanamycin, neomycin and tobramycin

A spectrophotometric method for determination of neomycin, kanamycin, tobramycin and amikacin is proposed, based on the Rimini test with disodium pentacyanonitrosylferrate(II) for primary and secondary aliphatic amines. The absorbance of the coloured addition product is measured. Beer's law is valid over a wide concentration range. The method is relatively fast and can be used in control of the manufacture of the antibiotics and their purity, instead of the much slower microbiological method. It is also applicable for determination of these antibiotics in formulations.