Spectrophotometry of trypan blue determining the content of neomycin

In the condition of PH 2.0-6.0,trypan blue (TB) reacts with neomycin sulfate(NEO) to form blue ion association complexes.The maximum absorption wavelength was 680nm,the maximum fading wavelength was 588nm.The molar absorptivities(e) were respectively 9.15x10 3 and 2.87x10 4 L·mol -1 ·cm -1 .The linear range was between 0-13.0 μg/ml and 0-16.0μg/ml.When the dual-wavelength overlapping absorption spectrometry was used to determine neomycin sulfate,the molar absorptivity(e) was 3.79x10 4L·mol -1 ·cm -1 .The method was satisfactory when it was applied to determine the content of the practical samples.