A potential method for comparing instrumental analysis of volatile organic compounds using standards calibrated for the gas phase

In this paper we report a method for the comparative analysis of volatile organic compounds (VOCs) at physiologically representative concentrations by different analytical methods Standard aqueous solutions of acetone, ethanol, methanol, 1-propanol, 2-propanol and acetaldehyde were prepared by adding a specific mass of compound to a known volume of water, calculated using published Henry’s law constants for individual compounds. Headspace concentrations are thus known from established partitioning from dilute aqueous phase in accordance with Henry’s law. Selected Ion Flow Tube Mass Spectrometry (SIFT-MS), Proton Transfer Reaction Mass Spectrometry (PTR-MS), and Gas Chromatography–Mass Spectrometry (GC–MS) coupled to thermal desorption have been used to study and evaluate the performance of the instruments in the analysis of these VOCs. These analytical techniques have been widely used in the identification and quantification of trace concentrations of VOCs in biological samples. Quantitative determination of VOC concentration was achieved and the performance of the instruments compared with one another. Calibration curves are given within the range 101–103 ppbv.