| Abstract: | The analysis of complex mixtures, such as essential oils requires high resolution chromatographic separation and even the use of very efficient columns cannot prevent the overlapping of certain peaks. This means that it is very difficult to obtain high quality mass spectra when the sample contains numerous constituants. The pre-separation by column or preparative GC leads to a considerable loss of material and, often, to the formation of artefacts. In order to overcome some of these difficulties, we have built a simple multi-column system that is connected to an MS-MS instrument. Two independent chromatographs equipped with capillary columns were connected. The interface, which consists of a modified PTV injector, gives the possibilities of direct transfer, back-flushing, heart-cutting, intermediate cold trapping, trace enrichment and selective sample introduction. These operations are controlled by a switching valve system (DANI-MFC 393 unit). The chromatographic system was first connected to a MS-MS instrument which may result in high MS and collision activated MS spectra. |
