Dear Research Gate Users,
I am searching for method of soil sample preparation for Carbohydrates content determination with GC/MS and HPLC.
Would you please help me in this way?
Thank you in advance,
Firouzeh
Dear Bruce,
I want to determine and extract carbohydrates of soil and it has been done by some researchers.
I suppose you can extract the carbohydrates (small chain only like starch and not mucopolysaccharides) with hot water then derivatize the extract with TMS. The silylated carbohydrate is extracted in Hexane, concentrated, and shot into a GC. But I am still dubious!
The extraction of polyaromatic aromatic compounds from the fibrous filter by separating funnel, (15 ml of methanol and dichloromethane mixture and 1: 1). After that, the funnel is placed in a vibrator for 12 hours to ensure that the polyaromatic compounds are dissolved in the solvent mixture.
After extraction, the extract was concentrated by rotary evaporator To less than 1 ml and complete the size to 1 ml
I agree with Bruce. When you extract the carbohydrate from soil, you will need some cleanup to get rid of possible matrices. The final extract should be converted to a TMS derivative with a suitable reagent like BSTFA. The TMS derivatives can be analyzed on GCMS using a suitable capillary column like Rtx-Sil 5 MS.
Can you specify which compound are you specifically talking about? Which particular carbohydrates? Polysacchrides like cellulose ?
Dear Dubey,
Yes. I want to determine cellulose,hemicellulose,glucose and fructose.
glucose is normally in the bound form as a monomeric unit of recalcitrant soil polymers, e.g. lignocellulose. Released by the action of hydrolytic enzymes, glucose is immediately consumed by active microbial cells. The same process (release and consumption) happens with glucose as a part of root exudation. The equilibrium concentration of glucose even in a very fertile soil is less than 1 ug/g, hard to detect.
See attached on silylation reagents;
https://www.sigmaaldrich.com/catalog/search?term=BSTFA&interface=All&N=0&mode=match%20partialmax&lang=en®ion=DK&focus=product
https://www.sigmaaldrich.com/catalog/search?term=BSTFA+TMS&interface=All&N=0+220003052&mode=partialmax&lang=en®ion=DK&focus=site
Also;
https://www.sigmaaldrich.com/catalog/product/aldrich/375934?lang=en®ion=DK&gclid=CjwKCAiA-KzSBRAnEiwAkmQ151WwZVQKjV1v81QbElzkRtaJgXjlOz1R4KOPMV-4nG4M0qi4yzZzmBoCUiMQAvD_BwE
Dear Firouzeh,
TMS means Tri Methyl Sillyl. It is the derivative formed when a compound with a reactive group like -OH or -NH2 is reacted with a sillylating reagent. BSTFA is a sillylating reagent. It stands for N,O-Bis(Trimethyl sillyl) Trifluoroacetamide. It is a very powerful sillylating reagent. There are many others also.... Regards, Girijan Menon
Dear Menon,
Thank you so much for your explanations.
Best regards,
Firouzeh
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