Effect of Thenardite on the Direct Detection of Aromatic Amino Acids: Implications for the Search for Life in the Solar System

Journal Article · Thu Oct 01 00:00:00 EDT 2009 · International Journal of Astrobiology

DOI:https://doi.org/10.1017/S1473550409990231· OSTI ID:993860

Richardson, C Doc; Hinman, Nancy W; Scott, Jill R

With the discovery of Na-sulfate minerals on Mars and Europa, recent studies using these minerals have focused on their ability to assist in the detection of bio/organic signatures. This study further investigates the ability of thenardite (Na2SO4) to effectively facilitate the ionization and identification of aromatic amino acids (phenylalanine, tyrosine, and tryptophan) using a technique called geomatrix-assisted laser desorption/ionization (GALDI) in conjunction with a Fourier transform mass spectrometry (FTICR-MS). This technique is based on the ability of a mineral host to facilitate the ionization and detection of bio/organic molecules. Spectra obtained from each aromatic amino acid alone and in combination with thenardite show differences in ionization mechanism and fragmentation patterns. These differences are due to chemical and structural differences between the aromatic side chains of their respective amino acid. Tyrosine and tryptophan when combined with thenardite were observed to undergo cation-attachment ([M+Na]+), due to the high alkali affinity of their aromatic side chains. Subsequent cation substitution of the carboxyl group led to formation double cation-attached peaks ([M-H+Na]Na+). In contrast, phenylalanine mixed with thenardite showed no evidence of Na+ interaction. Understanding how codeposition of amino acids with thenardite can affect the observed mass spectra is important for future exploration missions that are likely to use laser desorption mass spectrometry to search for bio/organic compounds in extraterrestrial environments.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC07-05ID14517
• OSTI ID: 993860
• Report Number(s): INL/JOU-09-15584; ISSN 1574-3006; TRN: US201024%%177
• Journal Information: International Journal of Astrobiology, Vol. 8, Issue 4; ISSN 1473-5504
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
58 GEOSCIENCES
AFFINITY
AMINO ACIDS
AROMATICS
CATIONS
CHAINS
DESORPTION
DETECTION
EXPLORATION
FRAGMENTATION
IONIZATION
LASERS
MASS SPECTRA
MASS SPECTROSCOPY
PHENYLALANINE
SOLAR SYSTEM
SPECTRA
TRYPTOPHAN
TYROSINE
Aromatic amino acids
Biosignature
Europa
FTICR-MS
GALDI
Geomatrix
Mars
THenardite