MEMS-based force-detected nuclear magnetic resonance spectrometer for in situ planetary exploration

Abstract

Nuclear magnetic resonance (NMR) is the most widely used spectroscopic technique for characterization of molecular structures and reactions. N M R is especially powerful in detecting the presence of water and distinguishing between arbitrary physisorbed and chemisorbed states. This ability is particularly important in the search for extra-terrestrial life on planets such as Mars, where there are strong indications that liquid water exists or has existed previously. Conventional NMR technology based on magnetic induction is unsuitable for remote applications because these instruments are heavy and require excessive power. We recently demonstrated a new N M R technology based on magnetic force detection that is suitable for NMR analysis in remote environments and on small samples [2,3]. This paper details our efforts toward realizing this technology on small scales using a MEMS (micro electro mechanical systems) approach. Applications of this new MEMS-based NMR method to planetary exploration are discussed.

Effect of Hydrogen Bond Formation on the NMR Properties of Glycine–HCN Complexes

“…Because traditional NMR spectrometers are big instruments, lightweight miniature NMR spectrometers have already been developed to search for mineral and organic molecules in extra-terrestrial surface and environment. 73 We report here the results of chemical shielding parameters calculated by DFT method with extended basis sets for the isolated molecules of glycine and HCN. The chemical shifts for all the constituent atoms of the glycine−HCN dimers and trimers are also reported.…”

“…Because HCN is found to take part in the formation of aminoacetonitrile (H 2 NCH 2 CN), a known precursor of glycine, it might be interesting to investigate the hydrogen-bonded glycine–HCN clusters in the gas phase. NMR is an important experimental technique for high-resolution detection of biomolecules in an extraterrestrial environment. − Astrobiological application of NMR is of particular interest to NASA, especially for in situ planetary exploration. Because traditional NMR spectrometers are big instruments, lightweight miniature NMR spectrometers have already been developed to search for mineral and organic molecules in extra-terrestrial surface and environment …”

Electrochemically Fabricated Microelectromechanical Systems/Nanoelectromechanical Systems (MEMS/NEMS)

“…A significant strength of the FDNMR technique over the conventional technique is that it is capable of high-resolution, multi-nuclear analysis [123]. It has been shown previously [122] that the force detection technique is uniquely suited for MEMS sizes and has superior sensitivity over the conventional, inductive detection technique for sample sizes in the range of 10-100 microns. Thus, the MEMS FDNMR spectrometer is the only choice for in-line detection of aqueous samples, as well as dissolved organic samples, in a miniaturized, multi-instrument suite type application.…”

“…13.17). The FDNMR spectrometer is constructed using MEMS fabrication techniques [122]. The detector magnet is mounted on a microfabricated Si beam making up a mechanical resonator.…”

Aerogel keystones: Extraction of complete hypervelocity impact events from aerogel collectors

“…Further advances are anticipated in the next few years. For example, George et al have pointed out that MEMS Force-Detected Nuclear Magnetic Resonance (MEMS FD-NMR) could enable NMR analysis on micron-scale particles [12] because of the very weak scaling of its single-shot signal-to-noise ratio (SSSNR) with sample size m (SSSNR ∼ m sample preparation for analysis in advanced laboratory instruments, remain primitive. In this paper, we focus on the steps between in situ particle identification and analysis -the extraction of impact residues and preparation of extracted samples for analysis.…”