I have a bit of confusion. I need to make 0.2M NaOAc buffer (as per the papers I am following). Now there are 2 different recipes of "sodium acetate buffer" available and that has got me confused. One is straight forward, following CSHL protocols
Sodium acetate buffer (0.2 M, pH 5.0)
Reagent Quantity (for 2 L) Sodium acetate trihydrate 54.43 g Glacial acetic acid 12 mL H2O
Now that is perfectly fine for me (except that I need pH 3.5-4.0 so all I need to do is to add a bit of extra acetic acid)
But here's another recipe
"Acetate buffer pH 3.6–5.6 Stock solutions A: 0.2 M solution of acetic acid (11.55 mL in 1 L distilled water) B: 0.2 M solution of sodium acetate (16.4 g of C2H2Na or 27.2 g of C2H3O2Na.3H2O in 1 L distilled water) x mL of A plus y mL of B, dilute to a total of 100 mL with distilled water."
(have found the same recipe in one of the old book on buffers available in print in our lab)
Apparently, people in my lab who have worked previously on similar experiments have used this later recipe while calling it 0.2M NaOAc buffer. In my opinion this (later) recipe cannot make a 0.2M buffer solution, it's something else. Papers other than our own group have usually used the specific term "0.2M NaOAc buffer (pH xyz)". Wondering what these other people are calling as NaOAc buffer?
Can someone explain what am I missing here?