Is it possible to get small RNAs from total RNA? if I precipitate total RNA with 70% ethanol for example, would the small RNAs be in the flowthrough on a miRNeasy column for example?
yes as said in the previous answer, it is possible this miRNAeasy kit is working very good and also precipitate with 100% if you want to have both small and total RNA together in the same fraction.
Purlink is also working very good http://www.thermofisher.com/order/catalog/product/K157001
just a small addition from my side. If you don't use a column, you might also co-precipitate stuff, that you don't really want. So it's a question of how pure your sample needs to be.
Furthermore, there is a protocol in the Appendix of the miRNeasy Handbook, where the separate isolation of longer and smaller RNA is described.