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- Posts: 145
- Joined: Sat Sep 25, 2004 3:09 pm
Dear all,
Routinely, I derivatize alcohol by pentafluoroproprionic anhydride with some triethylamine and remove excess reagent by adding water/NH3 and back extracting the derivatized analyte by hexane. I read from quite a few articles that excessive anhydride can also be evaporated under a stream of nitrogen at, say 40-50 deg.C. However, I find it impractical and infeasible as residual liquid is still present after an hour and apparently excess derivatizing reagent cannot be removed by this mean. It is the same as for HFAA. TFAA is a bit better, but still takes quite some time to evaporate. Will that be any trick that I have been missing in order to remove the excess reagent in this way? Thanks.
Hubert
Routinely, I derivatize alcohol by pentafluoroproprionic anhydride with some triethylamine and remove excess reagent by adding water/NH3 and back extracting the derivatized analyte by hexane. I read from quite a few articles that excessive anhydride can also be evaporated under a stream of nitrogen at, say 40-50 deg.C. However, I find it impractical and infeasible as residual liquid is still present after an hour and apparently excess derivatizing reagent cannot be removed by this mean. It is the same as for HFAA. TFAA is a bit better, but still takes quite some time to evaporate. Will that be any trick that I have been missing in order to remove the excess reagent in this way? Thanks.
Hubert
