Finding of perchlorates on Mars may provide a

On Aug 12, 11:11 pm, (David Williams) wrote:
- However, having a source of oxygen is one thing. Using it for metabolism i
- another. There must be "food" for the organism to oxidize. What exists in
- Martian soil that an organism could use as food?

- How about hydro-carbons?
- Ken

Have they been detected in Martian soil?

dow


Methane which is a simple organic molecule has been detected in small
amounts from orbit. Methane consisting of carbon and hydrogen is a
hydrocarbon. So organics of some form do exist at the surface of
Mars. This is not proof of life though since methane being a simple
molecule can be produced in purely chemical ways.
Some microbes can survive on methane alone of course. It is also
interesting that some strains of the perchlorate-metabolizers are
autotrophic meaning they do not need to feed on organic compounds.
Some can feed on just CO2 from the atmosphere as their sole carbon
source.
Note though that if the microbes that did not require organic
molecules to feed on were found, autotrophs, then the organic
molecules in their makeup would be returned to the Martian soil when
they died so almost certainly there would exist other microbes that
feed on organics in their metabolism on Mars as well.
Most Mars scientists who have studied the Viking GCMS (gas
chromatography mass spectrometer) now realize that it could have
missed low amounts of organics on Mars. For instance the low numbers
of organics in the driest parts of Antarctica and the Atacama desert
were not detected in experiments using GCMS analog instruments. For
this reason most experts on the issue now say that more sensitive
organic detectors have to be sent to Mars to decide the question.
Here is one article discussing the issue:

The limitations on organic detection in Mars-like soils by thermal
volatilization-gas chromatography-MS and their implications for the
Viking results.
Proceedings of the National Academy of Sciences, October 31, 2006 vol.
103 no. 44 16089-16094
"The failure of Viking Lander thermal volatilization (TV) (without or
with
thermal degradation)-gas chromatography (GC)-MS experiments to detect
organics
suggests chemical rather than biological interpretations for the
reactivity of
the martian soil. Here, we report that TV-GC-MS may be blind to low
levels of
organics on Mars. A comparison between TV-GC-MS and total organics has
been
conducted for a variety of Mars analog soils. In the Antarctic Dry
Valleys and
the Atacama and Libyan Deserts we find 10-90 ìg of refractory or
graphitic carbon per gram of soil, which would have been undetectable
by the
Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto
and
Panoche Valley) and the Mars simulant (palogonite), oxidation of the
organic
material to carbon dioxide (CO2) by iron oxides and/or their salts
drastically
attenuates the detection of organics. The release of 50-700 ppm of CO2
by
TV-GC-MS in the Viking analysis may indicate that an oxidation of
organic
material took place. Therefore, the martian surface could have several
orders
of magnitude more organics than the stated Viking detection limit.
Because of
the simplicity of sample handling, TV-GC-MS is still considered the
standard
method for organic detection on future Mars missions. We suggest that
the
design of future organic instruments for Mars should include other
methods to
be able to detect extinct and/or extant life."
http://www.pnas.org/content/103/44/16089.full

Two things are very notable he first, that iron-containing
minerals of the type expected to be on Mars would have made the GCMS
sensitivity even worse, and second, rather surprisingly, the amounts
of CO2 released on heating in the Viking GCMS might actually have
indicated that organics *were* present.

Bob Clark

Hi Bob, Dave and all.

On Aug 13, 4:49 am, Robert Clark wrote:
On Aug 12, 11:11 pm, (David Williams) wrote:

- However, having a source of oxygen is one thing. Using it for metabolism i
- another. There must be "food" for the organism to oxidize. What exists in
- Martian soil that an organism could use as food?

- How about hydro-carbons?
- Ken

Have they been detected in Martian soil?

dow

Methane which is a simple organic molecule has been detected in small
amounts from orbit. Methane consisting of carbon and hydrogen is a
hydrocarbon. So organics of some form do exist at the surface of
Mars. This is not proof of life though since methane being a simple
molecule can be produced in purely chemical ways.
Some microbes can survive on methane alone of course. It is also
interesting that some strains of the perchlorate-metabolizers are
autotrophic meaning they do not need to feed on organic compounds.
Some can feed on just CO2 from the atmosphere as their sole carbon
source.
Note though that if the microbes that did not require organic
molecules to feed on were found, autotrophs, then the organic
molecules in their makeup would be returned to the Martian soil when
they died so almost certainly there would exist other microbes that
feed on organics in their metabolism on Mars as well.
Most Mars scientists who have studied the Viking GCMS (gas
chromatography mass spectrometer) now realize that it could have
missed low amounts of organics on Mars. For instance the low numbers
of organics in the driest parts of Antarctica and the Atacama desert
were not detected in experiments using GCMS analog instruments. For
this reason most experts on the issue now say that more sensitive
organic detectors have to be sent to Mars to decide the question.
Here is one article discussing the issue:

The limitations on organic detection in Mars-like soils by thermal
volatilization-gas chromatography-MS and their implications for the
Viking results.
Proceedings of the National Academy of Sciences, October 31, 2006 vol.
103 no. 44 16089-16094
"The failure of Viking Lander thermal volatilization (TV) (without or
with
thermal degradation)-gas chromatography (GC)-MS experiments to detect
organics
suggests chemical rather than biological interpretations for the
reactivity of
the martian soil. Here, we report that TV-GC-MS may be blind to low
levels of
organics on Mars. A comparison between TV-GC-MS and total organics has
been
conducted for a variety of Mars analog soils. In the Antarctic Dry
Valleys and
the Atacama and Libyan Deserts we find 10-90 ìg of refractory or
graphitic carbon per gram of soil, which would have been undetectable
by the
Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto
and
Panoche Valley) and the Mars simulant (palogonite), oxidation of the
organic
material to carbon dioxide (CO2) by iron oxides and/or their salts
drastically
attenuates the detection of organics. The release of 50-700 ppm of CO2
by
TV-GC-MS in the Viking analysis may indicate that an oxidation of
organic
material took place. Therefore, the martian surface could have several
orders
of magnitude more organics than the stated Viking detection limit.
Because of
the simplicity of sample handling, TV-GC-MS is still considered the
standard
method for organic detection on future Mars missions. We suggest that
the
design of future organic instruments for Mars should include other
methods to
be able to detect extinct and/or extant life."http://www.pnas.org/content/103/44/16089.full

Two things are very notable he first, that iron-containing
minerals of the type expected to be on Mars would have made the GCMS
sensitivity even worse, and second, rather surprisingly, the amounts
of CO2 released on heating in the Viking GCMS might actually have
indicated that organics *were* present.
Bob Clark

Thanks Bob.
I figure methane and higher HC's are leaking out
of Mars, comparing that to Titan and Earth where
it is very evident.

I figure the 1st plants fed directly from terrestrial
carbon sources that leaked to the surface and
that formed coal as they died off, then later when
that source was used up, photosynthesis evolved,
and plants and trees *learned* how to get C from
CO2 using sunlight which is extremely advanced
technology.

I'm leaning more toward the possibility of life on
Mars.
Regards
Ken

On Aug 13, 4:49 am, Robert Clark wrote:
On Aug 12, 11:11 pm, (David Williams) wrote:

- However, having a source of oxygen is one thing. Using it for metabolism i
- another. There must be "food" for the organism to oxidize. What exists in
- Martian soil that an organism could use as food?

- How about hydro-carbons?
- Ken

Have they been detected in Martian soil?

dow

BTW Dave, People have told us that toronto and
the southern ontario have had record rain on top
of record snow last winter. Do you know why?

Anyway we're glad we're moved out of Muskoka
where record amounts of mosquitoes and black
flies (and the flies from dog ****) are making life
hell cuz of rain.

We read the smog and polluted drinking water
will decrease IQ's even more especially in children
and cause more sexually ambiguous births, that's
babies born without proper sex organs.
Toronto makes Beiging look like a paradise!
Not much you can do about it either, as IQ's fall
corruption increases as emotion replaces reason,
which is rampant in ontario and canada.

We're a bit warm here,
http://www.weatheroffice.gc.ca/forec...l?bc-27&unit=i
but up in the mountains we're usually 10F cooler
than Vernon, otherwise the summer has been perfect.
Regards
Ken

On Aug 13, 7:49 am, Robert Clark wrote:
On Aug 12, 11:11 pm, (David Williams) wrote:

- However, having a source of oxygen is one thing. Using it for metabolism i
- another. There must be "food" for the organism to oxidize. What exists in
- Martian soil that an organism could use as food?

- How about hydro-carbons?
- Ken

Have they been detected in Martian soil?

dow

Methane which is a simple organic molecule has been detected in small
amounts from orbit. Methane consisting of carbon and hydrogen is a
hydrocarbon. So organics of some form do exist at the surface of
Mars. This is not proof of life though since methane being a simple
molecule can be produced in purely chemical ways.
Some microbes can survive on methane alone of course. It is also
interesting that some strains of the perchlorate-metabolizers are
autotrophic meaning they do not need to feed on organic compounds.
Some can feed on just CO2 from the atmosphere as their sole carbon
source.
Note though that if the microbes that did not require organic
molecules to feed on were found, autotrophs, then the organic
molecules in their makeup would be returned to the Martian soil when
they died so almost certainly there would exist other microbes that
feed on organics in their metabolism on Mars as well.
Most Mars scientists who have studied the Viking GCMS (gas
chromatography mass spectrometer) now realize that it could have
missed low amounts of organics on Mars. For instance the low numbers
of organics in the driest parts of Antarctica and the Atacama desert
were not detected in experiments using GCMS analog instruments. For
this reason most experts on the issue now say that more sensitive
organic detectors have to be sent to Mars to decide the question.
Here is one article discussing the issue:

The limitations on organic detection in Mars-like soils by thermal
volatilization-gas chromatography-MS and their implications for the
Viking results.
Proceedings of the National Academy of Sciences, October 31, 2006 vol.
103 no. 44 16089-16094
"The failure of Viking Lander thermal volatilization (TV) (without or
with
thermal degradation)-gas chromatography (GC)-MS experiments to detect
organics
suggests chemical rather than biological interpretations for the
reactivity of
the martian soil. Here, we report that TV-GC-MS may be blind to low
levels of
organics on Mars. A comparison between TV-GC-MS and total organics has
been
conducted for a variety of Mars analog soils. In the Antarctic Dry
Valleys and
the Atacama and Libyan Deserts we find 10-90 ìg of refractory or
graphitic carbon per gram of soil, which would have been undetectable
by the
Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto
and
Panoche Valley) and the Mars simulant (palogonite), oxidation of the
organic
material to carbon dioxide (CO2) by iron oxides and/or their salts
drastically
attenuates the detection of organics. The release of 50-700 ppm of CO2
by
TV-GC-MS in the Viking analysis may indicate that an oxidation of
organic
material took place. Therefore, the martian surface could have several
orders
of magnitude more organics than the stated Viking detection limit.
Because of
the simplicity of sample handling, TV-GC-MS is still considered the
standard
method for organic detection on future Mars missions. We suggest that
the
design of future organic instruments for Mars should include other
methods to
be able to detect extinct and/or extant life."http://www.pnas.org/content/103/44/16089.full

Two things are very notable he first, that iron-containing
minerals of the type expected to be on Mars would have made the GCMS
sensitivity even worse, and second, rather surprisingly, the amounts
of CO2 released on heating in the Viking GCMS might actually have
indicated that organics *were* present.

Bob Clark

Review of the controversy about the sensitivity of Viking GCMS sent
to Mars to detect organic molecules:

Secrets of the martian soil.
Corinna Wu
Nature, 16 Aug 2007, p 742-744 v 448
http://www.mediabistro.com/portfolio...Ee4129Gees.pdf


Bob Clark

On Aug 13, 7:49 am, Robert Clark wrote:
On Aug 12, 11:11 pm, (David Williams) wrote:

- However, having a source of oxygen is one thing. Using it for metabolism i
- another. There must be "food" for the organism to oxidize. What exists in
- Martian soil that an organism could use as food?

- How about hydro-carbons?
- Ken

Have they been detected in Martian soil?

dow

Methane which is a simple organic molecule has been detected in small
amounts from orbit. Methane consisting of carbon and hydrogen is a
hydrocarbon. So organics of some form do exist at the surface of
Mars. This is not proof of life though since methane being a simple
molecule can be produced in purely chemical ways.
Some microbes can survive on methane alone of course. It is also
interesting that some strains of the perchlorate-metabolizers are
autotrophic meaning they do not need to feed on organic compounds.
Some can feed on just CO2 from the atmosphere as their sole carbon
source.
Note though that if the microbes that did not require organic
molecules to feed on were found, autotrophs, then the organic
molecules in their makeup would be returned to the Martian soil when
they died so almost certainly there would exist other microbes that
feed on organics in their metabolism on Mars as well.
Most Mars scientists who have studied the Viking GCMS (gas
chromatography mass spectrometer) now realize that it could have
missed low amounts of organics on Mars. For instance the low numbers
of organics in the driest parts of Antarctica and the Atacama desert
were not detected in experiments using GCMS analog instruments. For
this reason most experts on the issue now say that more sensitive
organic detectors have to be sent to Mars to decide the question.
Here is one article discussing the issue:

The limitations on organic detection in Mars-like soils by thermal
volatilization-gas chromatography-MS and their implications for the
Viking results.
Proceedings of the National Academy of Sciences, October 31, 2006 vol.
103 no. 44 16089-16094
"The failure of Viking Lander thermal volatilization (TV) (without or
with thermal degradation)-gas chromatography (GC)-MS experiments to detec organics suggests chemical rather than biological interpretations for the reactivity of the martian soil. Here, we report that TV-GC-MS may be blind to low levels of organics on Mars. A comparison between TV-GC-MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic Dry Valleys and the Atacama and Libyan Deserts we find 10-90 ìg of refractory or graphitic carbon per gram of soil, which would have been undetectable by the Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO2) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50-700 ppm of CO2 by TV-GC-MS in the Viking analysis may indicate that an oxidation of organic material took place. Therefore, the martian surface could have several orders of magnitude more organics than the stated Viking detection limit. Because of the simplicity of sample handling, TV-GC-MS is still considered the standard method for organic detection on future Mars missions. We suggest that the design of future organic instruments for Mars should include other methods to be able to detect extinct and/or extant life."
http://www.pnas.org/content/103/44/16089.full

Two things are very notable he first, that iron-containing
minerals of the type expected to be on Mars would have made the GCMS
sensitivity even worse, and second, rather surprisingly, the amounts
of CO2 released on heating in the Viking GCMS might actually have
indicated that organics *were* present.


Note then that water vapor and CO2 were evolved at high temperatures
on the first Phoenix TEGA sample, the "dry" one:

NASA Phoenix Media Telecon - June 26.
http://www.nasa.gov/mission_pages/ph...20080626..html

Organic molecules were not specifically detected but again this could
be due to the organics decomposing to CO2.
Because of the known decomposing effects of the Mars iron compounds on
organics, perhaps some ways need to be explored where this effect
could be mitigated in the current TEGA instrument. For instance,
estimated amounts of ice in soil in the north polar region from
orbital observations could be 25% and above. Perhaps if a high ice
containing sample is successfully delivered to TEGA, we could heat the
soil first only to the level that would allow this water to remain
liquid. Then perhaps the iron compounds would become oxidized and this
would reduce the oxidizing effects of the iron compounds on the
organics. This might be helped by free oxygen that was found to be
evolved in one of the TEGA samples. Or perhaps the iron compounds
would dissolve in water after a sufficiently long period of time.
Then after the iron-compounds were oxidized or decomposed, the
temperatures would be raised to the level to volatilize the organics
and detect them then.


Bob Clark

On Aug 21, 8:48 pm, Robert Clark wrote:
...
The limitations on organic detection in Mars-like soils by thermal
volatilization-gas chromatography-MS and their implications for the
Viking results.
Proceedings of the National Academy of Sciences, October 31, 2006 vol.
103 no. 44 16089-16094
"The failure of Viking Lander thermal volatilization (TV) (without or
with thermal degradation)-gas chromatography (GC)-MS experiments to detec organics suggests chemical rather than biological interpretations for the reactivity of the martian soil. Here, we report that TV-GC-MS may be blind to low levels of organics on Mars. A comparison between TV-GC-MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic Dry Valleys and the Atacama and Libyan Deserts we find 10-90 ìg of refractory or graphitic carbon per gram of soil, which would have been undetectable by the Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO2) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50-700 ppm of CO2 by TV-GC-MS in the Viking analysis may indicate that an oxidation of organic material took place. Therefore, the martian surface could have several orders of magnitude more organics than the stated Viking detection limit. Because of the simplicity of sample handling, TV-GC-MS is still considered the standard method for organic detection on future Mars missions. We suggest that the design of future organic instruments for Mars should include other methods to be able to detect extinct and/or extant life."

http://www.pnas.org/content/103/44/16089.full



Two things are very notable he first, that iron-containing
minerals of the type expected to be on Mars would have made the GCMS
sensitivity even worse, and second, rather surprisingly, the amounts
of CO2 released on heating in the Viking GCMS might actually have
indicated that organics *were* present.


It is important to keep in mind that though organics were not
specifically identified with the Phoenix TEGA samples tested so far,
it is possible that organics existed in the samples because of what
*was* evolved: water and CO2. You can gather that from what was said
by TEGA scientist William Boynton in the June 26th news conference:

NASA Phoenix Media Telecon - June 26.
http://www.nasa.gov/mission_pages/ph...20080626..html

Quote:
================================================== =========
What we found first of all, there was no ice in this particular
sample. This is not surprising to us because this was a surface
sample.
And, if you remember, it was actually sitting over the TEGA ovens for
several days while we were working to get it through the screen to get
it into the oven. We also found when we heated the sample that some
small amounts of carbon dioxide were released from the surface of the
grains at relatively low temperatures. Again, this is nothing that's
too unexpected.We know that carbon dioxide is very capable of sticking
onto grain surfaces. So this was what we expected. what we did find
when we heated the sample up to higher temperatures though, is we got
small amounts of carbon dioxide released and also some modest amounts
of water vapor. Again, this is what we were hoping to see expecting
that the samples might have interacted with water and carbon dioxide
in the past.
And indeed, we were successfully able to show that. At this point,
it's rather difficult to quantify exactly how much was given off and
to really do the mineral identifications. That's probably going to
take several more weeks of analysis before we'll be really sure of
what we're seeing.
What we can say now is that this soil clearly has interacted with
water in the past. We don't know whether that interaction occurred in
this particular area in the northern polar regions or whether it might
have happened elsewhere and been blown up to this area as dust. So
that's what I can say about TEGA at this point.
================================================== =========

As we saw it is possible that organics decomposed to only give off
CO2. William Boynton said the possibility of organics being the source
of the CO2 couldn't be ruled out:

Quote:
================================================== =========
Ken [Cramer]: Hi. Thank you. For Bill Boynton, just to follow up on
the TEGA results are you definitely excluding organics? You did not
find any organic material and any carbonates?
Bill Boynton: A-actually at this point, we can't really either include
or exclude organics. We-we-we didn't see any signal that was clearly
organic in nature. But at this particular time, the way we ran the
analysis we weren't using our maximum sensitivity. So at-at this
point, it's -- we-we can't say, yes, we found them. Nor can we say
they are not present. So we-we just haven't seen any conclusive
evidence for them at this time.
But it's-it's really going to take a while before we'll be able to say
anything about the organics. And, as I think you're aware, even if we
do see them, we then have the problem of determining whether they are
terrestrial organics that we brought along with us or whether they're
Martian organics. And, we'll have to analyze our blank sample that we
carried along with us in order to be able to answer that question.
================================================== =========

Also, interesting is that the water evolved was due to bound water in
minerals. This would be most likely due to sulfates, carbonates, or
phyllosilicates(clays):

Quote:
================================================== =========
Emily Lakdawalla: Hi. This is for Bill Boynton. The water vapor that
was given off in your highest temperature run, would that be
consistent with the water coming from bound water in minerals or even
with hydroxyl groups] and phylosilicates or something. Is it part of a
mineral structure? Or would it be actual water inside the soil?
Bill Boynton: No. It's actually, well, that's -- your first suggestion
is almost certainly the case. That associated, bound up in some
minerals. It's not just surface absorbed water or any lightly bound
water. At-at some point, we'll be able to identify or at least narrow
down what types of minerals this might be. But it -- at this point,
all we can say is it's almost certainly some type of chemically bound
water or hydroxyl.
================================================== =========


Bob Clark

On Aug 21, 8:48 pm, Robert Clark wrote:
On Aug 13, 7:49 am, Robert Clark wrote:

On Aug 12, 11:11 pm, (David Williams) wrote:

- However, having a source of oxygen is one thing. Using it for metabolism i
- another. There must be "food" for the organism to oxidize. What exists in
- Martian soil that an organism could use as food?

- How about hydro-carbons?
- Ken

Have they been detected in Martian soil?

dow

Methane which is a simple organic molecule has been detected in small
amounts from orbit. Methane consisting of carbon and hydrogen is a
hydrocarbon. So organics of some form do exist at the surface of
Mars. This is not proof of life though since methane being a simple
molecule can be produced in purely chemical ways.
Some microbes can survive on methane alone of course. It is also
interesting that some strains of the perchlorate-metabolizers are
autotrophic meaning they do not need to feed on organic compounds.
Some can feed on just CO2 from the atmosphere as their sole carbon
source.
Note though that if the microbes that did not require organic
molecules to feed on were found, autotrophs, then the organic
molecules in their makeup would be returned to the Martian soil when
they died so almost certainly there would exist other microbes that
feed on organics in their metabolism on Mars as well.
Most Mars scientists who have studied the Viking GCMS (gas
chromatography mass spectrometer) now realize that it could have
missed low amounts of organics on Mars. For instance the low numbers
of organics in the driest parts of Antarctica and the Atacama desert
were not detected in experiments using GCMS analog instruments. For
this reason most experts on the issue now say that more sensitive
organic detectors have to be sent to Mars to decide the question.
Here is one article discussing the issue:

The limitations on organic detection in Mars-like soils by thermal
volatilization-gas chromatography-MS and their implications for the
Viking results.
Proceedings of the National Academy of Sciences, October 31, 2006 vol.
103 no. 44 16089-16094
"The failure of Viking Lander thermal volatilization (TV) (without or
with thermal degradation)-gas chromatography (GC)-MS experiments to detec organics suggests chemical rather than biological interpretations for the reactivity of the martian soil. Here, we report that TV-GC-MS may be blind to low levels of organics on Mars. A comparison between TV-GC-MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic Dry Valleys and the Atacama and Libyan Deserts we find 10-90 ìg of refractory or graphitic carbon per gram of soil, which would have been undetectable by the Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO2) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50-700 ppm of CO2 by TV-GC-MS in the Viking analysis may indicate that an oxidation of organic material took place. Therefore, the martian surface could have several orders of magnitude more organics than the stated Viking detection limit. Because of the simplicity of sample handling, TV-GC-MS is still considered the standard method for organic detection on future Mars missions. We suggest that the design of future organic instruments for Mars should include other methods to be able to detect extinct and/or extant life."

http://www.pnas.org/content/103/44/16089.full



Two things are very notable he first, that iron-containing
minerals of the type expected to be on Mars would have made the GCMS
sensitivity even worse, and second, rather surprisingly, the amounts
of CO2 released on heating in the Viking GCMS might actually have
indicated that organics *were* present.

Note then that water vapor and CO2 were evolved at high temperatures
on the first Phoenix TEGA sample, the "dry" one:

NASA Phoenix Media Telecon - June 26.http://www.nasa.gov/mission_pages/ph...diobriefing-20...

Organic molecules were not specifically detected but again this could
be due to the organics decomposing to CO2.
Because of the known decomposing effects of the Mars iron compounds on
organics, perhaps some ways need to be explored where this effect
could be mitigated in the current TEGA instrument. For instance,
estimated amounts of ice in soil in the north polar region from
orbital observations could be 25% and above. Perhaps if a high ice
containing sample is successfully delivered to TEGA, we could heat the
soil first only to the level that would allow this water to remain
liquid. Then perhaps the iron compounds would become oxidized and this
would reduce the oxidizing effects of the iron compounds on the
organics. This might be helped by free oxygen that was found to be
evolved in one of the TEGA samples. Or perhaps the iron compounds
would dissolve in water after a sufficiently long period of time.
Then after the iron-compounds were oxidized or decomposed, the
temperatures would be raised to the level to volatilize the organics
and detect them then.

Bob Clark

Question about the "evaporation sequence".

I've been informed that not only do the iron compounds known to exist
on Mars catalyze the breakdown of organics at high temperatures but so
also does perchlorate. This is consistent with what was said about
perchlorate in the Mars Phoenix news conference that it was a weak
oxidant but becomes more active at high temperatures.
Then a breakdown in the TEGA instrument of organics could be coming
from two sources making their detection more difficult. Yet the
detection of evolved CO2 only at high temperatures in TEGA tantalizing
suggests they might be there.
Because of the importance of detecting organics on Mars means should
be investigated for mitigating the decomposing effects of the minerals
in the soil on organics. One possibility would be by dissolving the
iron compounds and perchlorate in liquid water, if a sample could be
delivered to TEGA with a sizable ice content. Jarosite a ferric
sulfate shown to decompose organics was proven by the MER rovers to
exist on Mars and is soluble in water, as is also perchlorate. But
when you heated the sample to detect the organics the water would
evaporate and the iron compounds and perchlorate would precipitate out
again so would presumably still have their oxidizing effect on the
organics.
But what if the iron compounds and perchlorate could be separated from
the organics? MER rover scientists during the discovery by Opportunity
of sedimentary deposits mentioned there appeared to be an "evaporation
sequence" where different minerals precipitated out at different
times. Did this mean they were present in separated layers?
If so, then perhaps by slow heating of the water in the TEGA sample
the iron compounds and the perchlorate could be made to precipitate
out in separate well defined layers that would allow at least some of
the organics not to come in contact with those layers.


Bob Clark

On Aug 28, 12:49 pm, Robert Clark wrote:
On Aug 21, 8:48 pm, Robert Clark wrote:
...
Most Mars scientists who have studied the Viking GCMS (gas
chromatography mass spectrometer) now realize that it could have
missed low amounts of organics on Mars. For instance the low numbers
of organics in the driest parts of Antarctica and the Atacama desert
were not detected in experiments using GCMS analog instruments. For
this reason most experts on the issue now say that more sensitive
organic detectors have to be sent to Mars to decide the question.
Here is one article discussing the issue:

The limitations on organic detection in Mars-like soils by thermal
volatilization-gas chromatography-MS and their implications for the
Viking results.
Proceedings of the National Academy of Sciences, October 31, 2006 vol..
103 no. 44 16089-16094
"The failure of Viking Lander thermal volatilization (TV) (without or
with thermal degradation)-gas chromatography (GC)-MS experiments to detec organics suggests chemical rather than biological interpretations for the reactivity of the martian soil. Here, we report that TV-GC-MS may be blind to low levels of organics on Mars. A comparison between TV-GC-MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic Dry Valleys and the Atacama and Libyan Deserts we find 10-90 ìg of refractory or graphitic carbon per gram of soil, which would have been undetectable by the Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO2) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50-700 ppm of CO2 by TV-GC-MS in the Viking analysis may indicate that an oxidation of organic material took place. Therefore, the martian surface could have several orders of magnitude more organics than the stated Viking detection limit. Because of the simplicity of sample handling, TV-GC-MS is still considered the standard method for organic detection on future Mars missions. We suggest that the design of future organic instruments for Mars should include other methods to be able to detect extinct and/or extant life."

http://www.pnas.org/content/103/44/16089.full

Two things are very notable he first, that iron-containing
minerals of the type expected to be on Mars would have made the GCMS
sensitivity even worse, and second, rather surprisingly, the amounts
of CO2 released on heating in the Viking GCMS might actually have
indicated that organics *were* present.

Note then that water vapor and CO2 were evolved at high temperatures
on the first Phoenix TEGA sample, the "dry" one:

NASA Phoenix Media Telecon - June 26.http://www.nasa.gov/mission_pages/ph...diobriefing-20...

Organic molecules were not specifically detected but again this could
be due to the organics decomposing to CO2.
Because of the known decomposing effects of the Mars iron compounds on
organics, perhaps some ways need to be explored where this effect
could be mitigated in the current TEGA instrument. For instance,
estimated amounts of ice in soil in the north polar region from
orbital observations could be 25% and above. Perhaps if a high ice
containing sample is successfully delivered to TEGA, we could heat the
soil first only to the level that would allow this water to remain
liquid. Then perhaps the iron compounds would become oxidized and this
would reduce the oxidizing effects of the iron compounds on the
organics. This might be helped by free oxygen that was found to be
evolved in one of the TEGA samples. Or perhaps the iron compounds
would dissolve in water after a sufficiently long period of time.
Then after the iron-compounds were oxidized or decomposed, the
temperatures would be raised to the level to volatilize the organics
and detect them then.

Bob Clark

Question about the "evaporation sequence".

I've been informed that not only do the iron compounds known to exist
on Mars catalyze the breakdown of organics at high temperatures but so
also does perchlorate. This is consistent with what was said about
perchlorate in the Mars Phoenix news conference that it was a weak
oxidant but becomes more active at high temperatures.
Then a breakdown in the TEGA instrument of organics could be coming
from two sources making their detection more difficult. Yet the
detection of evolved CO2 only at high temperatures in TEGA tantalizingly
suggests they might be there.
Because of the importance of detecting organics on Mars means should
be investigated for mitigating the decomposing effects of the minerals
in the soil on organics. One possibility would be by dissolving the
iron compounds and perchlorate in liquid water, if a sample could be
delivered to TEGA with a sizable ice content. Jarosite a ferric
sulfate shown to decompose organics was proven by the MER rovers to
exist on Mars and is soluble in water, as is also perchlorate. But
when you heated the sample to detect the organics the water would
evaporate and the iron compounds and perchlorate would precipitate out
again so would presumably still have their oxidizing effect on the
organics.
But what if the iron compounds and perchlorate could be separated from
the organics? MER rover scientists during the discovery by Opportunity
of sedimentary deposits mentioned there appeared to be an "evaporation
sequence" where different minerals precipitated out at different
times. Did this mean they were present in separated layers?
If so, then perhaps by slow heating of the water in the TEGA sample
the iron compounds and the perchlorate could be made to precipitate
out in separate well defined layers that would allow at least some of
the organics not to come in contact with those layers.

Bob Clark

This reference on crystallization separation suggests this method
might work:

===============================================
separation and purification :: Crystallization and precipitation --
Britannica Online Encyclopedia.
Principles of specific methods » Equilibrium separations »
Crystallization and precipitation.
Crystallization is a technique that has long been used in the
purification of substances. Often, when a solid substance (single
compound) is placed in a liquid, it dissolves. Upon adding more of the
solid, a point eventually is reached beyond which no further solid
dissolves, and the solution is said to be saturated with the solid
compound. The concentration of the saturated solution depends on the
temperature, in most cases a higher temperature resulting in a higher
concentration.
These phenomena can be employed as a means of effecting separation and
purification. Thus, if a solution saturated at some temperature is
cooled, the dissolved component begins to separate from the solution
and continues to do so until the solution again becomes saturated at
the lower temperature. Because the solubilities of two solid compounds
in a particular solvent generally differ, it often is possible to find
conditions such that the solution is saturated with only one of the
components of a mixture. When such a solution cools, part of the less
soluble substance crystallizes alone, while the more soluble
components remain dissolved.
Crystallization, the process of solidifying from solution, is highly
complex. Seed particles, or nuclei, form in the solution, and other
molecules then deposit on these solid surfaces. The particles
eventually become large enough to fall to the bottom of the container.
In order to achieve a high purity in the crystallized solid, it is
necessary that this precipitation take place slowly. If solidification
is rapid, impurities can be entrapped in the solid matrix. Entrapment
of foreign material can be minimized if the individual crystals are
kept small. It is sometimes necessary to add a seed crystal to the
solution in order to begin the crystallization process: the seed
crystal provides a solid surface on which further crystallization can
take place.
The term precipitation sometimes is differentiated from
crystallization by restricting it to processes in which an insoluble
compound is formed in the solution by a chemical reaction. It often
happens that several substances are precipitated by a given reaction.
To achieve separation in such cases, it is necessary to control the
concentration of the precipitating agent, so that the solubility of
only one substance is exceeded. Alternatively, a second agent can be
added to the solution to form stable, soluble products with one or
more components in order to suppress their participation in the
precipitation reaction. Such compounds, often used in the separation
of metal ions, are called masking agents.
Precipitation was used for many years as a standard method for
separation and analysis of metals. It has now been replaced, however,
by selective and sensitive instrumental methods that directly analyze
many metals in aqueous solutions.

Principles of specific methods » Equilibrium separations » Zone
melting.
Another separation procedure based on liquid-solid equilibria is zone
melting, which has found its greatest use in the purification of
metals. Purities as high as 99.999 percent often are obtained by
application of this technique. Samples are usually in a state of
moderate purity before zone melting is performed.
The zone-melting process is easy to visualize. Typically, the sample
is made into the form of a thin rod, from 60 centimetres to 3 metres
(2 to 10 feet) or more in length. The rod, confined within a tube, is
suspended either horizontally or vertically, and a narrow ring that
can be heated is positioned around it. The temperature of this ring is
held several degrees above the melting point of the solid, and the
ring is made to travel very slowly (a few centimetres per hour) along
the rod. Thus, in effect, a melted zone travels through the rod:
liquid forms on the front side of this zone, and solid crystallizes on
the rear side. Because the freezing point of a substance is depressed
by the presence of impurities, the last portion of a liquefied sample
to freeze is enriched in the impurities. As the molten zone moves
along, therefore, it becomes more and more concentrated with
impurities. At the end of the operation, the impurities are found
solidified at the end of the rod, and the impure section can be
removed simply by cutting it off. Ultrahigh purities can be achieved
through multistage operation, either by recycling the ring several
times or by using several rings in succession.
....
Principles of specific methods » Particle separations » Particle
electrophoresis and electrostatic precipitation.
As the name implies, particle electrophoresis involves the separation
of charged particles under the influence of an electric field; this
method is used especially for the separation of viruses and bacteria.
Electrostatic precipitation is a method for the precipitation of fogs
(suspensions of particles in the atmosphere or in other gases): a high
voltage is applied across the gas phase to produce electrical charges
on the particles. These charges cause the particles to be attracted to
the oppositely charged walls of the separator, where they give up
their charges and fall into collectors.

===============================================
http://www.britannica.com/EBchecked/...-precipitation

There are several techniques for chemical separation discussed here,
most of which wouldn't be available to TEGA since it wasn't designed
to do these types of separations, such as filtration or osmosis
separation.
However, the method of crystallization separation might work. Here
since different materials when dissolved will recrystallize at
different times as the water is slowly evaporated, the particles that
crystallize first will settle to the bottom in the water first, then
others as they crystallize, thus separating the materials into layers.
An analog of the zone melting technique mentioned, might work when
applied to TEGA. However as described here it appears to require a
method of varying where the heating is applied in the TEGA chamber. I
don't know if TEGA has this capability.
Finally, the method of using electric charges to separate out the
materials might work for TEGA since it uses a mass spectrometer. With
a mass spectrometer you detect different molecules by vaporizing and
ionizing them, and determining how fast the different ions move under
applied electric and magnetic fields.
Here, we would first use the electric and magnetic fields to separate
the ionic species dissolved in the water without raising the sample to
high temperatures for vaporization, then later use the usual mass
spectrometer method to determine which molecules are present. We might
also want to further ionize the dissolved ions in the water to help
out the separation process.

Bob Clark