Chloroform Removal

1. After 2 days, release the pressure in the vacuum-desiccators. Remove the beaker of chloroform, and store it in the back of the hood to let the remaining chloroform evaporate.

2. Because it is important that all residual chloroform is removed from the soil samples before proceeding with K2SO4 extractions, reap-ply the vacuum to the desiccator. However, do not seal it: simply detach the vacuum hose (while the tap is running) and allow the air to get back in and circulate. Repeat this procedure a few times to clear the chloroform from the flasks. Then place the flasks near the opening of the fume hood, and lower the window to increase the velocity of wind flowing over the flasks (the removal of chloroform will take about an hour).

3. Do the potassium sulfate extractions (see earlier section) for the F flasks.

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