Multiple Headspace Extraction-Selected Ion Flow Tube Mass Spectrometry (MHE-SIFT-MS). Part 1: A Protocol for Method Development and Transfer to Routine Analysis
Mark J. Perkins, Vaughan S. Langford
Abstract
The toxicity of many volatile organic compounds (VOCs) means that the safety of polymeric and other materials in contact with, or near, pharmaceutical and food products must be assured through sensitive, quantitative measurement. The multiple headspace extraction (MHE) technique was developed in the 1980s to provide quantitative analysis of VOCs in condensed-phase samples. Selected ion flow tube mass spectrometry (SIFT-MS) is a direct-injection mass spectrometry (DIMS) technique that often significantly reduces the analysis time for routine VOCs in headspace compared to gas chromatography (GC) methods. Using the prototypical polystyrene system, this study represents the first detailed application of MHE to SIFT-MS, describing protocols for method development (including optimization of equilibration temperature and time, plus calibration), data evaluation, and adoption of the technique into routine analysis. MHE-SIFT-MS gives an eight-fold throughput advantage over MHE-GC while being highly repeatable (relative standard deviation, RSD, less than 2%).