Development and Validation of a Capillary Electrophoresis Method for the Determination of Denatonium Benzoate in Denaturated Alcohol Formulations

Abstract

Capillary electrophoretic (CE) technique was investigated for the rapid analysis of denatonium benzoate (Bitrex), a quaternary ammonium salt, in several denaturated alcohol formulations. The optimized separations were carried out in 0.025 mol L⁻¹ Tris-phosphate electrolyte (pH 7.0) using direct UV detection at 214 nm. In order to prevent precipitation of hydrophobic matrix components in aqueous electrolyte, an electrokinetic sample introduction mode with internal standard (triethylbenzylammonium chloride) was used. Valid calibration (r²=0.998) was demonstrated in the range 2-50 mg L⁻¹ of Bitrex. The detection limit determined for 10 s electrokinetic (5 kV) injection was 0.45 mg L⁻¹ (three times the baseline noise). The proposed method was applied to the determination of Bitrex in various Lithuanian denaturated alcohol formulations and the results were statistically comparable with those obtained by HPLC technique.