Enhanced aroma profiling of wine by GC–TOF MS with variable-energy ionisation
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Transcript of Enhanced aroma profiling of wine by GC–TOF MS with variable-energy ionisation
Enhanced aroma profiling of wine by
GC–TOF MS with variable-energy ionisation
38th ISCC & 11th GCxGC, Riva Del Garda
Markes International – vendor seminar
Laura McGregor1, Luca Calamai2,3 Steve Smith1 and Nick Bukowski1
1. Markes International, Gwaun Elai Medi-Science Campus, Llantrisant, RCT, UK
2. Centro Interdipartimentale di Servizi di Spettrometria di Massa, Via U. Shiff 6, 50016 Sesto Fiorentino , (FIrenze)
3. Dip. Scienze delle Prod. Agroalimentari e dell’ambiente (DISPAA), Univ. degli studi di Firenze, Piazzale Cascine 28,
50144 Firenze
Wine aroma is a complex combination of a wide
number of simple sensory perceptions
What gives wine it’s characteristic aroma is...
Source: zinfandel.org
… A combination of many different volatile compounds typical of each wine
Off odours
Approaches for characterising wine aroma
Sensory vs. Analytical
Source: www.arcus.no
sensitivity
Major Drawbacks
Major Advantages
sensitivityreproducibility
Uses sensory descriptors and their intensity as assessed by
Use compounds identification and quantification by
reproducibility
Panel test (5-30 members)HS–(GC)–MS analysis
Analytical approach for studying wine aroma Headspace–SPME sampling
15 min
1 mL wine 4 mL water
2 g NaCl40 uL ISTD mix
60 ºC
DVB/carboxen/PDMS fiber (50/30 µm).
GC–TOF MS
BenchTOF-Select:Data rate: 4 HzMass range: 30–450 amuIon source: 200 ºCTransfer line: 260 ºCIonisation energy: variable
GC Oven:40 ºC for 1.0 min,2 ºC/min to 60 ºC3 ºC/min to 150 ºC10 ºC/min to 200 ºC 25 ºC/min to 250 ºC (hold 10 min).
Column: HP-Innowax (50 m × 200 µm × 0.4 µm)Injection:Splitless, 260 ºC.
Quantitative approach: Calibration Standard mix
• The calibration standard mix spanned a wide range of target compounds prepared in same way as for wine aroma profiling (SPME) but using a 12% ethanol solution containing 0.5% tararic acid as a wine mimic matrix instead of 1mL of wine
• Target compounds from 5 chemical classes:
– Esters
– Lactones
– Aldehydes & Ketones
– Alcohols & Terpene alcohols
– Acids
• Internal Standard compounds: two deuterium-labelled compounds or surrogate absent in samples for each class
Results
Calibration standard with wine mimic matrix
Ethyl acetate
Isoamylacetate
2-methyl-1-propanol
Isoamylalcohol
Ethyl hexanoate
Hexyl acetate
Hexanol
Ethyl octanoate
Benzaldehyde
Decanoicacid
Ethyl
decanoate
Octanoicacid
The full presentation can be downloaded from the Markes websitehttp://www.markes.com/Resources/Scientific-publications/Conference-presentations.aspx
Conclusions
• Low energy ionisation aids identification and extends LoDs
• Low energy ionisation aids identification and extends LoDs
• 70 eV and 14 eV give comparable quantitative results
• GC×GC allows additional compounds to be identified
– Off-odours
– Fungicides
– Compounds at ultra-trace level
Case study 2:
Enhanced screening of environmental pollutants in complex matrices by GC××××GC–TOF MS
A collaboration with…
Water Framework Directive (WFD)
• Lower detection limits
• New monitoring methods and analytical techniques are now necessary
• Focus is on “priority” substances, but what about those of emerging concern?
Conclusions & Further Work
• Promising start to the project; Select-eV adds an extra dimension of information
• Quantitation of POPs required
• Compare local drinking water/pollution levels with prosthesis extracts
Acknowledgements
• Anthony Gravell (NRW), Ian Allan (NIVA) and
Graham Mills (Portsmouth Uni)
• N. Bukowski, G. Davies, D. Barden and S. Smith,
Markes International
• Luca Calamai, University of Florence
The full presentation can be downloaded from the Markes websitehttp://www.markes.com/Resources/Scientific-publications/Conference-presentations.aspx
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