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Hi,

I derivatization with cholesterol, solvent and reagent BSTFA, but my peaks are strange, and there are peaks in the void. Do you have an idea of ​​where the problem is and a solution please?

Thanks,
Unwigle

Hello,

If you have run a reaction blank which would contain everything except the cholesterol material and still do not see anything at those retention times, then those peaks would not be attributed to impurities within the solvents or BSTFA reagent. Upon derivatization, the reaction bi-products would elute early within the runtime, most-likely before 10 minutes, since they are small in nature.
Minnie

If you do see peaks in the blank that elute at those times then the purity of the pyridine solvent or of the BSTFA reagent is questionable. Alternative derivatization reagents would be TMSI for a silylation product or TFAA and HFBI for acylation products, where a CF3 addition is formed. The reaction process would be run the same way, with substitution of one of the different reagents. I would prefer acylation over silylation since the product material would possibly be more-volatile and would have a fluorine marker, suitable for MS detection.

Mickey

Thank you Mickey&Minnie !