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Urinary organic acid extraction
Posted: Wed Aug 03, 2011 11:21 am
by chandra
Hello,
Few days back i tried a new methodology for extracting urinary organic acids,in that method i have to dry my extract under the nitrogen gas due to our poor resources we don't get the nitrogen cylinder easily.So i want to ask weather it is ok to evaporate the extract in a higher temperature like 80 degree.The organic phase i am using is ethyl acetate.Tell me some other alternative for drying the extract.
Thankyou
Re: Urinary organic acid extraction
Posted: Wed Aug 03, 2011 11:39 am
by Don_Hilton
Heat and air can be bad for organic molecues. Depending on what the organic acid is and what other stuff is present, this may be OK. But the answer is may. As they say: the devil is in the details. And you've not given many details.
Re: Urinary organic acid extraction
Posted: Wed Aug 03, 2011 11:46 am
by chandra
The organic acid i am looking for is methylmalonic acid ,adipic acid,propionic acid and glutaric acid.
Re: Urinary organic acid extraction
Posted: Wed Aug 03, 2011 12:59 pm
by tlahren
My suggestion would be to do a recovery study of these compounds at elevated temperatures. Spike a standard mixture (known amount) into ethyl acetate and see what your % recovery is afterwards. I have seen in the past while running Oil and Grease testing that our surrogate standard (stearic acid) actually had higher recoveries if we increase the evaporation temp of the extract (up to a certain point). The reduction of time in the evaporation setup actually increased recoveries from a hexane extract. But as I said, only to a certain point and only under specific conditions MAY this be possible for SOME of your analytes. You have a very different solvent and different analytes. You would have to do a few studies to find opimal conditions for your evaporation setup.
Re: Urinary organic acid extraction
Posted: Thu Aug 11, 2011 2:25 pm
by mkbjsh
I think it worth while for you investigate and invest in a small nitrogen generator. PEAK scientific manufacture a wide range. This will free you from gas supplier problems and cylinder rental.
Re: Urinary organic acid extraction
Posted: Thu Aug 11, 2011 11:10 pm
by oscarBAL
Hi Chandra; are you using LC for the analysis; it would be good to know how you di the analysis.
How difficult for you it would be to get SPE cartirdges? I think that use Weak Anion Xchange would be the best; you can loand 10 ml of urine for example and then elute them with 1 ml; you would be concentrating 10 times.