A Coaxially Heated Hollow Fibre Membrane Interface for Real-Time, Ultra-Trace Membrane Introduction Mass Spectrometry of Less Volatile Analyte Molecules

摘要

Membrane introduction mass spectrometry (MIMS) is well suited to the real-time analysis of volatile organic compounds (VOCs). With increasing molecular weight and/or decreasing volatility (e.g. due to polarity effects etc.), the applications of MIMS for semi-volatile organic compounds (SVOCs) become less 'real-time', requiring either thermally assisted trap-and-purge strategies or operation of the membrane at elevated temperatures. For aqueous samples, bubble formation and increased water vapour transport to the mass spectrometer reduces the sensitivity possible for SVOC measurement. We report a hollow fibre MIMS interface that is coaxially heated from the interior. This interface demonstrates superior sensitivity (low pptr) for SVOCs in aqueous samples for both continuous and pulsed heater operation when compared to an isothermal MIMS system.