Basic Troubleshooting for GC Systems

Created by Agilent Knowledge Portal 9 months ago | Last modified by Carlos Vargas 9 months ago

This Information Applies To: Agilent GC Systems

Issue

Several problems can be identified in GC chromatograms, and each of these problems can have various different sources.

Regular maintenance of your instrument in accordance with the recommended maintenance schedule will reduce the incidence of chromatography problems.

Steps to follow

The most common gas chromatography problems identified in a chromatogram include:

Ghost peaks or carryover (Figure 1).
See Source of Ghost and Carryover Peaks in GC

Figure 1. Ghost and carryover peaks
1. Clean blank run (no injection), 2. Contaminated run with ghost peaks and carryover
Excessive baseline noise (Figure 2).
See Excessive Background Noise in GC

Figure 2. Excessive baseline noise
1. Normal background with peaks visible, 2. Excessive background with peaks partially obscured
Baseline instability or disturbances (Figure 3).
See Baseline Instability in GC

Figure 3. Baseline instability
1. Stable baseline, 2. Unstable baseline
Fronting peaks (Figure 4).
See Peak Fronting in GC

Figure 4. Fronting peaks
1. Normal symmetrical peak, 2. Fronting asymmetrical peak, 3. Overload
Tailing peaks (Figure 5)
See Peak Tailing in GC Systems

Figure 5. Tailing peaks
1. Normal symmetrical peak
Split peaks (Figure 6).

See Peak Splitting in GC

Figure 6. Split and broadening peaks
Retention time shift (Figure 7).
See Peak Retention Time Shift in GC

Figure 7. Retention time shift
1. Normal retention time, 2. Retention time increased
Change in peak size (Figure 8).
See Peak Size Changes in GC

Figure 8. Change in peak size
1. Some peaks change size, 2. All peaks change size
Loss of resolution (Figure 9).
See Loss of Peak Resolution in GC

Figure 9. Loss of separation
1. Normal retention time separation, 2. Separation, 3. Peak width
4. Decrease in separation, 5. Increase in peak width