If an analysis shows peaks that are not symmetrical, where the top of the peak is shifted to the right and then drops off steeply, check the following possible causes. This symptom is most likely with splitless injections. This is sometimes referred to as overloading because is frequently caused by a large injection that overloads the liner and column.
The analyte concentration is too high for the film thickness of the current column. Make sure the analyte concentration and column film thickness are compatible.
Increase the initial oven temperature by 10 or 20 degrees C and see if the fronting decreases.
Active sites can cause a number of symptoms. The most common symptom is peak tailing. Others symptoms include peak fronting and increased retention times.
Replace the injection port liner with a new, deactivated liner.
Make sure the liner is installed properly. Column fragments in the liner can cause peak tailing.
Replace the injection port seal.
Remove the column from the injection port. Break off the first 10 cm. Reinstall the column in the injection port.
See the documentation supplied with the GC for help with injection port maintenance.
If the injection expands to a volume greater than the volume of the liner, it can skew the peak to the left (peak tailing) or right (peak fronting). Decrease the injection size.
An injection port temperature that is too high can cause fronting. Reduce the injection port temperature 25 to 50 degrees C and try again.