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Towards matrix‐free femtosecond‐laser desorption mass spectrometry for in situ space research
Author(s) -
MorenoGarcía Pavel,
Grimaudo Valentine,
Riedo Andreas,
Tulej Marek,
Wurz Peter,
Broekmann Peter
Publication year - 2016
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7533
Subject(s) - chemistry , mass spectrometry , analytical chemistry (journal) , matrix assisted laser desorption electrospray ionization , laser ablation , laser , desorption , fragmentation (computing) , polymer , ion , ionization , thermal ionization mass spectrometry , chromatography , optics , organic chemistry , adsorption , physics , computer science , operating system
Rationale There is an increasing interest in the quest for low molecular weight biomarkers that can be studied on extra‐terrestrial objects by direct laser desorption mass spectrometry (LD‐MS). Although molecular structure investigations have recently been carried out by direct LD‐MS approaches, there is still a lack of suitable instruments for implementation on a spacecraft due to weight, size and power consumption demands. In this contribution we demonstrate the feasibility of LD‐MS structural analysis of molecular species by a miniature laser desorption–ionization mass spectrometer (instrument name LMS) originally designed for in situ elemental and isotope analysis of solids in space research. Methods Direct LD‐MS studies with molecular resolution were carried out by means of a Laser Ablation/Ionization Mass Spectrometry (LIMS) technique. Two polymer samples served as model systems: neutral polyethylene glycol (PEG) and cationic polymerizates of imidazole and epichlorohydrin (IMEP). Optimal conditions for molecular fragmentation could be identified for both polymers by tuning the laser energy and the instrument‐sample distance. Results PEG and IMEP polymers show sufficient stability over a relatively wide laser energy range. Under mild LD conditions only moderate fragmentation of the polymers takes place so that valuable structural characterization based on fragment ions can be achieved. As the applied laser pulse energy rises, the abundance of fragment ions increases, reaches a plateau and subsequently drops down due to more severe fragmentation and atomization of the polymers. At this final stage, usually referred to as laser ablation, only elemental/isotope analysis can be achieved. Conclusions Our investigations demonstrate the versatility of the LMS instrument that can be tuned to favourable laser desorption conditions that successfully meet molecule‐specific requirements and deliver abundant fragment ion signals with detailed structural information. Overall, the results show promise for use in similar studies on planetary surfaces beyond Earth where no or minimal sample preparation is essential. Copyright © 2016 John Wiley & Sons, Ltd.