Electron Attachment Reaction Ionization of Gas-Phase Methylglyoxal.

Authors :: Lu XW
Ren Y
Liu QY
Zhang T
Jiang LX
Wei GP
He SG
Source :: Analytical chemistry [Anal Chem] 2018 Nov 20; Vol. 90 (22), pp. 13467-13474. Date of Electronic Publication: 2018 Oct 31.
Publication Year :: 2018
Abstract: Methylglyoxal (MGLY) plays a significant role in atmospheric chemistry by serving as a key contributor to the formation of active free radicals, ozone, and secondary organic aerosol. Detection of MGLY by traditional chemical ionization such as proton-transfer reaction has several shortcomings such as parent molecule fragmentation. In this study, an electron attachment reaction (EAR) ionization method has been developed for the effective detection of MGLY. Almost no fragmentation was observed during the EAR. The generation of MGLY <superscript>-</superscript> anion in the EAR was further confirmed by cryogenic photoelectron imaging spectroscopy. The concentration of MGLY can be calibrated by using dibromomethane (CH <subscript>2</subscript> Br <subscript>2</subscript> ) as reference gas. The detection sensitivity of MGLY was estimated to be (100 ± 2) mV/ppbv (parts per billion by volume). The O <subscript>2</subscript> , H <subscript>2</subscript> O, CO <subscript>2</subscript> , and trace gases in ambient air have no obvious effects on the detection of MGLY <superscript>-</superscript> anion by the EAR ionization method.