Analysis of aqueous environments by laser desorption/ionization time-of-flight mass spectrometry

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) has been developed and used to characterize different groups of hydrous minerals. We have advanced the technique by including reversed polarity, precision ion gating, and a curved field reflectron mass analyzer. Reversed polarity provides capabilities in achieving complementary compositional information of the materials, and ion gating enhances the selectivity and sensitivity in specific mass ranges. Representative reference minerals including sulfates, clays, serpentine, and naturally collected complex samples have been analyzed by LD-TOF-MS as well as infrared (IR) spectroscopy, to provide supporting information. We demonstrate that mass spectrometry can identify water in mineral species, and reveal the presence of aqueous environments. Miniaturized LD-TOF-MS is a valuable instrument technique for the in situ characterization and analysis of samples as part of future landed planetary missions and astrobiology explorations.