Phoenix mars mission—The thermal evolved gas analyzer

Hoffman, J. H.; Chaney, Roy C.; Hammack, H.

doi:10.1016/j.jasms.2008.07.015

Cited by 75 publications

(44 citation statements)

References 3 publications

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“…EGA measurements, which were implemented as a part of the Phoenix lander thermal evolved gas analyzer (TEGA) and the MSL SAM instrument packages (Hoffman et al 2008;Mahaffy et al 2012), can distinguish allophane and ferrihydrite from their forms chemisorbed with sulfate because the method directly detects evolved S-bearing species at concentration levels expected in martian soils. Manifestations of chemisorbed sulfate and phosphate anions are also observed in VNIR spectra of allophane and TIR spectra of both allophane and ferrihydrite.…”

Section: Implications For Martian Orbital and In-situ Analysesmentioning

confidence: 99%

Recognizing sulfate and phosphate complexes chemisorbed onto nanophase weathering products on Mars using in-situ and remote observationsk

Rampe

Morris

Archer

et al. 2016

American Mineralogist

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Orbital and in-situ data from the surface of Mars indicate that nanophase weathering products are important constituents of martian rocks and soils. Nanophase minerals have the capacity to chemisorb anions like sulfate and phosphate onto their surfaces, but it is not known whether chemisorption is an important or even detectable process via orbital and in-situ observations. The detection of chemisorbed sulfate and phosphate anions on nanophase minerals would constrain the speciation of these anions and past aqueous environmental conditions. Here, we synthesized two nanophase weathering products that are common in terrestrial volcanic soils and have been identified on the martian surface: allophane and nanophase ferric oxide as represented by ferrihydrite. We specifically adsorbed sulfate and phosphate separately onto the nanophase mineral surfaces (4.5 and 1.6 wt% SO 4 2-, and 6.7 and 8.9 wt% PO 4 3-on allophane and ferrihydrite, respectively) and analyzed the untreated and chemisorbed materials using instruments similar to those on orbital and landed Mars missions (including X-ray diffraction, evolved gas analysis, Mössbauer spectroscopy, and VNIR and thermal-IR spectroscopy). Evolved gas analysis is the optimum method to detect chemisorbed sulfate, with SO 2(g) being released at >900 °C for allophane and 400-800 °C for ferrihydrite. Chemisorbed sulfate and phosphate anions affect the thermal-IR spectra of allophane and ferrihydrite in the S-O and P-O stretching region when present in abundances of only a few weight percent; S-O and P-O stretching bands are apparent as short-wavelength shoulders on Si-O stretching bands. Sulfate and phosphate anions chemisorbed to allophane have small but measurable effects on the position of the OH-H 2 O bands at 1.4 and 1.9 mm in near-IR spectra. Chemisorbed sulfate and phosphate anions did not affect the X-ray diffraction patterns, Mössbauer spectra, and visible/near-IR spectra of ferrihydrite. These data suggest that sulfate chemisorbed onto the surfaces of nanophase minerals can be detected with the Sample Analysis at Mars (SAM) instrument on the Mars science laboratory Curiosity rover, and subtle signatures of chemisorbed sulfate and phosphate may be detectable by IR spectrometers on landed missions. The combined use of SAM, the Chemistry and Mineralogy (CheMin) instrument, and the Alpha Particle X-ray Spectrometer (APXS) on Curiosity allows for the most detailed characterization to date of nanophase minerals in martian rocks and soils and the potential presence of chemisorbed anionic complexes.

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Section: Implications For Martian Orbital and In-situ Analysesmentioning

confidence: 99%

Recognizing sulfate and phosphate complexes chemisorbed onto nanophase weathering products on Mars using in-situ and remote observationsk

Rampe

Morris

Archer

et al. 2016

American Mineralogist

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“…The two Viking landers [ Biemann et al , 1976, 1977] heated the soil to 500°C in an attempt to drive off volatile organic compounds or decomposition products. The Thermal Evolved Gas Analyzer (TEGA) on Phoenix [ Hoffman et al , 2008] performed a similar experiment with additional heating up to 1000°C. However, the Viking landers saw mainly releases of carbon dioxide and water [ Biemann et al , 1976, 1977], and the analysis of TEGA data have, to date, uncovered no conclusive traces of organic molecules [ Ming et al , 2009].…”

Section: Introductionmentioning

confidence: 99%

“…However, the Viking landers saw mainly releases of carbon dioxide and water [ Biemann et al , 1976, 1977], and the analysis of TEGA data have, to date, uncovered no conclusive traces of organic molecules [ Ming et al , 2009]. Since both spacecraft instruments were capable of detecting organic compounds in concentrations as low as a few ppb [ Hoffman et al , 2008; Biemann et al , 1976, 1977], it would be logical to conclude that there are no organic components within Martian regolith.…”

Section: Introductionmentioning

confidence: 99%

UV degradation of accreted organics on Mars: IDP longevity, surface reservoir of organics, and relevance to the detection of methane in the atmosphere

Moores

Schuerger

2012

J. Geophys. Res.

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[1] Reanalysis of the Viking Lander results on Mars has suggested a surface reservoir of organic carbon at the ppm level. The size of this putative reservoir could be explained if the source of carbon on Mars is meteoritic in origin and is destroyed primarily by UV irradiation, yielding methane. By combining a numerical UV model for the surface of Mars with published laboratory measurements of organic UV photolysis, the times required to completely convert the carbon within individual particles to methane may be calculated. For interplanetary dust particles (IDPs) initially containing 10 wt% carbon, lifetimes of organics range from 3.9 years for a 0.2 mm diameter particle at equatorial latitudes to 4900 years for a 200 mm diameter particle at polar latitudes, and implies a median time for IDP organics by UV photolysis of 320 years at equatorial latitudes and 1500 years at polar latitudes. Assuming no redistribution of organics over the surface, the IDP organic reservoir at the surface would range from 1.1 Â 10 À6 kg m À2 at equatorial latitudes to 6.6 Â 10 À6 kg m À2 at polar latitudes. If accreted carbon is evenly mixed with the soil, up to 3.4 ppm of organic carbon at the VL1 landing site can be explained from a meteoritic origin and up to 4.9 ppm at the VL2 landing site. Derived from the IDP organic reservoir, small fluctuations in methane would exist due to variations in UV irradiation with latitude and L S . Production of methane is expected to range up to 0.35 pptv sol À1. Citation: Moores, J. E., and A. C. Schuerger (2012), UV degradation of accreted organics on Mars: IDP longevity, surface reservoir of organics, and relevance to the detection of methane in the atmosphere,

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“…Another fascinating development that took place in parallel was the development of portable or miniaturized mass spectrometers [9 -14]. An entire issue of this journal [JASMS 2008, 19(10)] has been devoted to this topic under the heading "Harsh Environment Mass Spectrometry" [12,13,[15][16][17][18][19][20][21][22]. Although all of the field-portable mass spectrometers available nowadays are less powerful in terms of sensitivity, mass range, and mass resolving power than their laboratory-based counterparts, the vision is clearly to combine suitable atmospheric pressure sources with portable mass spectrometers to run analyses in subway systems, airports, at sports events, in restaurants, supermarkets, wholesale markets, and perhaps in the future even in the average home.…”

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confidence: 99%

What can we learn from ambient ionization techniques?

Chen

Gamez

Zenobi

2009

J. Am. Soc. Mass Spectrom.

228

178

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Ambient mass spectrometry-mass spectrometric analysis with no or minimal effort for sample preparation-has experienced a very rapid development during the last 5 years, with many different methods now available for ionization. Here, we review its range of applications, the hurdles encountered for its quantitative use, and the proposed mechanisms for ion formation. Clearly, more effort needs to be put into investigation of matrix effects, into defining representative sampling of heterogeneous materials, and into understanding and controlling the underlying ionization mechanisms. Finally, we propose a concept to reduce the number of different acronyms describing very similar embodiments of ambient mass spectrometry. (J Am Soc Mass

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Phoenix mars mission—The thermal evolved gas analyzer

Cited by 75 publications

References 3 publications

Recognizing sulfate and phosphate complexes chemisorbed onto nanophase weathering products on Mars using in-situ and remote observationsk

Recognizing sulfate and phosphate complexes chemisorbed onto nanophase weathering products on Mars using in-situ and remote observationsk

UV degradation of accreted organics on Mars: IDP longevity, surface reservoir of organics, and relevance to the detection of methane in the atmosphere

What can we learn from ambient ionization techniques?

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