The high mass resolution of IONICON’s PTR-TOFMS series can now be complemented by a fast gas chromatographic pre-separation step. The fastGC augments your data with another dimension of chemical information, allowing to separate isomeric compounds, while maintaining fast spectral runs.
In a gas chromatographic (GC) column, compounds are separated in retention time according to their chemical properties. In contrast to classical GC, spectral runs in less than one minute are possible with the IONICON fastGC module, providing near real-time data. The fastGC is an add-on for IONICON PTR-TOF systems and uses the same sample inlet. The fastGC mode can be activated when required while not affecting the regular PTR-TOF operation otherwise. It can also be used to eliminate the influence of high concentrations of matrix compounds, e.g. ethanol in beverages, and to study fragmentation and interferences.
The fastGC control software allows changing parameters, configuring temperature ramps, and to initiate (also repeated) fastGC runs. The software is tightly interconnected with the PTR-TOF operation software to synchronize fastGC runs and data acquisition.
For the FUSION Series, an improved fast-GC design and new electronics are available, which allow for more detailed information gain.
The fastGC option is particularly useful in food and flavor science. Researchers are often faced with two problems: 1) A few compounds, e.g. ethanol in alcoholic beverages, are present in high concentrations and dilution would be required, and 2) several isomeric compounds are of interest and cannot be resolved easily. Only the fast gas-chromatographic separation reveals the distinct differences in concentration of the isomers between the samples. Moreover, the high concentration of ethanol elutes the column at an earlier time and hence, does not affect the measurement of the compounds of interest compounds [Romano et al].
Monoterpenes are a group of biological VOCs emitted in high quantities by numerous plant species, particularly conifers and are associated with the typical scent in a forest. A PTR-TOF can record the combined contribution of these isomers, and – with the addition of the fastGC – the contributions of different monoterpenes can be monitored individually. Materić et al. have studies monoterpene emissions from different pine needles. The figure shows fastGC-PTR-TOF chromatograms of: a) Monoterpene standards, b) Norway spruce, c) Scots pine, and d) Black pine. More see [Materic et al.]
The separation and identification of the vast number of compounds present in biological samples poses a challenge even for high mass resolution instruments, such as PTR-TOF. The fastGC add-on can substantially improve this situation. This has been demonstrated by Ruzsanyi et al. for measurements of aldehydes emitted from skin and for compounds present in human breath. For these tests a prototype version of the fastGC using a multi-capillary column had been used.
