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™ columns while 25mM can be used with columns based on type B silica.