In the absence of a rotary evaporator, how can a solvent be dried from a solution, thereby leaving the solute for further analysis?
Dear Sunday,
When my rotary evaporator does not work I put my solution in Erlenmeyer and dry it with hair dryer (a dryer used to dry hair). It works in an excellent manner.
An alternative method will be drying using a hot plate. However, you should be careful of overheating. Therefore, you heat until getting a minimum volume, then transfer the solution to the hood and with the help of air you can remove the rest of the solvent.
I prefer to use the hair dryer.
Hoping this will be helpful,
Rafik
Dear Sunday
This depends on the volume of sample but a nitrogen blow down on a warming plate or water bath is an alternative. This way you control the temperature i.e. maintain it below 25 degrees or the volatility of the compounds your interested in and the N2 being ideally an ultrapure grade will not introduce contaminants. However on large volumes or solvents that are not very volatile it can be a long and potentially expensive process in terms of N2 use.
G
@Gary codling, thanks sir. I am dealing with 30-40mL sample volume, however N2 is hardly a cheap commodity in this part of the world. i am therefore looking towards inexpensive methodologies.
@Karaman, sir the method you describe brought me to laughter but on second thought it an ingenious one albeit crude which i'd give a try. Am i using the hand held dryer or the stand-alone model? thank you sir
Using a hadheld dryer could contaminate the dried substance, except it is done in a hood. what do you think sir?
Yes. Any evaporation should be done in the hood to avoid any risk causes by inhaling the vapor of the solvents.
Rafik
An alternative to N2 blow down is to use air. By fitting a stopper to your vessel, it need two tubes, one attached to a contolled vacuum source and the second adjustable one allows air to be draw in and inpinge on the solvent surface. Additionally the vessel containg your sample should rest in a waterbath to stop evaporative cooling causing condensation from the air drawn through.
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