Photoelectron Circular Dichroism in the Photodetachment of Amino Acid Anions

• Published in: Angewandte Chemie International Edition Vol. 60; no. 33; pp. 17861 - 17865
• Main Authors: Krüger, Peter, Weitzel, Karl‐Michael
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 09-08-2021; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Amino acids; Anions; Chemical compounds; Chirality; Circular dichroism; Communication; Communications; Dichroism; Dihydroxyphenylalanine; Electrospraying; Glutamic acid; Ionization; Ions; mass spectrometry; Photodetachment; Photoelectrons; Vapor phases; Vapor pressure; mass spectrometry; circular dichroism; chirality; amino acids
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202107150

The chirality of chemical compounds is of undisputed importance in science and technology. In particular with respect to pharmacological application most molecules of interest cannot be accessed by the powerful techniques developed in recent years for gas phase analytes. Here, we demonstrate that the combination of electrospray ionization (ESI) with the detection of photoelectron circular dichroism (PECD) provides access to chirality information applicable to molecular materials with negligible vapor pressure, for example, amino acids. To this end, glutamic acid and 3,4‐dihydroxyphenylalanine (DOPA) have been electrosprayed into the source of a chirality spectrometer, where photodetachment is enforced and the PECD is detected. The technique can be expected to be conceptually applicable to all chemical systems with chirality based on molecular properties.
Electrospraying allows bringing “molecular elephants” into the gas phase, as phrased by J. B. Fenn, where subsequent chirality analysis—in the current example via photoelectron circular dichroism resulting from photodetachment from anions—reveals the chirality of enantiomers present.