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17 Cards in this Set
- Front
- Back
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What's the principle of chromatography? |
Mobile phase carries molecules and passes through stationary phase |
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What is separation in chromatography based on? |
Differential interaction between mobile and stationary phase |
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What can you separate with size exclusion chromatography (HPSEC)? |
Oligomers and polymers (based on molecular weight) |
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What can you separate with ion exclusion chromatography? |
Organic acids (SCFA and ethanol content) |
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What can you separate with anion exchange chromatography (HPAEC)? |
monomers/ oligomers (carbs composition) |
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What size of molecules come through the column first in HPSEC? (Size exclusion) |
Big ones |
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What size of molecules go through column first in HPAEC? (anion exchange) |
Based on charge - small molecules first |
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What size of molecules go through column first in ion exclusion chromatography? |
Based on charge - only compare to standards to know |
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What mass spec does? |
Identifies molecules based on mass |
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What's the order of events in GCMS? |
sample (volatiles in headspace) -> fibre (volatiles stick to it) -> GC column -> to MS via transfer line -> detector --> software |
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What's solid phase micro extraction (SPME)? |
Used to concentrate volatiles in headspace before GCMS analysis |
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Which molecules move fast and which ones move slow in GC? |
Slow - if they are abundant in stationary phase Fast - more abundant in gas phase |
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Do you need different fibers for different stuff analysed? |
Yes - different peak images for different types of fibres obtained! |
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Which compounds contribute most to beer flavour? |
Esters |
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Beet fermentation- why lass raffinose if starter of L. plantarum used? |
L.plantarum produces alpha galactosidase which breaks down sugar |
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Why geosmin compound decreased in beets after fermentation? |
It reacts with acid to form argosmin |
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What happens to molecules during MS ? |
They are electrically charged Accelerated through magnetic field Broken into charged fragments Detected by the different charges |
