Atmospheric Pressure Chemical Ionisation study of selected Volatile Organic Compounds (VOCs) by Ion Mobility Spectrometry coupled with orthogonal acceleration Time Of Flight Mass Spectrometry

Abstract

In this work, we present an Atmospheric Pressure Chemical Ionisation (APCI) study of several organic solvents relevant to Thin Layer Chromatography (TLC) (methanol, ethanol, propan-2-ol, acetone, ethyl acetate, diethylamine). The solvents were investigated using an Ion Mobility Spectrometry (IMS) combined with orthogonal acceleration Time Of Flight Mass Spectrometry (IMS-oaTOF MS). The solvents were iononised by Reactant Ions (RI – H+.(H2O)3,4 m/z 55 and 73). The ions were analysed using IMS and IMS-oaTOF technique was used to assign the ion mobility peaks to ions according to their m/z. IMS spectra of methanol, ethanol, propan-2-ol and diethylamine exhibited only one peak (reduced ion mobilities of 2.19, 2.07, 1.98, 2.06 cm2s−1V−1 respectively) whereas acetone and ethyl acetate were characterised by two peaks (2.15, 1.85 and 1.94, 1.53 cm2s−1V−1 respectively). The IMS-oaTOF spectrometry assigned IMS peaks of VOCs to M⋅H+(H2O)n. n = 0,1,2 or M2⋅H+ ions, where M represents the solvent molecule.