On-line membrane extraction liquid chromatography for monitoring semi-volatile organics in aqueous matrices

Membrane extraction is an attractive alternative to conventional extraction methods, such as liquid-liquid extraction and solid phase extraction, because the analytes can be isolated in a continuous fashion. On-line detection can be carried out using a suitable analytical instrument. The objective of this study is to study the enrichment of semi-volatile organic compounds (SVOCs) from an aqueous matrix by on-line membrane extraction, to be followed by liquid chromatographic (ME-LC) analysis for continuous monitoring. The membrane serves as an interface across which liquid-liquid extraction takes place. The SVOCs transfer from the aqueous phase and are concentrated in an organic extractant. The enriched solvent is intermittently injected into an HPLC for analysis. In this paper, the enrichment into the organic phase under different operating conditions and the performance characteristics of the instrumentation are presented.