We are extracting PVC compounds using diethylether. We analyse this extract directly on our GC-MS system. After analyzing this extract on our GC-MS, we observe an increasing baseline of the following injection (blanc acetone injection after sample injection). We suspect that the ESBO or the stearate could be the cause of this problem. After 24 ours this phenomenon has disappeared completely. The increasing sensitivity of the Mass Spectrometer decreases the area of our internal standard which ruins the quantification of the plasticizer.

Does anyone have a suggestion which parameter of the Mass Spectrometer could help to reduce this effect or what could be the cause of this phenomenon?