Buffers and isotonic solutions are two separate concepts in chemistry and biochemistry but can often be discussed together.

A buffer is a solution that helps to maintain a stable pH by resisting changes in the acidity or basicity of the solution. Buffers typically consist of a weak acid and its conjugate base, or a weak base and its conjugate acid. These components can react with added acids or bases to mitigate their effects on the solution’s pH.

An isotonic solution, on the other hand, is a solution that has the same concentration of solutes as another solution, meaning that its osmotic pressure is equal to the solute concentration of the other solution. This can be important for physiological processes, as cells require balanced osmotic pressure to maintain their shape and function.

Buffers can be used to create isotonic solutions by adjusting their pH to match the optimum pH range for the physiological system in question. For example, phosphate-buffered saline (PBS) is a common buffer used to create isotonic solutions for biological processes, as the phosphate buffer system helps to resist changes in pH while the saline (sodium chloride) helps to maintain osmotic pressure.

Overall, buffers and isotonic solutions are important tools in a chemist or biochemist’s toolbox for maintaining stable conditions and ensuring that reactions or processes occur as intended.