A chromatogram is the detector response plotted against time. Each peak represents a component reaching the detector after travelling through the analytical path.
It is one of the most useful windows into analyser condition because it shows both the process result and the health of the separation.
Retention time
Retention time is the elapsed time between the start of the analysis and the peak maximum. It helps identify each component and confirm whether the separation is happening as expected.
A shift in retention time often points to changes in flow, temperature, timing, or column behaviour.
Peak area and peak height
Peak area is commonly used for quantification because it reflects the total detector response for the component. Peak height can also be useful, especially when reviewing narrow or fast peaks.
Symmetrical and well-resolved peaks usually indicate healthy separation. Tailing, fronting, broad peaks, or overlapping peaks often indicate developing problems.
Peak shape problems can come from sample contamination, valve leakage, poor timing, incorrect carrier conditions, or column deterioration.
How to review a chromatogram well
Do not look only at the final numbers. Review the baseline, retention pattern, resolution between key peaks, and any changes from previous good runs.
Trend review is often more valuable than a single snapshot because small changes appear earlier in the chromatogram than in the final report.
