Stock solution A

0.2 M monobasic sodium phosphate, monohydrate (27.6g/L)

Stock solution B

0.2 M dibasic sodium phosphate (28.4 g/L).

Mixing an appropriate volume (ml) of A and B as shown in the table below and diluting to a total volume of 200 ml, to make a 0.1 M phosphate buffer of the required pH at room temperature. To make a 1 M phosphate buffer starting with 2 M A and B stocks.