CD7+8 - Fats + GLC Flashcards
difference between fats + oils
at room temp:
fats = solid
oils = liquid
why do fats/oils not mix with water
long, non-polar FATTY ACID chain
carboxylic acids in fats + oils
- even no. C atoms (up to 24)
- usually unbranced hydrocarbon chains
how can an oil/fat be identified?
HYDROLYSIS
break down into glycerol + fatty acid - measure amount of each acid present
heat with conc. NaOH = glycerol + sodium salts of fatty acids
how can the fatty acids be released from the sodium salts
+ dilute mineral acid e.g. HCl
mobile phase in GLC
unreactive gas = “carrier gas”
e.g. nitrogen
stationary phase in GLC
small amount liquid with high BP
held on a finely divided inert porous solid support
the complete apparatus used to carry out the GLC is called
gas-liquid chromatograph
How do the different components separate?
- each component = diff. affinity for stationary vs. mobile phase
- components have diff. solubilities in the liquid stat. phases
- some dissolve in stat. + some remain in gaseous mob. phase
- each component distributes itself to diff extents between 2 phases
- = emerges column at diff. times
compounds that favour the mobile phase are…
carried QUICKER
what does Kpc stand for?
partition coefficient
what is the equation for Kpc?
component in STATIONARY phase / component in MOBILE phase
results from GLC shown are shown as a….
chromatogram
How are the products detected in GLC?
- chromatogram
- each component = peak
- larger instruments = pure sampe of each compound collected as it emergers
- adanced instruments = connected to mass spectrometer - identified directly
what is retention time?
time a compound is held in a column
under given conditions
= characteristic of the compound
