On-line phase-transfer catalysed dansylation of phenolic compounds followed by normal-phase liquid chromatography with fluorescence detection

Abstract A study of the on-line phase-transfer catalysed dansylation of phenolic compounds is presented. The extraction—dansylation is performed in the extraction coil of a home-made flow-injection extraction unit. After phase separation, the organic phase is fed to a normal-phase liquid chromatographic system with fluorescence detection. Ethynyloestradiol, oestradiol and paracetamol are used as test compounds. The influence of temperature on the reaction is examined. Calibration graphs showed good linearity ( r > 0.996) and limits of detection are satisfactory (8 × 10 −7 M for ethynyloestradiol, 2 × 10 −6 M for oestradiol and 5 × 10 −7 M for paracetamol). The method is not applicable for the assay of oxychinoiine, phenylephrine and morphine.