Resonance Scattering Spectra Study of Interaction of Tobramycinwith Ponceau G Dyes and Its Analytical Application

In weak acid medium,tobramycin（TOB） reacts with ponceau G（PG） to form association particles, which enhance the RS intensity greatly and produce three new resonance scattering（RS）peak at 276 nm, 382 nm and 597 nm. The strongest RS peak is at 597 nm. In this paper, the optimum reaction conditions and the spectrum characteristic of TOB-PG system was investigated. The RS intensity is linear to the concentration of TOB in the range of 0.05~6.88 μg/mL. Its regress equation is △I₅₉₇ nm=1.52c-2.68 with a relative coefficient of 0.998 6 and the detection limit is 22.9 ng/mL. The method was applied to the determination of tobramycin in the tobramycin sulfate injections and eye drops samples, with satisfactory results.