What is the difference between PBS and dPBS?

PBS and dPBS are the abbreviations of phosphate-buffered saline and Dulbecco’s phosphate-buffered saline, respectively. They are well-known buffer solutions that are commonly employed in biological research to maintain a consistent pH (between 7.2-7.6). The essential properties of both are that the ion concentrations and osmolarity retain their isotonic properties, meaning that the solutions are compatible with the human body. Although multiple formulations exist, the default for both will include sodium chloride (common table salt), and disodium hydrogen phosphate. Other ingredients, such as potassium chloride or potassium phosphate, may also be included in the formulation.

The substances can often be used interchangeably, although dPBS is typically slightly lower in phosphate concentration and may include calcium and/or magnesium. Experimental needs will dictate which solution should be employed.
For example, if in a particular experiment trypsin enzymatic activity will need to be measured, the calcium and magnesium sometimes included in dPBS might skew results, so simple PBS would be preferable.

To explore common buffer formulations, see Buffer Preparation and Recipes interactive in 'Additional Resources' below: