Evaluating the authenticity of brand perfumes using GCxGC-TOF MS

In recent years, there has been a substantial rise in the number of counterfeit and imitation fragrances on the market that are sold at significantly lower prices compared to luxury brands. The packaging of such products is often so similar to the known brands that consumers may be unable to distinguish between genuine and fake goods.

It is therefore important to have confident quality and authenticity testing, to ensure consumers do not receive an inferior product, to protect brand reputation and minimize loss of revenues. This on-demand webinar, presented by Dr. Laura McGregor, product marketing manager at SepSolve Analytical, shows how the comprehensive data acquired using GC×GC–TOF MS, coupled with easy-to-use chemometrics software, can deliver fast and confident fragrance profiling.

Think you’d benefit but missed the live event? Register now to watch the webinar at a time that suits you and read on to find highlights from the live Q&A session.

Q: Can you explain more about how Tandem Ionisation^® works?

LM: Tandem Ionization is underpinned by our original Select-eV^® ion source technology. In this, we optimized the ion source design to be able to run it efficiently at lower ionization energies. The design means that even at low ionization energy, the electrons are efficiently channeled away from the filament and drawn into the ion source. If you were to try this on any other GC-MS, the lower accelerating potential is insufficient to draw electrons into the ion chamber and results in clustering of electrons around the filament. This ‘space charge limitation’ causes a drop in sensitivity by multiple orders of magnitude.

The patented Select-eV design means that we can achieve improved performance for soft electron ionization (EI), while the patented switching, known as Tandem Ionization, means that we can achieve both hard and soft ionization in a single run. If you want to find out more about that, we have a technical note on our website that goes into all of the details about Tandem Ionization and explains (with diagrams) how the ion source design improves the performance for soft EI.

Q: What ionization energies can be used on the system?

LM: With Tandem Ionization, we can select any two ionization energies between 10 and 70 eV. An autotune is simply run for the two ionization energies you want to use, and that can even be included at the start of a sequence. There are no hardware changes or additional parameters to optimize, it is all controlled by the software and all in an automated sequence.

Q: I analyze fragrance mixtures in scented candles. How could something be done using your system?

LM: On the system I showed in the slides, we were using our sample preparation robot (or SPR). Obviously, we used liquid injection in this case because of the neat perfume samples we were looking at, but the SPR can also be fitted with modules for headspace or SPME analysis to cope with solid samples, like candle wax. However, we also frequently use thermal desorption (TD) technology from our sister company, Markes International. For the analysis of solid samples like candle wax, we could also apply the Centri^® sample extraction and enrichment platform, where we can perform automated headspace sampling, SPME, or sorptive extraction and benefit from trap-based focussing to improve chromatography or to enrich the sample. Additionally, the Centri can accommodate tube-based thermal desorption, meaning that there would even be the option to sample indoor air onto TD tubes and monitor the impact of the scented candle – it’s one platform for liquid, solid and gaseous samples.

Q: Is there any way for the software to identify a series of compounds like aldehydes within my sample?

LM: Yes, within the ChromSpace^® software that I showed in the slides, we have a tool called Compound Explorer. This allows complex chromatograms to be filtered down to show only the peaks that have a certain characteristic. For example, if you were interested in aldehydes, the filtering expression could be prepared to look for ions or ion ratios that are characteristic of that class. When it is run, a filtered chromatogram is created which only shows peaks with those characteristics - in other words, only the peaks that have passed the expression are shown, making it much more selective than a simple EIC chromatogram. The expressions can be made as complex or as simple as required. The filters can even be used for things like neutral losses from the molecular ion, such as ethyl, methyl, or water losses. You can also use narrower mass tolerances in the expressions to make use of the improved mass accuracy of the BenchTOF2, so it is quite a powerful tool to quickly find a particular compound or a class of interest within a complex sample.

Find out more about the value of GC×GC for fragrance profiling in this on-demand webinar>>