Many people uses carbonate buffer, basic pH, which is indeed called coating buffer (I dont remember the exact formula, but it should be easy to find it in the web). Others (like me) always use phosphate buffered saline, pH 7.4 (PBS) to coat the antibodies , on both Maxisorp and PVC plates. In 99% of the cases both work pretty well.

Some antibodies (very rare) need pH optimization to find the right coating conditions. I had one antibody that could only be coated at a pH rather acid, but this is extremely unfrequent.

In my lab we are using this buffer:

3.03 g Na2CO3,

6.0 g NaHCO3

1000 ml distilled water

pH 9.6,

I cannot say that this is the best, but we never faced any problem.

All the best

Yea, ACP-ELISA, i recommend coating buffer to add antigen according to DSMZ: It works perfectly for us

Coating buffer (pH 9.6):

1.59 g sodium carbonate (Na2CO3)

2.93 g sodium bicarbonate (NaHCO3)

0.20 g sodium azide (NaN3)

Dissolve in 900 ml H2O, adjust pH to 9.6 with HCl and make up to 1 l.

While to add Antibody,

Add 100ul per well of antibody (depending on the titer of the Antibody) in

Conjugate buffer: PBST + 2% PVP + 0.2% egg albumin (Sigma A-5253)

For reference: see DSMZ protocol for ELISA online

All the best.