Linked Life Data

11541820

Source:http://linkedlifedata.com/resource/pubmed/id/11541820

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6-7
pubmed:dateCreated
1999-6-27
pubmed:abstractText
On Earth, measurements of the ratios of stable carbon isotopes have provided much information about geological and biological processes. For example, fractionation of carbon occurs in biotic processes and the retention of a distinctive 2-4% contrast in 13C/12C between organic carbon and carbonates in rocks as old as 3.8 billion years constitutes some of the firmest evidence for the antiquity of life on the Earth. We have developed a prototype tunable diode Laser spectrometer which demonstrates the feasibility of making accurate in situ isotopic ratio measurements on Mars. This miniaturized instrument, with an optical path length of 10 cm, should be capable of making accurate 13C/12C and 15N/14N measurements. Gas samples for measurement are to be produced by pyrolysis using soil samples as small as 50 mg. Measurements of 13C/12C, 18O/16O and 15N/14N have been made to a precision of better than 0.1% and various other isotopes are feasible. This laser technique, which relies on the extremely narrow emission linewidth of tunable diode lasers (<0.001 cm(-1)) has favorable features in comparison to mass spectrometry, the standard method of accurate isotopic ratio measurement. The miniature instrument could be ready to deploy on the 2003 or other Mars lander missions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
S
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0032-0633
pubmed:author
pubmed:issnType
Print
pubmed:volume
46
pubmed:owner
NASA
pubmed:authorsComplete
Y
pubmed:pagination
805-12
pubmed:dateRevised
2006-4-17
pubmed:meshHeading
pubmed:articleTitle
Stable isotope laser spectrometer for exploration of Mars.
pubmed:affiliation
SETI Institute, NASA Ames Research Center, Moffett Field, CA 94035-1000, USA.
pubmed:publicationType
Journal Article