Identification of PAH Isomeric Structure in Cosmic Dust Analogues: the AROMA setup

TL;DR

The paper introduces AROMA, a novel setup combining laser desorption and ion trap mass spectrometry, capable of detecting and characterizing aromatic molecules in complex astrophysical samples with high sensitivity.

Contribution

It presents the development of AROMA, a new analytical platform for detecting and analyzing PAHs in cosmic dust analogues and meteorites, including first identifications of specific PAHs in Murchison meteorite.

Findings

Detection limit of 100 femto-grams for PAHs

Identification of pyrene and methylated derivatives in Murchison meteorite

Successful characterization of aromatic species in complex extraterrestrial samples

Abstract

We developed a new analytical experimental setup called AROMA (Astrochemistry Research of Organics with Molecular Analyzer) that combines laser desorption/ionization techniques with ion trap mass spectrometry. We report here on the ability of the apparatus to detect aromatic species in complex materials of astrophysical interests and characterize their structures. A limit of detection of 100 femto-grams has been achieved using pure polycyclic aromatic hydrocarbon (PAH) samples, which corresponds to 2x10^8 molecules in the case of coronene (C24H12). We detected the PAH distribution in the Murchison meteorite, which is made of a complex mixture of extraterrestrial organic compounds. In addition, collision induced dissociation experiments were performed on selected species detected in Murchison, which led to the first firm identification of pyrene and its methylated derivatives in this sample.