摘要:
A simple and direct method without a derivation step for routine analysis of tobramycin has been developed. This method used reversed-phase ion-pair high performance liquid chromatography (HPLC) with a refractive index (RI) detector and a C18 column which is stable at pH above 1.00. The presence of 4.50 mg·mL trifluoroacetic acid (TFA) in the mobile phase improved the protonation of tobramycin and the formation of ion-pairs, and thus reduced its hydrophility. This unique separation–detection combination showed good linearity with correlation coefficients 0.9996 in the concentration range of 0.25–2.50 mg·mL . The quantitation limit and detection limit were determined to be 0.23 mg·mL and 0.071 mg·mL , respectively. Tobramycin was recovered in 98.00%, 98.84% and 99.64% for tobramycin solutions at concentrations of 2.25 mg·mL , 1.50 mg·mL and 0.75 mg·mL , respectively. The relative standard deviations for six spiked samples ranged from 0.20% to 2.40%, indicating a good reproducibility of this method.