A compact tandem two-step laser time-of-flight mass spectrometer for in situ analysis of non-volatile organics on planetary surfaces

Abstract

Two-step laser desorption mass spectrometry is a well suited technique to the analysis of high priority classes of organics, such as polycyclic aromatic hydrocarbons, present in complex samples. The use of decoupled desorption and ionization laser pulses allows for sensitive and selective detection of structurally intact organic species. We have recently demonstrated the implementation of this advancement in laser mass spectrometry in a compact, flight-compatible instrument that could feasibly be the centerpiece of an analytical science payload as part of a future spaceflight mission to a small body or icy moon.

Miniature and Fieldable Mass Spectrometers: Recent Advances

“…Nonetheless, TOFs have become particularly appealing in space-based instruments, where elemental analysis typically is carried out with laser ablation ionization. 86,89,95,96 …”

“…Miniature mass spectrometers, mostly laser ablation time-of-flight configurations, have been developed in the hopes of being used in future missions. Proven applications of these instruments are isotopic and elemental composition measurements of rocks ,,− and meteorites as well as determination of aromatic organics, amino acids, and nucleotides. , Other technologies developed for space exploration include an electrodynamic ion funnel for use with a laser ablation ion source, an air quality monitor (i.e., GC/MS) combined with an electrothermal vaporization sample introduction system for monitoring both air and water quality on the International Space Station, and CAMAM, an instrument that couples laser ablation time-of-flight to a microscope-camera system for morphological analysis of solids …”

“…Nonetheless, TOFs have become particularly appealing in space-based instruments, where elemental analysis typically is carried out with laser ablation ionization. 86,89,95,96 Quadrupole mass filters are another beam-type analyzer found in small mass spectrometers. 97,98 The origin of this analyzer, which is composed of two sets of parallel rods with hyperbolic cross sections arranged in a square, is found in a 1953 patent filed by Wolfgang Paul.…”

“…This method uses Felgett’s advantage to increase signal-to-noise without sacrificing resolution . Miniature time-of-flight (TOF) instruments have also been developed, − and TOFs have the advantage of simple electronics and high mass range, especially compared to traps and quadrupoles, but like sectors the resolution/size relationship is not favorable to miniaturization. Nonetheless, TOFs have become particularly appealing in space-based instruments, where elemental analysis typically is carried out with laser ablation ionization. ,,, …”