Can you please provide the detailed method for sample preperation of fatty acid by using MSTFA reagent for GC & precautions to be taken?
Please also enlighten the advantages of the same over methyl esters.
By Suds on Tuesday, August 19, 2003 - 07:58 am:
I work for US soap company. When assaying fatty acids, soap pellets, or finished bar soaps, we usually make methyl esters, and use a polar column such as SP-2330. Sometomes we do trimethylsilyl derivatization with BSTFA after dissolving in dimethylformamide and use a nonpolar column. If I was looking at trace amounts, I would use TMS derivatization because the liquid-handling logistics are easier. Make sure to do reagent blank assays first, TMS derivatization can react with left-over soap in inlet or head of column to give real "ghost peaks".
By Anonymous on Wednesday, August 20, 2003 - 05:41 am:
Add 1mL of MSTFA to 10mg of FAs. Dissolve and injectt 1 ÁL into the GC onto a methyl silicone or 5% Phenyl Methyl silicone capillary or packed column.
By Anonymous on Tuesday, August 26, 2003 - 11:05 pm:
Because we are also interested in formic acid, we use HPLC to determine fatty acids. UV @ 230nm. No derivatization is required.
By Anonymous on Saturday, September 20, 2003 - 03:53 am:
adding 1 ml to 10 mg FA and injecting onto DB23 capillary column of J & W gives lots of tailing & the peaks are not sharp. please advise
I would also like to know what is the accuracy of internal standard method
By Anonymous on Monday, September 22, 2003 - 06:40 am:
Are you injecting FAs? or TMS ethers? or are you derivitizing the FAs as Methyl esters?
The internal std method is as accurate as your measurements of weights and the reproducibility of your detector over the range of measurement.
Injecting silylating reagents on a DB23 or any cyanopropyl containing phase is not recommended.
By Anonymous on Friday, January 30, 2004 - 05:28 am:
Please look at:
Automated determination of fatty acid methyl ester and cis/trans methyl ester composition of fats and oils.
Sjaak de Koning, Bram van der Meer, Geert Alkema, Hans-Gerd Janssen, Udo A.Th. Brinkman. Journal of Chromatography A, 922 (2001) 391-397.
By Anonymous on Friday, April 30, 2004 - 12:17 pm:
Can you please provide the detailed method for the analysis of monoglycerides by GC using BSTFA?
By Aktarus on Wednesday, June 16, 2004 - 03:45 am:
For the extraction of fames from human plasma we use CHCl3/MeOH. After protein preciptated in the mix by centrifugation we use ALLTECH Meth-Prep II for methylation and purificattion with hexan/water liquid/liquid separation. The hexan is evaporated in cooled speed-vac and the FAMes are diluted in isooctan before injection on SP-2340 from SUPELCO.