The following table shows a list of common buffers and their working buffer ranges:


Buffer pH Range
Trifluoroacetic acid (TFA)  1.5-2.5
Phosphoric acid/monobasic phosphate (pKa 1)  1.1-3.1
Formic acid/formate  2.8-4.8
Acetic acid/acetate  3.8-5.8
Mono/dibasic phosphate (pKa 2)  6.2-8.2
Ammonia  8.2-10.2
1-methylpiperidine  9.1-11.1
Triethylamine  10.0- 12.0

As for concentration, about 5mM is suitable for Cogent TYPE-C Silica™ HPLC Columns while 25mM can be used with columns based on type B silica.