A coarse protocol idea would be to run your extracts on a gel or size exclusion columns, while making sure you work in RNase free conditions, reverse transcribe the result, ligate adaptors in 3’ and 5’ - or first ligate and then RT which is a bit more tricky - and amplify the product for subsequent analysis. Alternatively, you could look into RACE (rapid amplification of cDNA ends), some protocols are specifically adapted for sRNA detection, eg. 5’tagRACE.

Thanks Kyle Skalenko and Aymeric Fouquier d'Hérouël for your contributions. Appreciated.