Hello Carmen Ortueta Eizmendi

Yes, you can.

Add your SYBR Green master mix and primers to the wells of your RT-qPCR plate. Securely seal the plate with an optical adhesive cover to prevent evaporation and wrap the plate in aluminum foil or store it in a dark place to protect the SYBR Green from light degradation. You may store the plate at 4°C overnight. But just before starting the RT-qPCR run the next day, briefly centrifuge the plate to collect the contents at the bottom of the wells.

Best,