ULMER buffer pH 7.2 consists of aqua bidest / ultrapure water, potassium dihydrogen phosphate and a sodium hydroxide solution with a concentration of approx. 40 % NaOH. The buffer is primarily used in medical diagnostics, histology and scientific laboratories, where it supports pH stability in various biochemical and histological processes. The pH value of 7.2 is ideal for most biological reactions in cells and tissues. Chemically, potassium dihydrogen phosphate (KH2PO4) consists of the elements potassium (K), phosphorus (P) and oxygen (O), while sodium hydroxide is mainly composed of sodium (Na) and oxygen (O). Together, these components act as a buffer by acting on the concentration of hydrogen ions in solutions, which helps to keep the pH stable. This stabilization is critical for many biological processes and maintaining the structural integrity of tissue samples during processing and staining. The reaction of potassium dihydrogen phosphate and the sodium hydroxide solution in ultrapure water results in the formation of a buffered system that effectively resists fluctuations in pH. The resulting solution shows a constant buffering capacity and ensures the necessary environment for precise scientific experiments and diagnostic tests. Based on the given components, the solution shows an appropriate molarity and osmolarity that provide specific buffering properties for laboratory applications. These enable accurate results in the examinations and experiments performed. pH buffering in histology.