Direct On-Line Measurement of PAHs in Complex Aqueous Samples: Condensed Phase Membrane Introduction Mass Spectrometry - Direct Electron Ionization (CP-MIMS-DEI)

摘要

Polycyclic aromatic hydrocarbons (PAHs) are an important class of environmental contaminants, commonly measured by techniques such as GCMS. They are well suited to electron ionization, but suffer poor sensitivity and impractically long response times with on-line polydimethylsiloxane (PDMS) membrane based MIMS methods using gaseous acceptor phases for membrane-mass spectrometer coupling because of their low volatility. Various heating and/or trap-and-release strategies can help, but increase the duty cycle, reducing the potential for real-time MIMS measurements of PAHs. Condensed phase MIMS (CP-MIMS) uses a liquid acceptor phase for analyte transfer, eliminating the volatility limitation. The logical coupling of CP-MIMS with direct liquid electron ionization (DEI) is presented and characterized for direct, on-line aqueous PAH measurements at low ppb levels in complex samples.