Resonance Rayleigh Scattering Spectrometric Determination of Rifampicin ——Based on Its Complex Reaction with Methyl Violet

In a Tris-HCl buffer medium of pH 9.73, an appropriate amount of rifampicin was reacted with 2.5 mL of 1.0×10-3mol·L-1 methyl violet solution, to form a complex and producing resonance Rayleigh Scattering (RRS), the intensity (IRRS) of which was measured at the wavelength of scattering peak (381 nm). Values of ΔIRRS ［IRRS(sample)-IRRS(blank)］ was found to keep lenear relationship with values of mass concentration of rifampicin in the range within 0.823 mg·L-1, with limit of detection (3s/k) of 0.003 9 mg·L-1. The proposed method was applied to the determination of rifampicin in its drug samples, giving results checked quite well with the results found by the method of pharmacopeia. Values of recovery and RSD′s (n=6) found were in the ranges of 99.0%-102% and 0.8%-1.1% respectively.