This formulation of HEPES buffer at 0.5 M is carefully titrated to pH 7.4 using potassium hydroxide, ensuring close alignment with physiological conditions. HEPES, a zwitterionic Good’s buffer, provides strong pH stability within 6.8–8.2 and resists changes due to CO₂ or temperature fluctuations. This makes it excellent for mammalian cell culture, fluorescence microscopy, and bioprocess monitoring that require both precision and consistency.