1M Sodium Phosphate Dibasic is a 1 M stock of disodium phosphate in purified water. On its own it is mildly alkaline. The 500 mL fill suits bench-scale buffer preparation.

It is commonly used with its counterpart stock to prepare sodium phosphate buffers at a defined pH for chromatography mobile phases, protein handling, and conjugation reactions. Phosphate has no primary amines, so it suits NHS-ester chemistries. For 100 mM sodium phosphate at pH 7.0, combine about 39 mL monobasic and 61 mL dibasic stock per liter, then verify pH.