Solubility of common buffers in Methanol

Buffers can cause various problems in the lab. Two common problems include surprising rises in HPLC-MS backpressures when starting the instrument after overnight storage and difficulties with MS sensitivity. Warning: do not use incompatible buffers with MS!

Increased instrument backpressure when using e.g. ammonium phosphate is a common problem found on chromatography forums, especially when the instrument was standing overnight or on the first few runs of each day. High soluble aqueous buffers can cause a great deal of head scratching. They become problematic in practical use, blocking capillaries, pre-columns, and analytical column end frits.

Potassium phosphate, Ammonium phosphate in Methanol

Credit: LCGC NORTH AMERICA VOLUME 22 NUMBER 6 JUNE 2004, Adam P. Schellinger and Peter W. Carr