Possible Cause | Prevention/Solution |
Ghost Peaks | |
Contamination in column or injector | Use only HPLC-grade solvents Flush column to remove impurities Flush injector between analyses |
Late eluting peak from the previous injection | Extend run time A flush column with the strong mobile phase at the end of each run For gradient runs, end at a higher concentration |
Contaminated water in RP HPLC | Use HPLC-grade water |
Unknown interferences in the sample | Use sample clean-up (e.g. SPE) |
Negative Peaks | |
The refractive index of solute is lower than that of the mobile phase (RI detector) | Use mobile phase with a lower refractive index Reverse detector polarity to obtain positive peaks |
Absorption of solute lower than absorption of mobile phase (UV detector) | Change UV wavelength Use mobile phase with lower UV absorption |
Sample solvent and mobile phase differ in composition | Change sample solvent and dissolve sample in mobile phase if possible |
Spikes | |
Air bubbles in mobile phase | Degas mobile phase Install back pressure restrictor at detector outlet Ensure all fittings are tight |
Column stored without endcaps | Store columns with endcaps Flush RP column with degassed methanol |
High-Performance Liquid Chromatography (HPLC) is a powerful analytical technique widely employed in laboratories for the separation, identification, and quantification of compounds in complex mixtures. However, HPLC analyses are not always as straightforward as they may seem. Analysts often encounter puzzling phenomena that can disrupt the accuracy and reliability of their results. One such enigma in the realm of HPLC is the occurrence of "Ghost Peaks."
Ghost Peaks, like spectral apparitions in chromatographic data, manifest as unexplained and unwanted peaks that can confound even the most seasoned chromatographers. These elusive peaks can compromise the integrity of analytical results, leading to inaccurate quantification, extended analysis times, and instrument downtime. To demystify the spectral hauntings in HPLC chromatograms, it becomes imperative to delve into the intricacies of what exactly Ghost Peaks are and how they can be effectively troubleshooted.
In this comprehensive guide, we embark on a journey to unravel the mysteries of Ghost Peaks in HPLC. We'll explore the origins of these spectral anomalies, examine the potential sources that give rise to their apparition, and delve into the intricacies of troubleshooting strategies aimed at banishing these chromatographic ghosts. Whether you are a novice chromatographer seeking to understand the nuances of HPLC or an experienced analyst grappling with unexpected peaks haunting your chromatograms, this guide aims to provide valuable insights and practical solutions to help you navigate the spectral realm of Ghost Peaks in the world of High-Performance Liquid Chromatography.
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Troubleshooting HPLC Ghost Peaks
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Chromatography
