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Razzell Hollis J, Sharma S, Abbey W, Bhartia R, Beegle L, Fries M, Hein JD, Monacelli B, Nordman AD. A Deep Ultraviolet Raman and Fluorescence Spectral Library of 51 Organic Compounds for the SHERLOC Instrument Onboard Mars 2020. Astrobiology 2023; 23:1-23. [PMID: 36367974 PMCID: PMC9810352 DOI: 10.1089/ast.2022.0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 08/01/2022] [Indexed: 06/16/2023]
Abstract
We report deep ultraviolet (DUV) Raman and Fluorescence spectra obtained on a SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) analog instrument for 51 pure organic compounds, including 5 carboxylic acids, 10 polycyclic aromatic hydrocarbons, 24 amino acids, 6 nucleobases, and 6 different grades of macromolecular carbon from humic acid to graphite. Organic mixtures were not investigated. We discuss how the DUV fluorescence and Raman spectra exhibited by different organic compounds allow for detection, classification, and identification of organics by SHERLOC. We find that 1- and 2-ring aromatic compounds produce detectable fluorescence within SHERLOC's spectral range (250-355 nm), but fluorescence spectra are not unique enough to enable easy identification of particular compounds. However, both aromatic and aliphatic compounds can be identified by their Raman spectra, with the number of Raman peaks and their positions being highly specific to chemical structure, within SHERLOC's reported spectral uncertainty of ±5 cm-1. For compounds that are not in the Library, classification is possible by comparing the general number and position of dominant Raman peaks with trends for different kinds of organic compounds.
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Affiliation(s)
- Joseph Razzell Hollis
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- Department of Life Sciences, The Natural History Museum, London, United Kingdom
| | - Sunanda Sharma
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - William Abbey
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | | | - Luther Beegle
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Marc Fries
- NASA Johnson Space Center, Houston, Texas, USA
| | - Jeffrey D. Hein
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Brian Monacelli
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Austin D. Nordman
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
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Uckert K, Bhartia R, Beegle LW, Monacelli B, Asher SA, Burton AS, Bykov SV, Davis K, Fries MD, Jakubek RS, Hollis JR, Roppel RD, Wu YH. Calibration of the SHERLOC Deep Ultraviolet Fluorescence-Raman Spectrometer on the Perseverance Rover. Appl Spectrosc 2021; 75:763-773. [PMID: 33876994 DOI: 10.1177/00037028211013368] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We describe the wavelength calibration of the spectrometer for the scanning of habitable environments with Raman and luminescence for organics and chemicals (SHERLOC) instrument onboard NASA's Perseverance Rover. SHERLOC utilizes deep ultraviolet Raman and fluorescence (DUV R/F) spectroscopy to enable analysis of samples from the Martian surface. SHERLOC employs a 248.6 nm deep ultraviolet laser to generate Raman-scattered photons and native fluorescence emission photons from near-surface material to detect and classify chemical and mineralogical compositions. The collected photons are focused on a charge-coupled device and the data are returned to Earth for analysis. The compact DUV R/F spectrometer has a spectral range from 249.9 nm to 353.6 nm (∼200 cm-1 to 12 000 cm-1) (with a spectral resolution of 0.296 nm (∼40 cm-1)). The compact spectrometer uses a custom design to project a high-resolution Raman spectrum and a low-resolution fluorescence spectrum on a single charge-coupled device. The natural spectral separation enabled by deep ultraviolet excitation enables wavelength separation of the Raman/fluorescence spectra. The SHERLOC spectrometer was designed to optimize the resolution of the Raman spectral region and the wavelength range of the fluorescence region. The resulting illumination on the charge-coupled device is curved, requiring a segmented, nonlinear wavelength calibration in order to understand the mineralogy and chemistry of Martian materials.
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Affiliation(s)
- Kyle Uckert
- Jet Propulsion Laboratory California Institution of Technology, Pasadena, CA, USA
| | | | - Luther W Beegle
- Jet Propulsion Laboratory California Institution of Technology, Pasadena, CA, USA
| | - Brian Monacelli
- Jet Propulsion Laboratory California Institution of Technology, Pasadena, CA, USA
| | - Sanford A Asher
- University of Pittsburgh Chemistry Department, Pittsburgh, PA, USA
| | | | - Sergei V Bykov
- University of Pittsburgh Chemistry Department, Pittsburgh, PA, USA
| | | | - Marc D Fries
- 43834NASA Johnson Space Center, Houston, TX, USA
| | | | | | - Ryan D Roppel
- University of Pittsburgh Chemistry Department, Pittsburgh, PA, USA
| | - Yen-Hung Wu
- Jet Propulsion Laboratory California Institution of Technology, Pasadena, CA, USA
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Sapers HM, Razzell Hollis J, Bhartia R, Beegle LW, Orphan VJ, Amend JP. The Cell and the Sum of Its Parts: Patterns of Complexity in Biosignatures as Revealed by Deep UV Raman Spectroscopy. Front Microbiol 2019; 10:679. [PMID: 31156562 PMCID: PMC6527968 DOI: 10.3389/fmicb.2019.00679] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 03/18/2019] [Indexed: 01/27/2023] Open
Abstract
The next NASA-led Mars mission (Mars 2020) will carry a suite of instrumentation dedicated to investigating Martian history and the in situ detection of potential biosignatures. SHERLOC, a deep UV Raman/Fluorescence spectrometer has the ability to detect and map the distribution of many organic compounds, including the aromatic molecules that are fundamental building blocks of life on Earth, at concentrations down to 1 ppm. The mere presence of organic compounds is not a biosignature: there is widespread distribution of reduced organic molecules in the Solar System. Life utilizes a select few of these molecules creating conspicuous enrichments of specific molecules that deviate from the distribution expected from purely abiotic processes. The detection of far from equilibrium concentrations of a specific subset of organic molecules, such as those uniquely enriched by biological processes, would comprise a universal biosignature independent of specific terrestrial biochemistry. The detectability and suitability of a small subset of organic molecules to adequately describe a living system is explored using the bacterium Escherichia coli as a model organism. The DUV Raman spectra of E. coli cells are dominated by the vibrational modes of the nucleobases adenine, guanine, cytosine, and thymine, and the aromatic amino acids tyrosine, tryptophan, and phenylalanine. We demonstrate that not only does the deep ultraviolet (DUV) Raman spectrum of E. coli reflect a distinct concentration of specific organic molecules, but that a sufficient molecular complexity is required to deconvolute the cellular spectrum. Furthermore, a linear combination of the DUV resonant compounds is insufficient to fully describe the cellular spectrum. The residual in the cellular spectrum indicates that DUV Raman spectroscopy enables differentiating between the presence of biomolecules and the complex uniquely biological organization and arrangements of these molecules in living systems. This study demonstrates the ability of DUV Raman spectroscopy to interrogate a complex biological system represented in a living cell, and differentiate between organic detection and a series of Raman features that derive from the molecular complexity inherent to life constituting a biosignature.
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Affiliation(s)
- Haley M. Sapers
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Joseph Razzell Hollis
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | - Rohit Bhartia
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | - Luther W. Beegle
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | - Victoria J. Orphan
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States
| | - Jan P. Amend
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
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