Mass Spectrometry: Principles and Applications for Chemistry Students

Question 1

In mass spectrometry, which ion type is primarily used to determine the molecular weight of a compound?

Accepted Answer

Protonated molecule

Answer

Radical cation

Answer

Fragment ion

Question 2

In proteomics, how does mass spectrometry contribute to biological research?

Accepted Answer

Mass spectrometry enables the identification and quantification of proteins in complex biological samples.

Answer

Mass spectrometry is limited to determining the molecular weight of proteins.

Answer

Mass spectrometry has no relevance in biological research.

Question 3

What is the primary distinction between positive and negative ion modes in mass spectrometry?

Accepted Answer

Positive ion mode analyzes positively charged ions, while negative ion mode analyzes negatively charged ions.

Answer

Positive ion mode analyzes negatively charged ions, while negative ion mode analyzes positively charged ions.

Answer

Positive ion mode exhibits greater sensitivity than negative ion mode.

Answer

Negative ion mode offers greater versatility than positive ion mode.

Question 4

Which of the following is a potential drawback of using mass spectrometry in chemical analysis?

Accepted Answer

Requires specialized equipment and expertise

Answer

High sensitivity and specificity

Answer

Ability to determine molecular weight and structure

Answer

Non-destructive nature

Question 5

Define a molecular ion.

Accepted Answer

An ion formed by the loss of one or more electrons from a molecule.

Answer

An ion formed by the addition of one or more protons to a molecule.

Answer

An ion formed by the addition of one or more neutrons to a molecule.

Answer

An ion formed by the addition of one or more electrons to a molecule.

Question 6

State the primary purpose of a mass spectrometer.

Accepted Answer

To determine the molecular weight and structure of molecules.

Answer

To separate and identify different elements in a sample.

Answer

To measure the concentration of a particular molecule in a sample.

Answer

To determine the acidity or alkalinity of a solution.

Question 7

Which of the following is not a fragmentation technique used in mass spectrometry?

Accepted Answer

Thin-layer chromatography

Answer

Electron impact

Answer

Chemical ionization

Answer

Electrospray ionization

Question 8

Identify the base peak in a mass spectrum.

Accepted Answer

The peak with the highest intensity

Answer

The peak with the lowest intensity

Answer

The peak corresponding to the molecular ion

Answer

The peak corresponding to the fragment ion

Question 9

What is the primary function of the ion source in a mass spectrometer?

Accepted Answer

To ionize the sample molecules

Answer

To separate the ions by mass-to-charge ratio

Answer

To detect the ions

Answer

To amplify the signal

Question 10

What is the primary function of a quadrupole mass analyzer?

Accepted Answer

To separate ions based on their mass-to-charge ratio

Answer

To detect and amplify ions

Answer

To ionize molecules

Answer

To prepare samples for analysis

Question 11

Which type of mass spectrometry is most suitable for analyzing complex mixtures of compounds, such as those found in biological samples?

Accepted Answer

Liquid chromatography-mass spectrometry

Answer

Gas chromatography-mass spectrometry

Answer

Tandem mass spectrometry

Answer

Time-of-flight mass spectrometry

Question 12

What is the fundamental principle behind tandem mass spectrometry?

Accepted Answer

Fragmenting ions and analyzing them again to gain structural information

Answer

Detecting ions at two different stages to enhance sensitivity

Answer

Separating ions based on their size and charge

Answer

Ionizing ions twice to increase their charge

Question 13

Which fundamental part enables the production of ions in a mass spectrometer?

Accepted Answer

Ion source

Answer

Detector

Answer

Mass analyzer

Answer

Vacuum pump

Question 14

Which ionization technique introduces ions into the gas phase by applying a high voltage to the sample?

Accepted Answer

Electron impact

Answer

Electrospray ionization

Answer

Chemical ionization

Answer

Matrix-assisted laser desorption ionization

Question 15

Which component of a mass spectrometer separates ions based on their mass-to-charge ratio?

Accepted Answer

Mass analyzer

Answer

Detector

Answer

Vacuum pump

Answer

Data system

Question 16

What is the purpose of a collision cell in tandem mass spectrometry?

Accepted Answer

To fragment ions for structural analysis

Answer

To increase the sensitivity of the detector

Answer

To separate ions by their charge

Answer

To calibrate the mass spectrometer

Question 17

Which mode of mass spectrometry operation provides information about the structure and composition of an unknown compound?

Accepted Answer

Tandem mass spectrometry

Answer

Full scan

Answer

Selected ion monitoring

Answer

Isotope ratio monitoring

Question 18

Which of the following is NOT a common application of mass spectrometry?

Accepted Answer

Prediction of weather patterns

Answer

Identification of drugs in biological samples

Answer

Determination of the molecular weight of proteins

Answer

Analysis of environmental pollutants

Question 19

What is the key advantage of using soft ionization techniques in mass spectrometry?

Accepted Answer

Produces less fragmentation

Answer

Enhances sensitivity

Answer

Improves resolution

Answer

Allows for isotopic analysis

Question 20

What is the fundamental difference between a time-of-flight (TOF) and a quadrupole mass analyzer?

Accepted Answer

TOF analyzers measure the time ions take to reach the detector, while quadrupole analyzers measure their mass-to-charge ratio.

Answer

Quadrupole analyzers are more accurate than TOF analyzers.

Answer

TOF analyzers are better suited for analyzing small molecules, while quadrupole analyzers are better for large molecules.

Answer

Quadrupole analyzers are more versatile than TOF analyzers.

Question 21

Which of the following is NOT a critical component of a mass spectrometer, and thus does not play a role in its operation?

Accepted Answer

Incubator

Answer

Ion source

Answer

Mass analyzer

Answer

Detector

Question 22

What is the primary purpose of the ionization process in mass spectrometry?

Accepted Answer

To convert neutral molecules into charged ions, allowing for their analysis based on their mass-to-charge ratio

Answer

To separate ions based on their mass-to-charge ratio

Answer

To detect the presence of ions

Answer

To amplify the signal of the ions

Question 23

Which type of mass analyzer is typically employed for high-resolution analysis, providing more precise and detailed information about the mass-to-charge ratio of ions?

Accepted Answer

Magnetic sector mass analyzer

Answer

Quadrupole mass analyzer

Answer

Time-of-flight mass analyzer

Answer

Ion trap mass analyzer

Question 24

Which of the following ions is a radical ion, characterized by the presence of an unpaired electron?

Accepted Answer

[C6H5]+.

Answer

[C6H5]+

Answer

[C6H5]-

Answer

[C6H5]-.

Question 25

What is a key advantage of using a soft ionization technique in mass spectrometry?

Accepted Answer

Preserves molecular ions, providing more information about the intact molecule

Answer

Produces more fragment ions, enhancing structural elucidation

Answer

Increases sensitivity, improving the detection limits

Answer

Improves resolution, allowing for better separation of ions

Question 26

Which of the following factors does NOT affect the sensitivity of a mass spectrometer, limiting its ability to detect and quantify analytes?

Accepted Answer

Volume of the sample injected

Answer

Ionization efficiency, which influences the number of ions produced

Answer

Abundance of the analyte in the sample

Answer

Mass-to-charge ratio of the analyte, affecting its transmission and detection

Question 27

In a GC-MS system, what is the primary function of the mass spectrometer?

Accepted Answer

Detects and identifies compounds based on their mass-to-charge ratio, providing structural information

Answer

Separates compounds based on their boiling points, enabling their identification

Answer

Provides a visual representation of the separated compounds, aiding in their qualitative analysis

Answer

Quantifies the abundance of the separated compounds, determining their concentrations

Question 28

Which ionization method commonly employed in mass spectrometry generates ions by removing an electron from the analyte molecule?

Accepted Answer

Electron ionization

Answer

Protonation

Answer

Neutral loss

Answer

Fragmentation

Question 29

In a mass spectrum, what does the m/z value represent?

Accepted Answer

The mass-to-charge ratio of the ion

Answer

The molecular weight of the compound

Answer

The abundance of the ion

Answer

The ionization energy of the compound

Question 30

Which type of mass analyzer separates ions based on their time taken to traverse a known distance?

Accepted Answer

Time-of-flight mass analyzer

Answer

Quadrupole mass analyzer

Answer

Ion trap

Answer

Magnetic sector mass analyzer

Question 31

What is the primary purpose of the fragmentation step in mass spectrometry?

Accepted Answer

To elucidate the structure of the compound

Answer

To determine the molecular weight of the compound

Answer

To increase the abundance of the parent ion

Answer

To remove impurities from the sample

Question 32

Which of the following is not a common application of mass spectrometry?

Accepted Answer

Climate modeling

Answer

Drug testing

Answer

Forensic analysis

Answer

Protein sequencing

Question 33

In a mass spectrum, what is the base peak?

Accepted Answer

The ion with the highest abundance

Answer

The ion with the lowest mass-to-charge ratio

Answer

The ion with the molecular weight of the compound

Answer

The ion that is used to calibrate the mass spectrometer

Question 34

How does a molecular ion differ from a fragment ion?

Accepted Answer

A molecular ion retains all the atoms of the original molecule, whereas a fragment ion does not

Answer

A fragment ion is larger than a molecular ion

Answer

A molecular ion is positively charged, while a fragment ion is negatively charged

Answer

There is no distinction between a molecular ion and a fragment ion

Question 35

Which isotope of an element is generally the most abundant in nature?

Accepted Answer

12C

Answer

13C

Answer

14C

Answer

15N

Question 36

In a mass spectrometer, which component is responsible for generating ions from the sample?

Accepted Answer

Ion source

Answer

Mass analyzer

Answer

Detector

Answer

Vacuum pump

Question 37

Which of the following techniques ionizes molecules by bombarding them with high-energy electrons?

Accepted Answer

Electron impact ionization

Answer

Electrospray ionization

Answer

Chemical ionization

Answer

Matrix-assisted laser desorption ionization

Question 38

What is the principle behind time-of-flight mass analyzers?

Accepted Answer

Ions with different mass-to-charge ratios are separated by their velocity.

Answer

Ions with different mass-to-charge ratios are separated by their trajectory.

Answer

Ions with different mass-to-charge ratios are separated by their resonance frequency.

Answer

Ions with different mass-to-charge ratios are separated by their stability in a magnetic field.

Question 39

To determine the molecular weight of an unknown compound using mass spectrometry, which type of ion peak should be considered?

Accepted Answer

Molecular ion peak

Answer

Base peak

Answer

Fragment ion peak

Answer

Isotope peak

Question 40

In mass spectrometry, what factor has no influence on the mass-to-charge ratio of an ion?

Accepted Answer

Velocity

Answer

Isotopic composition

Answer

Charge

Answer

Mass

Question 41

Which type of mass spectrometry technique involves multiple stages of mass analysis?

Accepted Answer

Triple quadrupole mass spectrometry

Answer

Magnetic sector mass spectrometry

Answer

Time-of-flight mass spectrometry

Answer

Fourier transform mass spectrometry

Question 42

Which of the following is the primary purpose of a mass spectrometer?

Accepted Answer

To separate and analyze ions based on their mass-to-charge ratio

Answer

To measure the concentration of a substance in a sample

Answer

To determine the structure of a molecule

Answer

To synthesize new compounds

Question 43

What is the role of the ion source in a mass spectrometer?

Accepted Answer

To generate ions from the sample

Answer

To separate ions by their mass-to-charge ratio

Answer

To amplify the signal produced by the ions

Answer

To detect and record the ions

Question 44

What is the fundamental difference between a positive ion and a negative ion?

Accepted Answer

Positive ions have more protons than electrons, while negative ions have fewer protons than electrons

Answer

Positive ions have fewer protons than electrons, while negative ions have more protons than electrons

Answer

Positive ions have a higher mass-to-charge ratio than negative ions

Answer

There is no difference between positive and negative ions

Question 45

What is the role of a fragmentation pattern in mass spectrometry?

Accepted Answer

To help deduce the molecular structure of the analyte

Answer

To increase the sensitivity of the mass spectrometer

Answer

To simplify the mass spectrum

Answer

To calibrate the mass spectrometer

Question 46

Which of the following accurately describes the primary principle behind mass spectrometry?

Accepted Answer

The process separates molecules based on their charge-to-mass ratio.

Answer

The method separates molecules based on their relative size.

Answer

The technique separates molecules based on their relative solubility.

Answer

The analysis separates molecules based on their different boiling points.

Question 47

Which of the given advantages is NOT associated with a double-focusing mass spectrometer?

Accepted Answer

Faster analysis time

Answer

Enhanced mass accuracy

Answer

Elevated resolving power

Answer

Improved sensitivity

Question 48

Within a mass spectrometer, what is the primary function of the mass analyzer?

Accepted Answer

To separate ions based on their mass-to-charge ratio

Answer

To generate ions

Answer

To detect ions

Answer

To amplify the ion signal

Question 49

Which specific application of mass spectrometry is primarily used to elucidate protein structures?

Accepted Answer

Peptide sequencing

Answer

Metabolite profiling

Answer

Drug discovery

Answer

Environmental analysis

Question 50

What is the underlying principle of operation for a time-of-flight mass spectrometer?

Accepted Answer

Ions are separated based on their mass-to-charge ratio and their time of flight through a known distance.

Answer

Ions are separated based on their velocity through a magnetic field.

Answer

Ions are separated based on their molecular weight.

Answer

Ions are separated based on their charge.

Question 51

What is the primary purpose of a quadrupole mass spectrometer?

Accepted Answer

To separate ions based on their mass-to-charge ratio.

Answer

To detect the presence of specific ions.

Answer

To determine the molecular weight of a compound.

Answer

To identify the structure of a compound.

Question 52

What is the main purpose of using a collision-induced dissociation (CID) cell in mass spectrometry?

Accepted Answer

To fragment ions to obtain structural information.

Answer

To increase the sensitivity of the mass spectrometer.

Answer

To separate ions based on their size.

Answer

To detect the presence of specific elements.

Question 53

Which of the following is a significant limitation of mass spectrometry?

Accepted Answer

It cannot identify the absolute configuration of chiral compounds.

Answer

It cannot determine the elemental composition of compounds.

Answer

It cannot be used to analyze large molecules.

Answer

It cannot be used to determine the molecular weight of compounds.

Question 54

What is the approximate mass range commonly covered by a quadrupole mass spectrometer?

Accepted Answer

m/z 200-2000

Answer

m/z 0-200

Answer

m/z 2000-20000

Answer

m/z 20000-200000

Question 55

Which component is NOT found in a mass spectrometer?

Accepted Answer

Nuclear reactor

Answer

Ion source

Answer

Mass analyzer

Answer

Detector

Question 56

What is the primary purpose of the ion source in a mass spectrometer?

Accepted Answer

To ionize molecules

Answer

To separate ions by mass

Answer

To detect ions

Answer

To amplify the signal from the detector

Question 57

What does the m/z ratio represent?

Accepted Answer

The ratio of the mass of an ion to its charge

Answer

The ratio of the charge of an ion to its mass

Answer

The ratio of the abundance of an ion to its mass

Answer

The ratio of the mass of an ion to its abundance

Question 58

Distinguish between a positive and negative ion.

Accepted Answer

A positive ion has a positive charge, while a negative ion has a negative charge

Answer

A positive ion has a negative charge, while a negative ion has a positive charge

Answer

Positive ions are formed when electrons are lost, while negative ions are formed when electrons are gained

Answer

Negative ions are formed when electrons are lost, while positive ions are formed when electrons are gained

Question 59

What is the primary function of the ionization process in mass spectrometry?

Accepted Answer

To generate charged ions from neutral molecules

Answer

To separate ions based on their mass-to-charge ratio

Answer

To detect the presence of specific ions

Answer

To amplify the signal of ions

Question 60

Which type of mass analyzer separates ions based on their time of flight?

Accepted Answer

Time-of-flight mass analyzer

Answer

Quadrupole mass analyzer

Answer

Ion trap mass analyzer

Answer

Fourier transform ion cyclotron resonance mass analyzer

Question 61

What is the underlying principle of electrospray ionization (ESI) in mass spectrometry?

Accepted Answer

It generates multiply charged ions of the analyte

Answer

It is specifically suitable for small organic molecules

Answer

It enables the analysis of volatile compounds

Answer

It is a hard ionization technique

Question 62

In mass spectrometry, the term 'base peak' refers to:

Accepted Answer

The peak with the highest abundance

Answer

The peak with the lowest abundance

Answer

The peak with the highest mass-to-charge ratio

Answer

The peak with the lowest mass-to-charge ratio

Question 63

What is the primary function of the ion source in mass spectrometry?

Accepted Answer

To ionize the sample molecules

Answer

To introduce the sample into the mass spectrometer

Answer

To separate the ions based on their mass

Answer

To detect the ions

Question 64

In mass spectrometry, what is the term for the peak with the highest intensity in a mass spectrum?

Accepted Answer

Base peak

Answer

Parent ion peak

Answer

Molecular ion peak

Answer

Fragment ion peak