Select-eV shaping the future of GC-MS (HTC-13, 2014 conference)
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Select-eV – Shaping the future of GC–MS Laura McGregor, Nick Bukowski
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21-Oct-2014 -
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Technology
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Presentation given at HTC-13 in Bruges, Belgium, on Markes' BenchTOF time-of-flight mass spectrometers for gas chromatography. As well as the features that make BenchTOF essential in the modern laboratory, the presentation describes Select-eV – newly launched variable-energy electron ionisation technology for GC–MS. Many examples are provided that illustrate how both classical reference-quality EI mass spectra at 70 eV and enhanced molecular ions at lower energies can enhance detection of challenging analytes – all without any loss in sensitivity.
Transcript of Select-eV shaping the future of GC-MS (HTC-13, 2014 conference)
Select-eV – Shaping the future of GC–MS
Laura McGregor, Nick Bukowski
• A reflectron time-of-flight mass spectrometer
• Platform-neutral
• Innovative design
What is the BenchTOF?
BenchTOF technologyInnovative design
High accelerating
voltage
Differentially pumped source and analyser chambers
Direct extraction optimises sensitivity
Multi-stage reflectronoptimises resolution
The result……exceptional sensitivity for trace analytes
RT: 3.50 - 5.65
3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6Time (min)
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5.23
4.47 5.484.50 5.194.33 4.683.723.60 3.86 3.95 4.22 4.95
NL:3.62E4m/z= 271.50-272.50 MS 100812_13_dbc_100812154612
Base Peak Retention Time : 5.23 Scan : 628 Intensity : 36173
Calculated values Noise Range : 3.99 - 4.19 minutes (24 scans) Baseline : 6 Signal To Noise : 2747 Standard Deviation : 13
OFN 1 pg
Exceptional sensitivityTrace-level pesticides (20 pg of aldrin; EIC m/z 263)
BenchTOFS/N ratio: 380
SIM quadrupoleS/N ratio: 41
2 pg on columnS/N ratio: 30
Variable-energy electron ionisation with no loss in sensitivity
Advantages of Select-eV ionisation
• No source exchanges or reagent gases
• No loss in sensitivity
• Enhanced molecular ions and reduced fragmentation
• No ionisation of carrier gas/background gases
• Reduction of matrix impact
Enhanced signal-to-noise and lower LoD for target analytes
Variable-energy ionisationTransition of fragmentation pattern aids structural elucidation
70 eV
16 eV
12 eV
Select-eV ionisation of alkanesPentacosane (C25H52)
14 eV
70 eV
Molecular ion: 1.5%(800 counts)
Molecular ion: 26%(4000 counts)
The full presentation can be downloaded from the Markes websitehttp://www.markes.com/Resources/Scientific-publications/Conference-presentations.aspx
