Given that you are using an azide-oligo and DBCO-NHS ester for your conjugation, here is a recommended protocol to use: 

1. Dissolve your DBCO-NHS ester in DMSO, as concentrated as possible.
2. Add the DMSO solution to the phalloidin amine. For the best conversion, the molar ratio of DBCO/phalloidin must be > 1.5.
3. To the DMSO solution, add saturated NaHCO₃ to adjust the reaction mixture to a pH > 8.5.
4. Stir or vortex the reaction solution for 1-2 hours.
5. Run HPLC or other purification methods to remove any decomposed DBCO
6. The purified phalloidin-DBCO is ready for clicking with your oligo.