Resonance Rayleigh Scattering Spectrometric Determination of Thiamphenicol by Its Reaction with Bromocresol Green

In a Tris-HCl buffer medium of pH 7.56, a definite amount of thiamphenicol was reacted with 1.5 mL of 1.0×10-3mol·L-1 bromocresol green solution in a total volume of 10 mL, to form an ion association complex, of which the intensity of resonance Rayleigh scattering (IRRS) was measured at the RRS peak wavelength of 340 nm. Values of ΔIRRS (difference between values of IRRS of testing solution and blank) was found to keep linear relationship with values of mass concentration of thiamphenicol in the range of 0.02-0.36 mg·L-1, with value of detection limit (3s/k) of 0.065 mg·L-1. The proposed method was applied to the determination of triamphenicol in 2 medicines, and tests for recovery and precision were made by standard addition method using these samples as matrixes. Values of average recovery and RSD＇s (n=6) found were in ranges of 98.9%-102% and 1.4%-1.7% respectively.