Instrumental Analysis Midterm questions with
verified answers
_____ are the most widely used separation techniques used by
scientists Ans✓✓✓ chromatographic methods
_____ is the main theme in polarity-based chromatography Ans✓✓✓
like attracts like
1 eV = ____ Ans✓✓✓ 1.602x10^-19 J
a compound that has no affinity to the stationary phase will move with
the mobile phase and the time taken for elution of an unretained
sample component is called the ____ Ans✓✓✓ 'void' or 'dead time'
time (t0) of the column
a retained component spends time in the stationary and mobile phases
and the net time the component spends in the mobile phase is called
the ____ Ans✓✓✓ net retention time (tr)
a solute's retention time or retention volume in chromatography is
directly related to the ____ Ans✓✓✓ strength of the solute's
interaction with the mobile and stationary phases
A term in VDM Equation Ans✓✓✓ eddy diffusion
,A variety of methods are used to create ions in MS, ____ Ans✓✓✓
mostly positive ions
AC media have ligands that are ____ Ans✓✓✓ bonded via a spacer
arm to the packing material
Acetonitrile is less viscous than methanol, thus causing ____ Ans✓✓✓
less fluctuations in pressure and less bubble formation occurs when it is
mixed with water
acetonitrile is the reverse phase solvent of choice because the UV cut
off for acetonitrile is 190 n, allowing ____ Ans✓✓✓ detection at lower
wavelengths
Adsorption Chromatography Ans✓✓✓ Chromatography in which
separation is based mainly on differences between the adsorption
affinities of the sample components for the surface of an active solid
stationary phase.
Affinity Chromatography (AC) is based on the ____ Ans✓✓✓ specific
adsorption of a molecule to a ligand or macromolecule
, Affinity Chromatography Ans✓✓✓ the particular variant of
chromatography in which the unique biological specificity of the
analyte and ligand interaction is utilized for the separation
all ion-pairing agents are potentially capable of ion-pairing with the
positively charged basic residues of peptides or proteins, thus ____
Ans✓✓✓ reducing hydrophilicity and increasing their retention times
All odd-electron ions have even m/z values unless ____ Ans✓✓✓ they
contain an odd number of nitrogen
All of these techniques are typically done on stationary phases that
have been ____ Ans✓✓✓ synthesized with a pore-size distribution
over a range that permits the analysis of interest to enter, or to be
excluded from, more or less of the pore volume of the packing
All these collisions will ____ (the resulting spectrum will be extremely
hard to interpret) Ans✓✓✓ increase the complexity of the ions
produced and hence the spectrum
All these various fragmentation pathways give rise to the _____
Ans✓✓✓ mass spectrum of the compound
almost all biological molecules can be purified on the basis of ____
Ans✓✓✓ specific interaction between their chemical structure and a
suitable affinity ligand
verified answers
_____ are the most widely used separation techniques used by
scientists Ans✓✓✓ chromatographic methods
_____ is the main theme in polarity-based chromatography Ans✓✓✓
like attracts like
1 eV = ____ Ans✓✓✓ 1.602x10^-19 J
a compound that has no affinity to the stationary phase will move with
the mobile phase and the time taken for elution of an unretained
sample component is called the ____ Ans✓✓✓ 'void' or 'dead time'
time (t0) of the column
a retained component spends time in the stationary and mobile phases
and the net time the component spends in the mobile phase is called
the ____ Ans✓✓✓ net retention time (tr)
a solute's retention time or retention volume in chromatography is
directly related to the ____ Ans✓✓✓ strength of the solute's
interaction with the mobile and stationary phases
A term in VDM Equation Ans✓✓✓ eddy diffusion
,A variety of methods are used to create ions in MS, ____ Ans✓✓✓
mostly positive ions
AC media have ligands that are ____ Ans✓✓✓ bonded via a spacer
arm to the packing material
Acetonitrile is less viscous than methanol, thus causing ____ Ans✓✓✓
less fluctuations in pressure and less bubble formation occurs when it is
mixed with water
acetonitrile is the reverse phase solvent of choice because the UV cut
off for acetonitrile is 190 n, allowing ____ Ans✓✓✓ detection at lower
wavelengths
Adsorption Chromatography Ans✓✓✓ Chromatography in which
separation is based mainly on differences between the adsorption
affinities of the sample components for the surface of an active solid
stationary phase.
Affinity Chromatography (AC) is based on the ____ Ans✓✓✓ specific
adsorption of a molecule to a ligand or macromolecule
, Affinity Chromatography Ans✓✓✓ the particular variant of
chromatography in which the unique biological specificity of the
analyte and ligand interaction is utilized for the separation
all ion-pairing agents are potentially capable of ion-pairing with the
positively charged basic residues of peptides or proteins, thus ____
Ans✓✓✓ reducing hydrophilicity and increasing their retention times
All odd-electron ions have even m/z values unless ____ Ans✓✓✓ they
contain an odd number of nitrogen
All of these techniques are typically done on stationary phases that
have been ____ Ans✓✓✓ synthesized with a pore-size distribution
over a range that permits the analysis of interest to enter, or to be
excluded from, more or less of the pore volume of the packing
All these collisions will ____ (the resulting spectrum will be extremely
hard to interpret) Ans✓✓✓ increase the complexity of the ions
produced and hence the spectrum
All these various fragmentation pathways give rise to the _____
Ans✓✓✓ mass spectrum of the compound
almost all biological molecules can be purified on the basis of ____
Ans✓✓✓ specific interaction between their chemical structure and a
suitable affinity ligand
