Thermogravimetric analysis (TGA) is a tool used to analyze a sample by measuring mass loss as a function of temperature. A sample of ~2 mg is placed into a platinum crucible (shown in this video). It is subjected to a heating rate of between 5 and 20 °C/min and heated from 20 to 1000 °C. The mass of the sample is measured each second and as the temperature rises it is accurately measured by a thermocouple just below the crucible. Mass loss could be due to evaporation or decomposition, but not combustion as the sample is kept under nitrogen during the heating.
The same sample of flax run four times in one day on the same instrument from 30-700 °C at 10 °C/min
The result is a repeatable pattern of mass loss at each temperature which can tell a lot about each sample. Note here that the furnace was switched from nitrogen to air at 700 C in order to combust away any remaining sample to clean the crucible. Bumps in the curve are due to somebody allowing the lab door to slam shut. Tip: Don't place Vanadium samples in the TGA as this will bond to the platinum and ruin the crucible.
25 g of crude compound mixture has been dry loaded onto 60 g of silica by stirring in DCM. The DCM was carefully removed and the dried silica/compound was evenly spread on top of clean silica. In this video three 100 mL portions of 70% hexanes : 30% EtOAc are poured with the silica under vacuum. Read more in my blog post here.
Video of bulb to bulb distillation using a kugelrohr (17 sec)
If video is slow to load, click below to download in high resolution. File size: 17 MB (MP4 format).