QUANTITATIVE TLC HPTLC DETERMINATION OF NEOMYCIN-A, NEOMYCIN-B, AND NEOMYCIN-C .1. CHROMATOGRAPHIC-SEPARATION AND POSTCHROMATOGRAPHIC DERIVATIZATION

The quantitative determination of the aminoglycoside antibiotics neomy cin B and C and neamine (neomycin A) by TLC has been investigated. Opt imum separation was achieved within the very short separation time of ca 35 min by ascending one-dimensional development on silica gel 60 F2 54 HPTLC or TLC plates at 50-degrees-C; methanol - 25 % ammonia soluti on - acetone - chloroform (35 + 20 + 20 + 5, v/v) was used as mobile p hase. Postchromatographic derivatization was performed with fluorescam ine and the fluorescence was stabilized, and the fluorescence intensit y increased by a factor of five, by dipping the developed chromatogram in a solution of dichloromethane - triethanolamine - light liquid par affin (8 + 1 + 1, v/v). It was then possible to detect neomycin B and C and neamine simultaneously. The method is so sensitive that it is po ssible to determine the individual neomycin components quantitatively at the very low concentrations at which they are found in neomycin raw materials.