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John Jaksich
2008-Dec-19, 04:39 AM
In a recent post I mistakenly stated that the Viking landers did not have a chromatography experiments---after reading partway through Carl Sagan's The Varieties of Scientific Experience. He states that there was a gas chromatography experiment; and, my information from the book by McLafferty/ Turicek included traces of Mass Spectra from the Martian atmosphere that indicated that Methane was present at that time.

I am to infer that the gas chromatography experiments were not sensitive to detect the presence of methane...even though the Mass Spectrum indicates it is there?:think:

Jeff Root
2008-Dec-19, 05:06 AM
You are aware, aren't you, that the gas chromatograph mass spectrometer
(GCMS) was a single instrument, not two separate instruments?

-- Jeff, in Minneapolis

John Jaksich
2008-Dec-19, 07:31 AM
Hello Jeff,

I had read that there was a GC/MS experiment ( just recently ), but Dr. McLafferty makes the case very strongly from the Viking data that he'd obtained ( and explicitly-- methane was on the surface of Mars ----I presume it might be in hindsight ). I'd used gc instruments w/o the separate ms unit attached in experiments designed to quantitatively analyze the amounts of organic molecules in a mixture of organics.

Point being...the obvious budgetary constraints of the time; as well as, the lack of knowledge of Mars may have prevented a thorough examination of some of the variables that could have been taken into account w/r to Martian atmosphere and geology.

So--if we were to re-examine the Martian milieu in the future, certain "echo-check" experiments should be in place so as to act as preventative false-positive/negative results.

Unfortunately, I don't have the copyrighted permissions to post Dr. McLafferty's and Dr. Turicek's analyses. But, as in previous post: I will give the ISBN 0935702253 and the exact page of NASA trace from his 1993 text: page 5.


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QC454.M3
M39
1993

matthewota
2008-Dec-19, 07:51 PM
I kept all of my Viking Program news releases from the early 1970s. There was a gas chromatogaph mass spectrometer on both landers.

John Jaksich
2008-Dec-19, 10:59 PM
I have performed many gc/ms analyses in industrial work---but I guess that based on the sensitivity of the Viking experimental packages the gc/ms work may have been flawed.

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post script

If you are able to browse the McLafferty's book ---at a library---he does a very-well thought-out analysis of the Viking traces of the atmosphere.