ph of mobile phase

[chilam]

Hi All,

I am developing hplc method for combination of buprenorphine and naloxone. I came across a article published in Talanta 2009.

Paper says Mobile phase consists of acetonitrile and 10mmol/L potassium phosphate buffer adjusted to pH 6 with orthophosphoric acid.

But when i prepare 10mmol /L potassiumphosphate buffer, i have to use base rather than acid to adjust pH to 6.

can you please help me how to prepare mobile phase ?

[paulw]

If you use a monobasic salt of phosphate you will have to use base to adjust. If you use the dibasic salt, you will need to use phosphoric acid to adjust. It looks as if the paper referenced the dibasic potassium phosphate and you used monobasic potassium phosphate.

[montana]

Hi,

For the preparation of 10mmol/L potassium phosphate buffer pH 6 , i recommand to see the European Pharmacopoeia :

4.1.3. BUFFER SOLUTIONS.

Good Luck