PBS buffer pH 7.1 - 7.2 (sterile filtered) consists of aqua bidest/pure water, sodium dihydrogen phosphate dihydrate, potassium dihydrogen phosphate and sodium chloride. The solution is sterile filtered through a 0.2 µm micropore filter. This buffer is widely used in medical diagnostics, histology and scientific laboratories, especially for the storage and preparation of biological samples and in cellular applications where the maintenance of physiological pH and ionic strength is essential.

Chemically, the buffer contains sodium dihydrogen phosphate dihydrate (NaH2PO4-2H2O), potassium dihydrogen phosphate (KH2PO4) and sodium chloride (NaCl), the composition of which contributes to a stable pH value. The reaction in the solution aims to create an equilibrium that stabilizes the pH and resists change when acids or bases are added. Applications of the PBS buffer result in improved consistency and reliability in experimental procedures, particularly in cell culture and histological staining. The correct molarities and osmolarities are achieved by precisely calculating the amount of salts, while adjusting the buffer capacity appropriately so as not to interfere with the biological activities of the samples.