Many people ask me about the problem associated with polar acidic compound analysis using HILIC or ion exchange columns with Mass Spectrometry. Fortunately, there is an easy solution to this problem. You can use Cogent HPLC columns such as the Diamond Hydride, Phenyl Hydride and others to separate highly polar compounds in Aqueous Normal Phase (ANP) mode with better results. With ANP, you only need from 0.1mM to 10mM of ammonium acetate or other acids or bases to get great results.
This leads to many benefits such as minimizing MS inlet source build up of precipitated salt from using 20mM – 75mM as recommended by column suppliers. Also, too much salt in your mobile phase can cause ion suppression. This is avoided by adding the low amounts needed in ANP.
Below is an example of an MS Inlet that has been clogged by too much salt in a mobile phase.