Determination of Tetracaine N-Oxide in Urine by Gas Chromatography

Abstract

Gas chromatographic method is devised for the determination of tetracaine N-oxide, a metabolite of tetracaine, in urine. Tetracaine N-oxide is converted to methyl p-(N-methyl-N-butylamino) benzoate by treating with trimethylanilinium hydroxide, and it shows satisfactory sensitivity to flame ionization detector. The calibration curve for quantitation is constructed with caffeine as an internal standard. Tetracaine N-oxide was separated from urine by extraction with chloroform. A known amount of this compound added to urine was recovered at the rate of ca. 69% by the proposed procedure.