Hello all,

We have not used buffer in ouer mobilephase. However I am going to analyse compound were I think it would be good to avoid acid/base reaction.
Can someone give som hint on were I could find sutible chemicals?
Have seen that phosphate is comonly used, but is also interested in some citrate buffer.

Phosphate and citrate are commonly used buffers. The choice depends upon the pH at which you wish to buffer your mobile phase. Phosphate has pKa's at 2.1, 7.2 and 12.3; citrate at 3.1, 4.7 and 5.4. Acetate is 4.8.
Ordinarily in reverse-phase chromatography, you want to adjust the mobile phase pH to >2 pH units either side of the pKa of the analyte, depending upon whether you want the analyte protonated or not.
One warning: there's a lot of prejudice out there against citric acid. Some say it attacks the stainless steel in LC systems. I have used citrate for years without problem. Never leave any buffer in your system without flow. Also citrate does grow bacteria very well. It needs to be refrigerated and replaced frequently.

Be careful with phosphate buffers--the higher the pH, the better to strip the column with!!

ALso, If you're running basic compound(s), try to use pH buffers that are at least 2 pH units LESS than the pK of your compund(s). That will help to suppress the tailing due to silanol-interactions.
Of course, this is only if the manufacturer says that the pH you want to use is suitable for the column you have.