On-line heat-assisted push/pull perfusion hollow fiber liquid–liquid–liquid microextraction for the rapid determination of phthalate esters in river water samples

Abstract

In this study, we evaluated three advanced effects of push/pull perfusion (PPP) and heat on the extraction efficiencies of neutral analytes, following on from previous studies in which we employed on-line sample cleanup and enrichment—combining PPP and ultrasonication with hollow-fiber liquid–liquid–liquid microextraction (HF-LLLME)—for the extraction of acidic phenols from aqueous samples. First, we observed acceptor phase fluid loss or gain occurring in the push-only perfusion-based and pull-only perfusion-based HF-LLLME modes, but not in the PPP mode. Second, we found that heating is a simple technique for improving the extraction kinetics of model neutral compounds (low-molecular-weight phthalates, LPAEs) when using PPP-assisted HF-LLLME. Third, the time required for extraction of these LPAEs through on-line heat-assisted PPP HF-LLLME decreased by as much as 86% relative to that required for conventional off-line HF-LLLME. From an investigation of the factors affecting the heat-assisted PPP HF-LLLME of LPAEs, we established optimal extraction conditions with a sampling time of just 4 min, providing enrichment factors in the range 171–199.