Potassium chloride is a salt commonly used in the preparation of phosphate buffered saline and for the extraction and solubilization of proteins.It is a good potassium source.Also used in the hypotonic KCl-propidium iodide protocol for univariate analysis of metaphase chromosomes ; dissociation of eukaryotic ribosomes into subunits by high concentrations of potassium (0.3-1.0 M); preparation of mitochondria, provides an ionic osmotic support for those tissues that assume a gelatinous consistency upon homogenization.