Ghost peaks, or gradient system peaks, are common challenges in liquid chromatography, especially during gradient separations with buffer salts. These unwanted peaks can interfere with analyte detection, making accurate analysis difficult.

The primary cause of ghost peaks during gradient operation is the accumulation of impurities with UV absorbance at the head of the column. Under low initial organic phase conditions, these impurities cannot be sufficiently eluted. As the organic phase proportion increases, these impurities are gradually released, creating "ghost peaks" on the chromatogram and complicating target analysis.

OneTwo Chromatography's Ghost Peak Capturing Column effectively captures and removes these mobile phase contaminants before they reach your analytical column. Acting as a protective barrier, this innovative solution minimizes ghost and gradient system peaks, allowing for clearer, more precise chromatographic results. This not only enhances analysis quality but also saves time and improves workflow efficiency.

Optimize your chromatography setup with the Ghost Peak Capturing Column—an essential tool for clear, reliable results in gradient separations.

Note:

The typical operational lifespan of this Ghost Peak Capturing Column is 800–1000 injections, though the actual lifespan varies with specific mobile phase conditions. It must be installed upstream of the injector—never downstream—to prevent irreversible sample adsorption.

In gradient elution, the low initial organic phase proportion, along with the dead volume introduced by this capturing column, may cause baseline disturbances. This typically appears as a baseline drop or "hump" in the early chromatogram phase (generally within the first 5 minutes). To address this, it is recommended to slightly increase the starting proportion of organic solvent in the mobile phase to at least 5%, or consider using a smaller column, such as the 4.0 × 30 mm dimension, to minimize baseline fluctuations.

This capturing column may cause minor delays in the elution of target analytes due to its dead volume, with retention time shifts typically within 1.0 minute. Variations will depend on mobile phase composition, as not all impurities are entirely removed.

When using mass spectrometric (MS) detection, this capturing column may contribute to baseline noise due to gradual elution. If ion-pairing reagents are present in the mobile phase, caution is recommended, as the column may irreversibly adsorb these reagents, potentially affecting target peak shape. This capturing column is designed for gradient mobile phase applications only and is generally unnecessary in isocratic conditions.

The capturing column’s end-of-life is indicated when previously eliminated impurity peaks reappear after multiple injections, signaling a need for replacement. Due to irreversible adsorption of impurities, this column cannot be regenerated for reuse.

For standard setups, a 4.6 × 50 mm Ghost Peak Capturing Column is suitable for analytical columns sized 4.6 × 250 mm or 4.6 × 150 mm, while a 2.1 × 50 mm capturing column is recommended for UHPLC columns of 2.1 × 150 mm or 2.1 × 100 mm.