I have continued my GC-MS measurements during the last 2 weeks and I have come up with some encouraging results.
First of all I have modified the inlet with a special SPME liner (with a low diameter and volume for splitless injection) that should improve peakshapes – and it indeed does. My peaks are sharper and better separated, which is good, because I still have a considerable number of peaks that are bleeding (although a lot fewer since the replacement of the liner).
As a result, some of the compounds that I could not detect in previous runs (or just a few fragments indicating their presence) are now appearing more clearly. I could identify 1- and 1,2-chlorobenzene, toluene and some other compounds in my urban samples, confirming results from last year’s measurements.
The downside is that I am not quite there yet. Levels seem to be a lot lower than last year, which needs to be explained (e.g. snow properties,…) and some compounds, which I should find due to the heavy traffic just off-campus, still have not turned up.
