Phosphate buffer
Phosphate Buffer Solution: Phosphate buffer, also commonly known as PBS, is a saline solution used in organic chemistry, natural science and biochemical processes. Since phosphate buffer solution is not poisonous for living organisms, it is used as a cleaning solution and a diluting agent for the cells in the human body. Buffer solutions do not react with acids or alkalis upon dilution. Thus, making them suitable and useful for a variety of industrial and biochemical applications like chemical manufacturing, photography, as antacids in medicines, food additives and agricultural purposes. Buffering agents can either be weak acids or alkalis, used to maintain the acidity or alkalinity of a solution, and resist changes in the pH of the solution. Buffering agents vary in their properties, depending on their nature. While some are acidic, others are basic. A buffer solution usually comprises of a buffering agent diluted with water. Liquids can be classified as acidic or basic, depending on the level of pH they have. The pH is the concentration of hydrogen in a liquid. A low pH indicates an acidic nature while a high pH means that the liquid is basic. A pH of 7 means that the solution or substance is neither acidic nor basic, but neutral.
Potassium In Phosphate Buffer: Phosphate buffer is a saline solution containing sodium chloride, potassium phosphate and sodium phosphate. Phosphate buffer is helpful in managing and maintaining the pH of a solution or the concentration of hydrogen ions in it. Although carbonate buffers also serve the same purpose, phosphate buffered salines are more effective. In order to increase its applications, other chemical compounds like EDTA (ethylenediaminetetraacetic acid) can also be added. Buffer solutions are essential for maintaining the correct pH of enzymes in living organisms. If the right level of pH is not sustained, the enzymes may slow down their activity or stop functioning altogether. Besides biochemistry, buffer solutions are also used industrially like in fermentation, chemical analysis and for dyeing fabrics. The addition of potassium in saline solution helps to stabilize the phosphate buffer. Potassium in phosphate buffer helps to resist the changes in pH, thereby serving the purpose of a buffering agent.
Sodium In Phosphate Buffer: Since the buffer solution of sodium chloride, potassium phosphate and sodium phosphate is isotonic, it is used in a wide variety of applications in biochemistry. The chemical formula for sodium phosphate is Na3PO4. Also known as TSP or Trisodium Phosphate, it is a white crystalline substance easily available in stores and used for household applications like painting. Besides being used as a cleaning agent due to its degreasing properties, it is also used in food processing as an additive, acidity regulator, an agent in emulsions, and for thickening and metal chelating. It is also used in enemas as a laxative. Although sodium phosphate is used widely as a cleaning agent for domestic purposes, it can corrode metals and hence not considered appropriate for cleaning toilets. Sodium in phosphate buffer helps to regulate the pH of the saline solution.
Preparation Of Phosphate Buffer: The preparation of 10 liters of phosphate buffer requires the following chemicals in the stated proportions:
800 g of sodium chloride - NaCl
20 g of KCl
144 g of sodium phosphate dibasic - Na2HPO4
24 G of Potassium Phosphate - KH2PO4
8 liters of distilled water
Dissolve the chemicals in distilled water, and top up to 10 liters. The preparation of phosphate buffer according to the above mentioned method will yield a pH of 6.8.
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