60 Questions
Which technique offers the highest resolution of up to 10 million?
FT-ICR
Which ionization method involves proton/electron transfer from a solid mixed with matrix?
MALDI
Which technique is best suited for volatile thermally-stable compounds?
EI
Which method uses photoionization of reagent gas to induce analyte ionization?
APPI
Which technique forms charged droplets that undergo coulombic fission?
ESI
Which method uses RF and DC voltages to selectively transmit ions of a given m/z?
Quadrupole
How does atmospheric pressure photoionization (APPI) differ from electrospray ionization (ESI) in terms of the type of analytes best suited for analysis?
APPI is better for non-polar compounds, while ESI is better for polar compounds.
In the ionization process of APPI, why is a reagent gas like toluene or acetone used?
To transfer energy to produce ions from the analyte molecules.
What reactions lead to the ionization of molecules in APPI?
R* + M → R+ + M + e-
How does electrospray ionization (ESI) produce multiple charged ions from analyte molecules?
Through solvent evaporation and coulombic fission.
What is the significance of multiple charging in mass spectrometry?
It facilitates dissociation during tandem MS experiments.
How do highly charged droplets in ESI achieve multiple charging of analyte molecules?
By concentrating the charge on the analyte molecules as droplets shrink in size.
What is the key advantage of matrix-assisted laser desorption ionization (MALDI) over other ionization techniques?
Ability to analyze non-volatile biomolecules
What factor plays a crucial role in determining the resolution of a mass spectrometer?
Ion kinetic energy spread
In electrospray ionization, which type of analyte generally ionizes most effectively?
Polar, charged molecules
What is a key limitation of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers?
High cost and complexity
How does time-of-flight (TOF) mass analyzer achieve high resolution?
By measuring ions' flight times down a field-free drift tube
Which factor influences the ionization efficiency of an analyte in electrospray ionization?
$pKa$ of the analyte
What makes ion mobility spectrometry (IMS) valuable when coupled with mass spectrometry?
It provides additional structural information about ions
In MALDI, what role does the matrix play in the ionization process?
$UV$- absorbing matrix transfers protons to the analyte molecules
How does a quadrupole mass analyzer selectively transmit ions based on their m/z?
By applying both RF and DC voltages to the four parallel rods
What is a key advantage of ion trap mass analyzers compared to quadrupole mass analyzers?
High trapping efficiencies
How does time-of-flight mass spectrometry achieve high resolving power?
By separating ions based on their time-of-flight in a drift tube
In ultraviolet photodissociation (UVPD), how do ions undergo dissociation?
By direct bond cleavages from absorption of UV photons
What does Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) use to trap ions?
Magnetic field
How does ion mobility spectrometry (IMS) separate ions?
Based on their drift times in a buffer gas
What differentiates infrared multiphoton dissociation (IRMPD) from collision-induced dissociation (CID) in terms of fragmentation?
IRMPD uses direct bond cleavages
What role does mass defect play in determining molecular formulas from high-resolution mass spectra?
It helps determine possible molecular formulas by considering isotopic patterns
In multiple reaction monitoring (MRM) mode, what does the first quadrupole do in a triple quadrupole mass spectrometer?
Isolates a precursor ion
How does atmospheric pressure photoionization (APPI) differ from electrospray ionization (ESI) in terms of the ionization process?
APPI ionizes reagent gas molecules, while ESI ionizes analyte molecules in solution.
What is the significance of multiple charging in electrospray ionization (ESI) mass spectrometry?
Highly charged ions are more readily fragmented in tandem MS experiments.
Which type of analytes are better suited for analysis by electrospray ionization (ESI) compared to atmospheric pressure photoionization (APPI)?
Polar compounds
Why do highly charged droplets in electrospray ionization (ESI) achieve multiple charging of analyte molecules?
Due to solvent evaporation and coulombic fission
What role does the reagent gas play in the ionization process of atmospheric pressure photoionization (APPI)?
It helps transfer energy to produce ions from the analytes.
What type of analytes are best suited for analysis by atmospheric pressure photoionization (APPI) compared to electrospray ionization (ESI)?
Non-polar compounds that are difficult to ionize
Which mass spectrometry technique involves electron bombardment for ionization causing fragmentation?
EI
Which mass spectrometry technique forms charged droplets that undergo coulombic fission?
ESI
What type of compounds are Electron Impact (EI) ionization best suited for?
Volatile thermally-stable compounds
Which mass spectrometry technique involves proton/electron transfer from a solid mixed with matrix?
MALDI
Which method uses photoionization of reagent gas to induce analyte ionization?
APPI
What differentiates Quadrupole mass analyzers from Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass analyzers?
Simple design
What additional information does ion mobility spectrometry (IMS) provide compared to conventional mass spectrometry?
Drift time in a buffer gas
How does ultraviolet photodissociation (UVPD) differ from collision-induced dissociation (CID) in terms of energy absorption for fragmentation?
UVPD uses lower energy photons than CID.
What is the main advantage of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) over other techniques?
Extremely high resolution mass spectra
How does quadrupole mass analyzer achieve selective transmission of ions based on their m/z?
By scanning RF/DC voltage and amplitude
What type of bond cleavages are induced by infrared multiphoton dissociation (IRMPD) compared to collision-induced dissociation (CID)?
Peptide backbone cleavages
What role does time-of-flight (TOF) play in achieving high resolving power in mass spectrometry?
Separating ions based on drift time
What distinguishes ion trap mass analyzers from quadrupole mass analyzers in terms of mass range capabilities?
Quadrupole analyzers have a limited mass range.
How does multiple reaction monitoring (MRM) mode differ from other modes in triple quadrupole mass spectrometers?
MRM isolates and fragments ions sequentially.
What is the key strength of ion trap mass analyzers compared to quadrupole mass analyzers?
High trapping efficiency and multi-stage MS/MS capabilities
What is a key advantage of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers over other mass analyzers?
Highest resolution and most accurate mass measurements
Which factor plays a crucial role in determining the mass resolution of a mass spectrometer?
Ion kinetic energy spread
In ion mobility spectrometry coupled with mass spectrometry, ions are separated based on what characteristic?
Drift time in buffer gas
What is the main limitation of matrix-assisted laser desorption ionization (MALDI) as a mass spectrometry technique?
Limited mass range
How do quadrupole mass filters function in mass analysis?
By selectively transmitting ions based on their m/z through a hyperbolic field
What is a key strength of time-of-flight (TOF) mass analyzers compared to other mass analyzers?
High resolution and high duty cycle
Which factor does NOT typically influence the ionization efficiency of an analyte in electrospray ionization?
$m/z$ ratio of the analyte
What separates ions based on their time of flight down a field-free drift tube?
Time-of-flight (TOF) analyzer
What type of ions does matrix-assisted laser desorption ionization (MALDI) predominantly form from solid samples?
[M+H]+ ions
In Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers, how are ions trapped before analysis?
Electrostatically between an inner spindle and outer barrel
Learn about the ionization and fragmentation processes that occur during Electron Ionization (EI), which uses a 70eV electron beam to ionize samples causing extensive fragmentation. Understand how incident electrons eject outer shell electrons, leaving the sample with a net positive charge.
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