Causes and Measures for Addressing Ghost Peaks in Reversed Phase HPLC Analysis

One of the brain-racking challenges in LC analysis is the presence of ghost peaks. Ghost peaks are of unknown origin in a chromatogram, are easily misidentified when they are close to peaks of interest, and can result in quantitative errors when they overlap peaks of interest. Uncertainty in data quality and reliability is of course the result. To make matters worse, considerable time can easily be expended in determining the source of an apparent impurity, even if there is none associated with the compound of interest. With the increase in UV detector sensitivity that has come about in recent years, detection has become possible at very low concentrations, bringing the problem of ghost peaks into the spotlight. In this report, we focus on the source of ghost peaks in reversed phase analysis using a UV detector, and propose various remedial measures that can be effective.