by
LALman » Tue Apr 11, 2023 8:02 pm
bunnahabhain wrote:James_Ball wrote:
...
Muffle furnace at 400-450C will also burn off most organic contamination, I use that to clean injection port liners all the time. If worried about active sites you can silanize the glass with some SylonCT.
Based on your experience, is it OK to heat volumetric flasks etc to 500 °C?
Best regards
Jörg
Probably not if you want them to remain volumetrically accurate. I went to work for a lab that had baked their volumetrics that way and many of them had sagged because they far exceeded 500C. Fortunately I was doing metals not organics and had my own volumetric glassware.
From this link...
https://stason.org/TULARC/science-engin ... index.html"16.2 What is the effect of oven drying on volumetric glassware? (Chemistry)
Many older laboratory texts insist that volumetric glassware should not
be oven dried because of the danger of irreversible and unpredictable
volume changes. However most modern laboratory glassware is now made of
Pyrex, and work by D.R.Burfield has demonstrated that low temperature
drying does not significantly affect the calibration of volumetric
glassware [10]. He demonstrated that exposing volumetric flasks and
pipettes to 320C, either continuously or thermally cycled, resulted in no
significant detectable change to the calibration. He concluded that
"oven temperatures in the range of 110-150C should provide efficient drying
of glassware with no risk of discernible volume changes, even after
prolonged use, providing that Pyrex glass is the material of construction". "