A crucial aspect of eukaryotic cells is the spatiotemporal organization of biochemical reactions. One of the strategies cells adopt to regulate biochemical processes is the phase separation of soluble molecules in liquid-like structures. Interactions between intrinsically disordered proteins, such as alpha-synuclein, and RNA molecules are the driving force of the phase separation processes. Changes in the interaction network in alpha-synuclein could promote its transition from a liquid to a solid state, associated with neurotoxicity. Since commonly used methods cannot detect nanoscale liquid or solid-state structures, the early-stage phase transition of alpha-synuclein is still unknown. To overcome these limitations, fluorescence correlation spectroscopy (FCS) techniques are here proposed as a high-throughput tool to investigate the kinetics behind alpha-synuclein phase transitions, focusing mainly on the consequences of the interaction with RNAs.