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Articles Basic Troubleshooting for GC Systems
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  • Created :  10 Nov 2022
  • Modified :  6 Feb 2023
  • Category :  Agilent Knowledge Portal
  • Entry Type :  Article
  • Product Type :  GC Sample Preparation and Introduction GC Systems
  • Component :  Automatic Liquid Samplers Capillary Flow Technology GC Inlets GC System GC Valves GC Detectors Headspace Samplers PAL Autosampler Systems
  • Product Name :  6850 Automatic Liquid Sampler 6850 GC System 6890 GC System 7650A Automatic Liquid Sampler 7683 Automatic Liquid Sampler 7693A Automatic Liquid Sampler 7694 Headspace Sampler 7697A Headspace Sampler 7820 GC System 7890 GC System 8697 Headspace Sampler 8860 GC System 8890 GC System G1888A Headspace Sampler Intuvo 9000 GC System PAL 3 CTC Autosampler System PAL XT CTC Autosampler System
  • Task :  Troubleshooting
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Basic Troubleshooting for GC Systems

Answer

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

 Tip 
Learn how to effectively troubleshoot your Agilent GC System:
GC-0GEN-1040z - Practical Steps in GC Troubleshooting
GC-0GEN-2040zs - GC Troubleshooting Series e-learning courses available from Agilent education
 
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