title: Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging-ion mass spectrometry.
abstract: Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron-ion coincidence imaging spectrometer. As proof of concept, vapours containing ∼1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2-4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument.
authors.affiliation: LaserLaB Amsterdam and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands.
authors.forename: Mohammad M Rafiee
authors.initials: MM
authors.lastname: Fanood
authors.affiliation: LaserLaB Amsterdam and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands.
authors.forename: N Bhargava
authors.initials: NB
authors.lastname: Ram
authors.affiliation: LaserLaB Amsterdam and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands.
authors.forename: C Stefan
authors.initials: CS
authors.lastname: Lehmann
authors.affiliation: School of Chemistry, University Park, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: Ivan
authors.initials: I
authors.lastname: Powis
authors.affiliation: LaserLaB Amsterdam and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands.
authors.forename: Maurice H M
authors.initials: MH
authors.lastname: Janssen