analytical techniques Flashcards
chromatography
separates the components of an organic mixture
components absorb (stationary) & desorb (mobile) at different rates
dependent on the solubility of the solvents
mobile phase
solvent moving up the filter paper
component desorbed
stationary phase
solvent adsorbed to the filter paper
component adsorbed
solvent front
(Rᶠ value)
distance travelled by the solvent up the filter paper
(component front ÷ solvent front)
paper chromatography
polar mobile phase (e.g. H₂O)
polar components move up the filter paper faster
thin-layer chromatography
polar stationary phase (e.g. Al₂O₃)
polar components move up the filter paper slower
high-performance liquid chromatography
solid stationary phase & liquid mobile phase (e.g. methanol)
soluble components exit the column faster
electrophoresis of proteins
sodium dodecyl sulfate denatures proteins (∴ negative charge)
proteins inserted at the negative terminal (cathode)
buffer solution gel (∴ ions conduct electricity)
electrophoresis chamber creates an electric current
smaller proteins migrate toward the positive terminal (anode) faster
(∴ proteins separated by size)
electrophoresis of amino acids
buffer solution gel is a specific pH & amino acids have specific isoelectric points
amino acids placed in the middle of the gel
if pH < pI : zwitterion → cation (∵ abundance of H⁺)
∴ migrates → anode
if pH > pI : zwitterion → anion (∵ abundance of OH⁻)
∴ migrates → cathode
(∴ amino acids separated by charge)
base peak
most abundant ion
(100% relative intensity)
molecular ion peak
heaviest ion
(highest m/z value)
alcohol
infrared spectra
broad O-H @ 3350
amine
infrared spectra
weak N-H @ 3500
aldehyde
infrared spectra
sharp C=O @ 1725
multiple C-H @ 2900
ketone
infrared spectra
sharp C=O @ 1725
single C-H @ 2900
