I am using a rotary evaporator to separate DCM (dichloromethane) from some nasty tars. Before the evaporation is completed, I stop the process and collect the remaining slurry. The slurry is then positioned in a constant temperature oven, for a secondary evaporation. After cooling in a desiccator, the tar is measured.
The problem is that some of the tars remain deposited on the flask's wall. I can easily remove them with a soft brush, however this is a problem for 2 reasons:
- Some of the tar is lost, retained on the brush itself ( I require a very high precision since I work with samples of 100 or so mg)
- The amount of DCM for secondary evaporation is increased (I am trying to reduce that amount as much as possible)
Is there a round bottomed flask that has a TEFLON like coating on the inside, that can prevent the tar deposition on the walls?
There seem to be a lot of products that are referred as " Flask with Plastic Safety Coating". On which side is the coating applied (I assume is the outside)