Analysis Work Flashcards
what are different chemical shifts
carbon-13 atoms in different environments
benefits of C-13 NMR
fewer peaks to sort
better separation of peaks
never any coupling
types of chromatography
paper
thin layer
gas
2 phases of chromatography
stationary- paper
mobile- solvent that moves over the paper
how does separation occur
by adsorption at the surface of the stationary phase
how to calculate Rf value
distance substance moved/distance moved by solvent
what is a Rf value
measure of how soluble it is in a particular solvent
what does a greater Rf value mean
the more soluble the substance is in that solvent
what is gas chromatography
a technique used to identify substances present in a complex mixture
what is the mobile and stationary phase of gas chromatography
mobile- inert gas
stationary- high boiling point liquid adsorbed to the surface of a solid material
what is the mobile phase called in gas chromatography
carrier gas
what is the long tube containing the liquid stationary phase called in gas chromatography
column
what is retention time
the time from a sample being injected to each component in the sample leaving the column
limitations of gas chromatography
only works on volatile substances
doesn’t work well for large biological molecules
what pieces of info do you get from gas chromatography
number of substances (peaks) relative abundance (area= base x 0.5height)
