Chromatography Forum

I hope my question is not outside the scope of this forum. I am trying to run a protocol for compositional analysis of lignocellulosic samples (wood) (it is the NREL or ASMT protocol for structural carbohydrates analysis in wood). It involves a two stage hydrolysis of the biomass with concentrated and dilute sulfuric acid, and analysis of the sugars produced by the hydrolysis of cellulose and hemicellulose, on a Pb sugar column. My HPLC seems to be working fine, as I get good results when measuring samples from pretreatment and enzymatic hydrolysis experiments of the wood samples. However my results for the compositional analysis of the solid samples lack both accuracy and reproducibility for the same biomass type. Values measured are always lower than expected which might mean that there is loss of sugars somewhere, or perhaps an incomplete hydrolysis.
Should anyone have any experience with this type of analysis I would appreciate your comments.

So far I remember there were same publications done by the German Helmholtz Zentrum München – Deutsches Forschungszentrum für Gesundheit und Umwelt (HMGU oder HZM), the former GSF-National Research Center for Environment and Health, Institute of Development Genetics, Neuherberg, Germany, several years ago. They used for a similar application a 7,5x60 SEC column based on silica. But usually cellulose can be separated by SEC based on high crosslinked Polymetacrylate. Dr. Bimal Chatterjee was the chemist involved in these research works. He is now retired, but maybe you can find some publications from him. Please google for Bimal Chatterjee GSF or contact my former colleague Christine Wilde at Metrohm GmbH Germany, c.wilde@metrohm.de. I think Christine can give you more information about that application. Good luck.

I hope my question is not outside the scope of this forum. I am trying to run a protocol for compositional analysis of lignocellulosic samples (wood) (it is the NREL or ASMT protocol for structural carbohydrates analysis in wood). It involves a two stage hydrolysis of the biomass with concentrated and dilute sulfuric acid, and analysis of the sugars produced by the hydrolysis of cellulose and hemicellulose, on a Pb sugar column. My HPLC seems to be working fine, as I get good results when measuring samples from pretreatment and enzymatic hydrolysis experiments of the wood samples. However my results for the compositional analysis of the solid samples lack both accuracy and reproducibility for the same biomass type. Values measured are always lower than expected which might mean that there is loss of sugars somewhere, or perhaps an incomplete hydrolysis.
Should anyone have any experience with this type of analysis I would appreciate your comments.

Several things - make sure you use 72% sulfuric and not diluting 98% down to 72% - makes it easier. After hydrolysis - use barium carbonate to neutralize and remove the sulfuric acid as you will form lead sulfate in the column.

You have to make sure your dry mass analysis is done properly.

david.slomczynski@phycal.com

Contact me and I can help you with this.

Dave

ASTM has standard materials you shoul actually us