pHbufferiliuoksilla

pHbufferiliuoksilla are solutions that resist changes in pH when small amounts of acid or base are added. They achieve this stability through a buffering system, typically a weak acid and its conjugate base or a weak base and its conjugate acid. The pH of such a solution is governed by the ratio of these two forms, described by the Henderson–Hasselbalch equation: pH = pKa + log([A−]/[HA]). Buffer capacity is greatest when this ratio is near unity and the pH is close to the pKa of the buffering pair.

Common buffering systems include phosphate buffers (for pH near 6–8, using species like dihydrogen phosphate and hydrogen phosphate), acetate buffers (pH roughly 4.5–5.5), citrate buffers, and carbonate/bicarbonate systems. Other buffers, such as Tris-HCl and HEPES, are chosen for specific pH ranges and compatibility with biological or analytical applications. Buffers are typically prepared at moderate ionic strength and adjusted to the desired pH with acid or base, then validated with measurement.

Applications span biochemistry, molecular biology, analytics, and laboratory workflows, where maintaining a stable pH is crucial for enzyme activity, protein stability, nucleic acid handling, chromatography, and electrophoresis. Factors such as temperature, concentration, and ionic strength influence buffer performance; most buffers exhibit pH shifts with temperature and have higher capacity at higher concentrations. Safety and compatibility considerations are important, as some buffers may interfere with assays or cell viability.