The ionization of analytes from a sample surface under ambient conditions for direct mass spectrometric analysis remains challenging work, as a sufficient amount of energy is required to overcome the attraction between their counterparts and the sample surface. Herein, a new ionization technique, namely atmospheric pressure megavolt electrostatic field ionization desorption (APME-FID), is introduced for direct mass spectrometric analyses under ambient conditions. This technology involves the electrostatic charging of an individual, up to megavolt potential using a Van de Graaff generator, without inducing electrical shock to the living individual. Compounds of interest can be ionized and desorbed from the surface of a sample, and detected by a hybrid quadrupole-time-of-flight (Q-TOF) tandem mass spectrometer. Our results show that this technique is applicable to the analysis of a variety of daily samples in their original states. Samples detected include explosives deposited on skin/gloves (e.g., 2,4-dinitrotoluene and 2,4,6-trinitrophenol), flammable solvent on cloth and tissue paper (e.g., toluene), and illicit drugs deposited on bare hands (e.g., cocaine). Moreover, this in-house developed technique can also be used to detect the chemical/biochemical profile of human breath. Volatile substances in human breath, such as diethyl butanedioate and menthol-related compounds, were successfully detected after the volunteers consumed red wine and mint-flavored chewing gum. In conclusion, the feasibiity of APME-FID for the analysis of analytes deposited on large living organisms (e.g., a human body) as well as small objects (clothes and gloves) with minimal sample preparation is presented. This simple, non-invasive and non-destructive technique may significantly widen the application areas of MS technology for field testing in security screening, forensic analysis, metabolic profiling, and other daily sample analysis.

Direct sample analysis by atmospheric pressure megavolt electrostatic field ionization desorption mass spectrometry

248th National Meeting (2014)

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