Platinum-coated polystyrene Janus particles are widely studied for their active motion, yet significant variability in reported velocities remains unexplained. This variability arises from the system's sensitivity to experimental methodologies. In this study, we systematically examine key factors influencing particle behavior, including particle preparation, surface cleaning, fluid cell assembly, wait times, fitting parameters, and data reporting. We find that pre-activating particles in peroxide before measurements increases velocities, while variations in surface cleaning protocols and wettability significantly impact results. Additionally, adding peroxide after introducing particles into the fluid cell leads to poor mixing and higher variability. The time elapsed after fluid cell assembly also affects velocities—particles may initially move faster due to transient surface changes or slower if not properly activated. Equilibration time is crucial, as insufficient wait time prevents stabilization, while excessive wait time can introduce bubbles, leading to convective flows. Proper fluid cell assembly is essential to minimize evaporation and convection artifacts. Furthermore, we discuss the impact of fitting parameters on result interpretation and explore statistical tools for distinguishing velocity distributions. Our findings not only clarify sources of variability in the literature but also establish a standardized methodological framework for future studies of active Janus particles.
