Dispersive liquid-liquid aerosol phase extraction for the determination of acetylated bromophenols in urine by gas chromatography - mass spectrometry.

BACKGROUND

Bromophenols are urinary biomarkers of human exposure to brominated flame retardants, but their determination remains challenging because they occur at ultra-trace levels in this complex biological matrix. In this work, dispersive liquid-liquid aerosol phase extraction (DLLAPE) was combined with in-situ aqueous acetylation and gas chromatography-mass spectrometry analysis.

RESULTS

Under optimized conditions, the acetylating reagent (acetic anhydride) and the extracting solvent (heptane) are nebulized directly into the buffered urine sample, generating an interfacial surface area that accelerates mass transfer. The extraction is completed in 80 s and yields a ready-to-inject organic extract through spontaneous phase separation, avoiding the time-consuming centrifugation steps typically required in conventional liquid-liquid extraction. The method demonstrated satisfactory trueness (recoveries of 74-130 %), good overall precision with RSD values generally ≤20 %, and limits of quantification ranging from 70 to 370 pg mL-1 in human urine. Finally, it was successfully applied to urine samples from five healthy adult volunteers with no known exposure to brominated flame retardants, allowing the quantification of several mono-, di-, and tri-bromophenols at sub-ng mL-1 levels.

SIGNIFICANCE: The study represents the first application of DLLAPE to the extraction of organic compounds from aqueous matrices, specifically from urine. It provides a rapid, solvent-minimized, and high-throughput alternative to conventional liquid-liquid extraction for the determination of bromophenols in urine.