Sensitive determination of low molecular mass phenols by liquid chromatography with chemiluminescence detection for the determination of phenol and 4-methylphenol in urine

Abstract

A rapid, reliable method for the routine determination of phenol and 4-methylphenol in urine samples by liquid chromatography with peroxyoxalate chemiluminescence detection was developed. Phenols were first cleaned up by passing the sample through a LiChrolut EN sorbent column and then derivatized straightforwardly with dansyl chloride (15 min at room temperature) thanks to the micellar catalytic effect provided by Triton X-100 micelles. The derivatives were successfully separated in 15 min on a C₁₈ analytical column and determined using an integrated derivatization chemiluminescence detection unit based on the bis(2,4,6-trichlorophenyl) oxalate–hydrogen peroxide system. Linear ranges from 3 to 500 μg L⁻¹, limits of detection at a signal-to-noise ratio of 3 from 0.3 to 0.5 μg L⁻¹ and relative standard deviations from 2.8 to 4.7% were obtained. The proposed method was applied to the assay of different human urine samples (healthy, smoker and petrol station worker volunteers) and free and total phenol and 4-methylphenol were determined. The proposed method surpasses other chromatographic alternatives for the determination of these phenols in terms of limit of detection and sample requirements for the analysis.