Norwegian Mass Spectrometry meeting / Hafjell 2019

januari 8, 2019

Under NSMS möte på Hafjell / Lillehammer deltog ca 160 personer. Fint väder, bra skidbackar med väl preparerade pister, god stämmning och bra blandning av social samvaro och vetenskap.

Detta är något som vi i många år försökt kopiera men misslyckats med.
Takk for sist neste møte på Hafjell 2021.

Chemalys presenterte to plakater.

Reliable speciation of fatty acid methyl esters (FAMEs) by flow-modulated GC×GC-TOF MS/FID with Tandem Ionisation

Jan Nordin1, Laura McGregor2, Keith Summerhill3, Aaron Parker2, Bob Green2 and Albert Koulman3,4

1Chemalys, Dalarö, Sweden 2Sepsolve Analytical, Peterborough UK  3MRC Elsie Widdowson Laboratory, Cambridge UK 4NIHR BRC Nutritional Biomarker Laboratory, University of Cambridge, UK.

Triglycerides of fatty acids are major components of the fats and oils present in foods and living organisms, and along with fatty acids themselves, play a central role in human health. Research into both these areas relies on knowing the chemical structure of the fatty acid side-chains (specifically the chain length, degree of unsaturation and double-bond stereochemistry), and the proportions of particular classes of triglycerides present.

Analysis of fatty acids is therefore an area of considerable interest. To avoid reproducibility problems in the analysis of free fatty acids, it is common to extract the lipid fraction from the substrate and convert it to the corresponding mixture of fatty acid methyl esters (FAMEs). These are volatile enough to be analysed by gas chromatography (GC), typically with flame ionisation detection (FID).

However, the separation of FAMEs is challenging and none of the conventional solutions are ideal – longer columns are not only expensive but also lead to longer run times, while multiple runs and extra extraction steps decrease productivity.

Addressing such issues, two-dimensional gas chromatography (GC×GC) using two columns of differing selectivity can provide the chromatographic resolution necessary to separate larger numbers of unsaturated and saturated FAME homologues and isomers, in a single run.

In this study, we describe the benefits of GC×GC with parallel detection by time-of-flight mass spectrometry (TOF MS) and FID. This includes confident identification of targets and unknowns through the use of Tandem Ionisation for simultaneous acquisition of 70 eV and soft ionisation mass spectra

Aroma profiling of pet food using high-capacity sorptive extraction and TD–GC×GC–TOF MS

Jan Nordin1, Laura McGregor2, Aaron Parker2, Bob Green2 and Nick Bukowski2

1Chemalys, Dalarö, Sweden 2SepSolve Analytical, Peterborough, UK 

Pet food manufacturers place great importance on the aroma of their products, as off-odours may be unappealing to both the pets and their owners. Confident identification of the volatile organic compounds (VOCs) from pet food can help these companies better understand the factors governing the release of pleasant and unpleasant aromas. VOC aroma profiles are typically analysed by solid-phase micro-extraction (SPME), which although a fast and simple technique, can be limited in terms of sample capacity, reproducibility and sensitivity.

An alternative to SPME is high-capacity probe-based sorptive extraction, which results in higher sample loadings because of the large volume of PDMS phase. Typically, a SPME fiber has a sorbent volume of just 0.5 µL, while the sorptive extraction probes used in this study contain 65 µL of sorbent. When used in conjunction with secondary refocusing by thermal desorption (TD), the result is greater sensitivity across a wide analyte range.

Further analytical benefits can be achieved for analyte separation and detection, by using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC–TOF MS). The enhanced separation capacity of this approach is ideal for handling the complex aroma samples of pet food, because it allows the entire composition to be screened in a single analysis, with confident identification of compounds that would ordinarily co-elute.

Here we demonstrate the value of high-capacity sorptive extraction with TD–GC×GC–TOF MS to investigate the volatile compounds present in the headspace of pet food, and discuss how these compounds might influence their aroma profiles.