If the peak tailing is occurring in the peaks closest to the solvent front then this type of effect is called reverse solvent effect. This effect can be minimized by using a guard column of same dimension as your main column.

1. Your solvent should earlier vaporize then your compounds, also check your injection parameters and your temperature programm.

2. If all your compounds are tailing somthing is wrong with your GC - do troubleshooting!

http://www.detroitsection-acs.org/optimize.pdf

good luck

If you consider a mixture where the main component ( witch could be the solvent) is has a long retention time and you inject this on a column -assume no injector problems- you could end up in a situation where a significant area of the column is occupied by this component as a consequence :

- you have less original stationary phase

- the unwanted film can interact with other analytes and retain a portion of them longer .

I recently had an example where the amount of a major component changes the retention time of the analytes eluting nearby. In this case increasing the initial temperature was a part of the solution

Thanks, Kris, this clears things up. I had suspected something to do with physical displacement of the analyte but was not sure how to articulate this.

Thanks for your input, Rajeev and Christian, but I was more looking for an explanation of the cause. The reverse solvent effect is not always easily avoided: I am extracting my analyte from live microbial cultures during fermentation using a non-polar second phase. This boils later than the analyte so must be diluted into another solvent before injection on the GC. Because the original extraction solvent is still abundant after dilution it still exerts a reverse solvent effect on the analyte, even though it is not the "main solvent" in the injection. In this situation I find the peaks can usually be compressed by trialling different dilution solvents.