During HPLC analysis, especially when employing gradient elution, some unexpected peaks (usually called “Ghost Peaks”) may appear in the chromatogram. These unwanted peaks often coelute with analytes of interest. Welch Ghost-Buster Columns can effectively remove organic impurities with low polarity, without changing the composition of the mobile phase and thus prevents interference from ghost peaks. It is installed between the gradient mixer and injector, which helps remove impurities in the mobile phase and also in the mixer and pipelines as well.