chemrox - 12-11-2012 at 17:01
I want to find a system for processing large numbers of soil samples analyzing for oxalic and possibly other low MW acids. This is going to be a
large, two year project involving soils from many different environments. Since I have no support for it yet and possibly never, I have to do
everything as cheaply as possible. The first issue is extraction; what solvent to use? The second is what detection method? A quantitative or
semi-quantitative one is needed. I have found some colorimetric methods for oxalic but the reagents aren't cheap.
[Edited on 13-11-2012 by chemrox]
bfesser - 12-11-2012 at 20:39
What relevant papers have you dug up from the literature? What is the goal of your analysis?
chemrox - 14-11-2012 at 00:34
Good questions-I have one good research paper and a process from an old set of texts on colorimetric methods by Snell & Snell. I will post the
paper tomorrow when I have my other laptop in front of me. The other part of the study is GIS for the fieldwork and I'm comfortable there.
chemrox - 19-11-2012 at 04:40
Here are some of the ones I found online
Attachment: Reference_11_19_2012_042804.pdf (7kB)
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Attachment: Reference_11_19_2012_043039.pdf (4kB)
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Attachment: Reference_11_19_2012_043207.pdf (5kB)
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Attachment: Desk study on total organic carbon (TOC).pdf (95kB)
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Its part of C sequestration study I'm doing so I;m looking for a way to extract a lot of samples and estimate oxalic content in them. Locations will
be determined to within a meter and loaded into a GIS application made in arcmap or one of those. Keeps me stuck in windoze for the duration on at
least one machine.
[Edited on 19-11-2012 by chemrox]
ssdd - 19-11-2012 at 20:45
Reference
"Procedures for the extraction of LMWOAs
Moist field soil (20.0 g) was added to a 100 ml plastic
centrifuge tube, followed by the addition of 10 ml of 1.0 M KF
with pH 4.0 and shaking for 2 h. Soil suspensions were added
with 30 ml of 0.1 M NaOH, and shaken again in a thermostat
reciprocating shaker at 4 ± 0.5 ̊C. After a given time, the
suspension was centrifuged at 10000 rpm for 30 min. The
obtained supernatant was acidified with 0.1 – 5.0 M HCl to
precipitate humic acids, followed by filtration. The filtrates
were extracted three times for the LMWOAs with 10 ml ethyl
acetate. Then, a solution containing the LMWOAs was
obtained by evaporation of the solvent in a rotary evaporator at
40 ̊C and redissolution of the residue in 1 ml double-distilled
water. All of the samples were analyzed in triplicate, unless
otherwise stated."
I work with OAs from soil fungi, I might be able to check at work for what method we use or get a paper from a non-free journal/db
ssdd