Membrane extraction-preconcentration cell coupled on-line to flow-injection and liquid chromatographic systems. Determination of triazines in oils

This study was initiated to investigate the potential of on-line liquid-liquid extraction with membrane barriers coupled to liquid Chromatographic systems for the fully automated purification and enrichment of complex samples containing very low analyte concentrations. As an illustration, a routine method was developed for the detection of residues of triazine herbicides in oils using a hydrophobic porous membrane. The proposed extraction-preconcentration method with spectrophotometric detection permits the determination of total triazines in samples of corn and sunflower oils. Furthermore, the results obtained on performing the coupling to a liquid Chromatographic system show that the procedure permits the automatic extraction, isolation and determination of individual triazines in complex matrices such as corn, sunflower and olive oils.