Preventing air bubbles in the HPLC system

The presence of air bubbles near the detector in the HPLC system often causes spikes in the chromatogram, which can occur in a peak and/on the baseline. They prevent peaks from being integrated properly and hence result in inaccurate analysis results.

The most common cause of air bubbles in the system is insufficient degassing of the eluents. Contrary to many claims, column damage caused by air is minimum as the eluents are pumped through the column at high pressure.

There are several methods for degassing. Vacuum degassing has proven to be most effective, compared to helium purging and other degassing methods. Another way to prevent air bubbles is to apply a low back pressure to the detector outlet using restriction capillaries and increasing the pressure at the column outlet.