10X PBS, pH 7.4, is supplied by HiMedia. It is available in the form of a colourless solution with a pH in the range of 7.3 to 7.5. This is a water-based salt solution containing Sodium chloride, Sodium phosphate and Potassium phosphate. This solution is extensively used for dilution and washing during various biological applications as it maintains the physiological pH and osmolarity. The phosphate groups of this buffer help to maintain a constant pH. The 10X buffer should be diluted to 1X (using nuclease free sterile water) prior to use. Composition of 10X PBS buffer is as follows:

137 mM Sodium chloride

10 mM Disodium hydrogen phosphate

2 mM Potassium dihydrogen phosphate

Phosphate Buffered Saline (PBS) is a common buffer extensively used in molecular biology and biochemistry as it can maintain pH and osmolarity. 10X PBS, pH 7.4 is a concentrated form and has to be diluted to 1X concentration before usage. This buffer is widely used in molecular biology and tissue culture as dilution and wash buffer as it is isotonic and non-toxic to living cells. It is also used as a wash solution and for diluting antibodies during western blotting and immunohistochemical staining. Occasionally while preparing wash solutions, Tween20 is also added.