Phosphate buffer pH 7.2 is widely used in medical diagnostics, histology and scientific laboratories where stable pH conditions are required. The product consists of deionized water, di-sodium hydrogen phosphate dihydrate, potassium dihydrogen phosphate and sodium benzoate. These chemicals are mixed in fixed proportions to achieve the desired pH value of 7.2. The di-sodium hydrogen phosphate dihydrate (Na2HPO4-2H2O) and potassium dihydrogen phosphate (KH2PO4) act in combination as a buffer system that resists fluctuations in pH by acting as acid and base buffering substances respectively. Sodium benzoate serves as a preservative to increase the biological stability of the solution. The interaction of these components results in chemical reactions that lead to the formation of a buffer system. The reaction of the phosphate-containing compounds releases corresponding amounts of H+ and OH- ions, which are required to stabilize the pH value in the solution. The resulting solution shows a molarity for di-sodium hydrogen phosphate of about 0.0042 mol/L and for potassium dihydrogen phosphate of about 0.0037 mol/L. The osmolarity of this buffer is estimated to be about 16 mOsmol/kg, and the buffering capacity is in a range that is sufficient for most cell biological and biochemical applications. For example, the phosphate buffer makes it possible to maintain a constant pH value during histological staining processes or in cell culture media. Use in stabilization of pH values.