Cogent TYPE-C Silica™ columns and ANP methods keep your MS source cleaner than HILIC methods

Does this situation look familiar?

Corroded Ion Source for Agilent TOF when used with HILIC Columns

It’s a common problem for many of us working with LC-MS and with polar compounds in particular. Our method calls for a mobile phase with a high concentration of buffer, and bam, your MS source quickly becomes contaminated (60 mM concentration and 500 injections in this case). The frequent required cleaning of the ion source reduces our throughput and takes up valuable time. What can we do to avoid problems like this?

The solution is to avoid using these high salt concentrations. The Cogent TYPE-C Silica™ materials allow you to do this by way of a aqueous normal phase (ANP) retention. Due to differences in the stationary phase properties compared to HILIC columns, a high salt mobile phase is simply not required. Typically we use 5–10 mM buffer where a HILIC column might require 50 or 60 mM for the same compounds. What this means for us the chromatographers is that the MS ion source will not be contaminated with salt precipitate as readily due to the lower concentration.  More uptime!, Less costs!

The difference is due to the stationary phase being more polar in HILIC phases than Cogent columns. Therefore a higher amount of salt in the mobile phase may be needed in HILIC to get compounds that are retained on the stationary phase to elute in a timely manner. By the way, this is also a great feature when doing prep HPLC as well.

Save yourself from a few headaches and try one for your next LC-MS method! You will be pleasantly surprised with the results!