Simultaneous determination of thyroxine and triiodothyronine in pharmaceutical formulations using capillary electrophoresis with amperometric detection

摘要

A simple, reliable and repeatable method, based on CE with amperometric detection has been developed for the simultaneous separation and determination of thyroxine (T_4) and 3,3′,5-triiodothyronine (T_3). A carbon disk electrode was used as working electrode in this system and exhibited a good response at 1.05 V (versus Hg/Hg_2Cl_2, 3 mol/L KCl) for two analytes. The CE separations were investigated in detail. At 21 kV of applied voltage, the two compounds were separated within 11 min in 0.05 mol/L Na_2B_4O_7-NaOH buffer (pH 11.3). And the detection limits were as low as 1.0 × 10~(-7) mol/L for T _4 and 8.5 × 10~(-8) mol/L for T_3 (S/N = 3), respectively. The proposed method was applied to analyze T_4 and T_3 in pharmaceutical formulations, and the results were satisfactory.