Gas chromatography (GC) experts rely on sharp peaks and baseline resolution to provide accurate answers. To perform chromatographic analysis of real-world samples, analysts often must deal with either complex sample types such as essential oils and petroleum fractions, or complex matrices like biological fluids, foods, sludge, or polymers. Once the sample has been prepared for analysis, separation of all the individual compounds present in a single chromatographic separation can be challenging.
It is therefore necessary to use innovative yet robust techniques that go beyond using a single chromatographic dimension to achieve compound separation. This sounds simple, but until now it hasn’t been, since techniques that require a second dimension (column) require a lot of additional hardware, including an extra GC. An alternative is using comprehensive GC (GCxGC), however, this inevitably leads to large economic investments and huge data files which is a challenge of it own.
The patented GERSTEL Selectable 1D/2D-GC/MS System enables the best of both worlds. The system can be used for routine single dimensional GC/MS analysis without any additional complications. With the click of a mouse it can be switched to perform two-dimensional separation when needed for more complex matrices. This also allows interesting sections of the chromatogram to be collected and concentrated from multiple runs to better separate and isolate trace compounds. All this is performed using just one GC/MS system.
An example is food analysis which is certainly not a trivial matter. The typical matrix is complex, often requiring several sample preparation steps and extensive sample cleanup. However, even well prepared samples can produce loads of overlapping peaks. If a case of unresolved peaks is clearly at hand, or if an odor detected by using an Olfactory Detection Port (ODP) doesn’t match the peaks in the chromatogram, the user needs to have a good tool kit at her or his disposal. In this case, selectable multidimensional GC can be the technique that cuts through the thicket and provides clear, reliable answers whenever one-dimensional GC does not.
Both columns are installed on the same GC and heated independently using Low Thermal Mass (LTM) technology. The process of cutting a section of a chromatogram and introducing it to another column is called heart-cutting. Neither the GC run, nor analyte detection is interrupted during the run. Detection of the analytes that were transferred to the 2nd column uses the same detector(s) as used for the 1st dimension, in the same chromatogram and immediately after the end of 1st run.
We have the expertise to install and transfer the technology to your laboratory.
A typical procedure is:
A sample is injected into the system and is run on column 1, eluting directly to the MS. Specific areas of interest are chosen, the sample is run again, and the selected time-areas are switched (using the Deans switch) to the re-focusing point CTS2, cooled by LN2. After final elution of the components from column 1, the CTS 2 is heated and the trapped components chromatographed on column 2 and analyzed by the MS.