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  • Category :  Agilent Knowledge Portal
  • Entry Type :  Article
  • Product Type :  GC Sample Preparation and Introduction GC Systems
  • Component :  Automatic Liquid Samplers GC Inlets GC System 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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Peak Tailing in GC Systems

Answer

This Information Applies To: Agilent GC systems

Issue

Peak tailing is present in a chromatography peak when it has an excessive asymmetry with a trailing edge. A normal peak is almost symmetrical.  

Other chromatographic problems are identified in  Basic Troubleshooting for GC Systems . Regular maintenance of your instrument in accordance with the recommended maintenance schedule will reduce the incidence of chromatography problems.

Background

Tailing can be caused by several reasons. Figure 1 shows some examples of peak tailing at several degrees. 

          
Figure 1. Peak tailing
1. Symmetrical peak with no tailing 

Resolution

 Tip 
Tip: Some active compounds always tail. 

 

Possible cause of tailing Solution
Split ratio too low  Increase the split ratio
Column contamination Bake out the column. Limit the bake-out for 1 to 2 hours or until the signal is stable
 Caution
Caution: Do not exceed the manufacturer recommended maximum column temperate limit as it will damage your column.
Trim the column: Remove 0.5 to 1 m from the front of the column 
Column activity Irreversible. Replace the column
Improper injection technique (slow/erratic plunger depression) Check that the syringe plunger is moving freely. The solution should be pulled into the syringe body, and moving freely and fast when plunger is depressed
Improper column installation, including poor column cutting Remove and reinstall the column. See Capillary column installation quick reference guide 
Solvent effect violation for splitless or on-column injections Lower the oven start temperature
Mixed sample solvent with large differences in polarity or boiling points Change the sample solvent or use a retention gap


If these procedures have not resolved the peak tailing problem, contact Agilent Technical Support.

 Tip 
Learn how to effectively troubleshoot your Agilent GC System:
 
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