Phosphate buffered saline (PBS) is a buffer solution used in biological research. It is a water based salt solution containing sodium phosphate, sodium chloride and, in some formulations, it contains potassium chloride and potassium phosphate.

Used for the production of platinum nanoparticles (NP-Pt) hydrocolloids, washing of blood sample and SEM (scanning electron microscope) stubs prior to SEM (scanning electron microscopy), preparing the solution of fluorescent lectin wheat germ agglutinin (WGA), dilution of capture antibody during ELISA (enzyme linked immunosorbent assay), for suspension of cell pellets during centrifugation.

One tablet dissolved in 200 ml of deionised water yields 0,01 M phosphate buffer, 0,0027 M potassium chloride and 0,137 M sodium chloride, pH 7,4, at 25 °C.