dispatches from RAFA 2015, Prague
HRAM mass spec can take testing to another level – Thermo Scientific
The firm said its Q Exactive GC Orbitrap GC-MS/MS combines gas chromatography (GC) and high-resolution/accurate-mass (HR/AM) Orbitrap mass spectrometry.
It is for sample characterization and targeted and non-targeted analysis of contaminants and residues such as pesticides. We spoke to the company earlier this year about the machine.
Thermo Scientific presented a seminar on the subject at RAFA featuring presentations by Professor Jana Hajslova, University of Chemistry and Technology (UCT), Prague; and Dr Marc Tienstra, RIKILT, Netherlands and use of the instrument in food safety applications.
Professor Hajslova presented the Q Exactive GC for the profiling of extracts of whisky samples.
She addressed the importance of parameters such as high resolving power, mass accuracy, linear dynamic range and automated deconvolution of HRAM spectra for the analysis of chemical components present at high and low concentrations.
After the seminar, FoodQualityNews spoke to Richard Fussell, global vertical marketing manager, food and beverage, at Thermo Scientific.
Fussell said it is only a proof of concept study at the moment because it is based on relatively few samples.
“But quite clearly the technology enables you to distinguish between whiskies produced in different distilleries, even whiskies produced in the same distilleries at different times or ones that have been aged in different kinds of casks,” he told us.
“It seems to be you can separate the origin of the sample, so that is very important because it is a high value product and it could be prone to fraud or mislabelling.”
Holistic approach and past methods
Fussell said after the horse meat issue there’s a lot of emphasis on more holistic approaches and analyses to detect frauds immediately.
“So it is not just about detecting individual compounds, the analysis is moving more towards you gaining as much information as possible from the sample. Then you start to try and interrogate the samples with statistical analysis and if you have reference samples and you can use that for the quality control of products.
“The test needs to be very quick to be effective, almost testing in real time. The future could be that research laboratories will look at trying to use the technology like the Q Exactive GC and techniques such as Q Exactive coupled to LC in order to get all the information to be able to ensure that samples on the market aren’t contaminated or mislabelled.”
In the past the analyses were completely targeted, according to Fussell.
“Targeted analysis means that we asked the question are these specific list of analytes present in the sample.
“The problem is there will be other compounds, contaminants and residues in the sample that will not be detected using the targeted methods.
“Now, the Q Exactive Orbitrap and GC system gives us the ability to do a non-targeted acquisition so we can collect all of the information all of the time. In the case of mass spectrometry we are collecting all of the ions from the compounds that will chromatograph and ionise in the system.
“So that means we acquire a lot more information so the data files are more information rich. But that also means we have more information to be able to process so then the data processing is also extremely important. The benefits are that we can screen for many more analytes in the samples.”
Fussell said an approach could be taken whereby all compounds in the method are included which are expected to be found.
“Using full scan acquisition you can quantify and identify the compounds you expect to find but then in addition to that you can screen the data files against the library or the database to find compounds which you don’t expect to find, but which could still be present in the sample,” he said.
“Those data don’t have the same degree of quality control, you do have to validate the method and you do have to do the quality control, but the point is the methods are more efficient because with the targeted methods you do the quality control for all the compounds in the method.
“So if you have a targeted method for 200-300 compounds and if you only ever find 50-60 you have spent a lot of effort in trying to quality control compounds which you probably hardly ever find.”
Fussell said in the past 10 years there had been ‘really significant developments’ in the capabilities of instrumentation.
“I think that these developments in instrumentation are actually enabling the food chemists and the scientists to be able to undertake more holistic and more accurate analysis of foods. Both in the number of compounds we can analyse and also dealing with more complex matrixes,” he told us.
“The development in the instrumentation has also been facilitated by developments in the sample preparation steps of the methodologies as well which means that we can analyse the samples with lesser amount of solvent so it is a greener approach and also it means we can have a higher throughput, the steps are faster so we can analyse more samples each day.
“Sample preparation methods now are simpler and more generic which means that we can analyse compounds over a much wider polarity range so we capture more compounds in a single analysis.
“But also because of the simplicity of the methods the extracts are relatively dirty because they also extract more matrix components. Now we analyse more crude extracts with more sophisticated instruments so that does cause a problem sometimes because it can result in contamination of the instrument.
“So still there is some element of clean-up but it is dependent on the type of sample and the needs of the analysis so it is almost a case-by-case basis, it is down to the expertise of the food chemist.”
Research is being undertaken in the big laboratories using sophisticated instrumentation and trying to find marker compounds, said Fussell.
“From that and translating it to more handheld devices will be next so that some of these tests could be undertaken at the factory or the food producer level.
“These methods won’t replace the targeted analysis, there will be a need to do targeted analysis still, but there will be an increase in the use of methods that use profiling techniques in order to tackle issues such as fraud and even to look for multiple different kinds of contaminants in the same analysis as that is more efficient.”