To prepare a 1 liter of 1x working solution PBS, put 100 ml of a10x PBS solution into the graduated cylinder or 1 L volumetric flask. Then, 900 ml of distilled water or adjust the final volume of the solution up to 1 L. The final solution is 1x PBS. The pH does not need to be adjusted as dissociation of water is very low and does not affect the pH of the solution.