Sensitive determination of ethacrynic acid in urine samples by reversed-phase liquid chromatography with ultraviolet detection using solid-phase extraction techniques for sample clean-up

Abstract

A rapid method is described for the identification and determination of ethacrynic acid in human urine samples by liquid chromatography with UV detection, the retention time of the analyte being 4.9 min. The samples were previously conditioned using C 18 solid-phase extraction columns and chromatographed on an HP-LiChrospher RP C 18 column (5 μm; 125 mm × 4 mm i.d.) with gradient elution with acetonitrile-acetate buffer (pH 4). The detector was set at 275 nm and furosemide was used as an internal standard. The procedure was applied to the determination of ethacrynic acid at concentrations of 0.01-10 μg ml -1 and the limit of detection was 6 ng ml -1.