Separations and Purifications Flashcards
adsorption: how well a component of the mixture ____ to the ____ phase
sticks, stationary
solubility: how well a component of the mixture ____ in the ____ phase
dissolves, mobile
the higher the adsorption to the stationary phase, the ___ the molecule will move through the column
slower
the higher the solubility in the mobile phase, the ____ the molecule will move through the column
faster
The ____ of a component is the distance travelled by the component over the distances traveled by the solvent (mobile phase)
retention factor
thin layer chromatography: stationary phase = _____, mobile phase = _______; non-polar compounds are ____ (___Rf) while polar-compounds are _____ (___ Rf).
stationary phase = glass plate coated in absorbent material (silica or alumina)
Mobile phase = organic solvent
non polar = more soluble (higher Rf)
polar = more adsorbent (lower Rf)
Column chromatography: silica acts as the ____ and the _____ (mobile phase) is then allowed to flow through the silica beads; the different components of the analyte exhibit varying degrees of ___ to the silica = travel at different speeds through ____ as the solvent flows through it
stationary phase, solvent, adhesion, the stationary phase
Column chromatography: The components that adhere more strongly to the stationary phase travel ____ compared to those with a weaker adhesion
slower
High-pressure liquid chromatography (HPLC): a more accurate version of column chromatography; HPLC uses a ___ to force the solvent through the column at high pressure; particularly useful for mixtures containing ____ which have a ____ resistance to the mobile phase flow.
pump, very small particles, higher
Gas chromatography involves samples being ____ and passed through a liquid or solid ___ phase using a gaseous (nitrogen or argon) ____ phase; the molecules with the ____ BP come out of the column first; at the end of the stationary phase, there is a detector that works out ____ are found at different times.
vaporized, stationary, mobile, lowest, how many particles of each component
Distillation is a purification method where the components of a liquid mixture are ___ and then ___ and ___ at different boiling point
vaporized, condensed, isolated
Distillation is an effective method to separate mixtures comprised of _____
2 or more pure liquids
In simple distillation, a mixture is heated and the most volatile component vaporizes (evaporates) ___, at the _____ temperature. The vapor passes through a cooled tube, where it condenses back into liquid state –> pure, condensed liquid that is collected is called the ____.
first, lowest, distillate
Fractional Distillation is used when there is a more complex mixture often with many fractions with not just fixed ____ but ___ of temperature where they boil
boiling points, ranges
Vacuum distillation uses a vacuum to ____ the boiling point of the components so lower temperatures can be used for more ____ substances
lower, volatile
A phenomenon in which increased surface tension allows a liquid to exceed its boiling point without actually boiling
superheating
If the tension is broken during superheating, ____ can occur. To prevent this, ___ are often added as a nucleation surface to encourage the formation of air bubbles during boiling.
violent flash boiling, boiling chips
The aqueous phase contains _____
water and other charged ions and species
the organic phase contains ____
neutral compounds in the organic solvent
In oil and water mixture (immiscible liquids), the aqueous phase forms at the bottom because ____, and the oil layer form on the top since it has ____
water is denser, a lower density
The more dense, top layer is often the ____
organic layer
Extraction with a separating funnel is useful to separate reaction product mixtures where the desired product and the side products have ____
different solubilities
Extraction is not an effective method to separate _____ because most are miscible with each other
two organic layers
A racemic mixture is a _____ of _______
50:50 mixture of two enantiomers
In a racemic mixture, each enantiomer rotates plane-polarized light in an equal but opposite direction (because they are ___ images) so the racemic mixture is optically ____.
mirror, inactive
One method for resolving a racemic mixture is the reaction of that racemate with an enantiomerically-pure ___ –> produces a mixture of ____
chiral reagent, diastereomers
enantiomers have ____ physical properties = makes them ___ to separate; diastereomers have ___ physical properties = __ to separate
identical, hard, different, easy
___ can also be used to separate a racemic mixture, a ___ stationary phase that will only bind to the __ is used to isolate one of the confirmations
chromatography, chiral, R of S confirmation
proteins in their natural, tertiary-structured states can be run on ____ gels, which separates proteins by both ____ and ____.
native-PAGE, size and conformation
Proteins can be chemically denatured before running them on the gel = _____, in this case proteins are separated exclusively by ____.
SDS-Page, size
Proteins can be further denatured by the addition of a reducing agent that breaks down the ____ bonds between ___ residues, these are not fully broken by SDS alone
disulfide, cysteine,
Samples of proteins and peptides can also be separated by _____ chromatography, in which molecules in solution are separated by their _____
size-exclusion, molecular weight
Size-exclusion chromatography: as the solution travels down the column some ___ particles get stuck in the pores, the ___ molecules simply pass by the pores because ___. ___ molecules flow through the column ____ than ____ molecules, so ____ molecules have longer retention times
small, large, they are too larger to enter the pores, larger, faster, smaller, smaller
ion exchange chromatography is used to separate molecules (or proteins) according to their ___.
charge
Ion exchange chromatography is based on the _____ between ___ charged ions
attraction, oppositely
A cationic stationary phase is used to separate ____ in cation-exchange chromatography
ANIONS
An anionic stationary phase is used to separate ___ in anion exchange chromatography
CATIONS
Affinity purification of protein complexes involves a specific protein being manipulated to express an ___ tag. The tag serves as a tool to ___ the bait protein and associated proteins by ____ chromatography. This occurs when the ____ on the protein is attracted to a _____ antigen/nucleic acid in the chromatography process.
affinity, purify, affinity, affinity tag, highly specific
Is used to identify and determine the composition of a molecule, an energy source causes the molecule to break into smaller fragments which are detected by their ___ ratio
Mass spectrometry, mass to charge ratio
enables scientists to determine the 3-D structure of a protein crystal at atomic resolution by analyzing the patterns created by deflected X-rays
x-ray crystallography
uses the magnetic properties of atoms to determine the composition and 3-D structure of proteins in solution.
Nuclear magnetic resonance (NMR)
