When should I use cryofixation and chemical fixation?
Cryofixation usually preserves the organelles inside the cells better, but is more work and usually results in TEM images that are lower contrast. Chemical fixation is easier and gives good contrast, but is more likely to destroy details in delicate samples. Chemical fixation will usually be used unless it is found or expected to not work well for a particular sample. It is possible to mix the methods, for example by including glutaraldehyde in freeze substitution solutions. Here is an article that describes everything you asked about in more detail, if you can access it: A comparison of cryo- versus chemical fixation in the soil green algae Jaagiella