This Information Applies To: Agilent GC Systems
Peak fronting is present in a chromatography peak when it has an excessive asymmetry with a leading 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.
Fronting can be caused by sample solvent, component concentration, injection conditions, column selection, and other reasons. Figure 1 shows no fronting, minimal fronting and excessive fronting.
Possible causes of peak fronting include:
|Possible cause of fronting||Solution|
|Column overload (component concentration too high)||
Dilute the sample, check that the correct volume has been injected, check the syringe size, decrease the injection volume, or increase the split ratio
|Improper injection technique (slow/erratic plunger depression)||Check that the syringe plunger is moving freely. The solution should be pulled into the syringe body (no solution left in the needle), and moving freely and fast when plunger is depressed. Use an autosampler|
|Component highly soluble in the injection solvent (Reverse Solvent Effect)||Change the injection solvent or use a retention gap|
|Mixed sample solvent with large differences in polarity or boiling points||Change the sample solvent|
|Improper column installation||Remove and reinstall the column. See Capillary Column Installation Quick Reference Guide|
|Column contamination||Bake out the column. Limit the bake-out for 1 to 2 hours
If these procedures have not resolved the peak fronting problem, contact Agilent Technical Support.
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