Mass Spectrometer Quiz with Answers: Test Your Understanding

📚 Quick Study Guide

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• Mass Spectrometry: An analytical technique used to measure the mass-to-charge ratio of ions.
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• Ionization: Molecules are converted into ions, which can be positive or negative. Common methods include Electron Ionization (EI) and Electrospray Ionization (ESI).
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• Acceleration: Ions are accelerated through an electric field. The kinetic energy gained is given by $KE = zV$, where $z$ is the charge and $V$ is the accelerating voltage.
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• Deflection: Ions are deflected by a magnetic field. The radius of curvature $r$ is related to the mass-to-charge ratio ($m/z$) by the equation: $r = \frac{mv}{zB}$, where $m$ is the mass, $v$ is the velocity, and $B$ is the magnetic field strength.
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• Detection: Ions are detected based on their $m/z$ values. The detector measures the abundance of each ion.
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• Mass Spectrum: A plot of ion abundance versus $m/z$. The base peak is the most abundant ion. Molecular ion peak (M+) represents the intact molecule minus one electron.

🧪 Practice Quiz

1. Which of the following is the primary purpose of a mass spectrometer?
   1. Measuring the volume of a gas
   2. Determining the elemental composition of a sample
   3. Separating molecules based on their boiling points
   4. Measuring the mass-to-charge ratio of ions
2. In mass spectrometry, what process typically occurs during ionization?
   1. Molecules are cooled to form crystals
   2. Molecules are converted into ions
   3. Molecules are separated by size
   4. Molecules are dissolved in a solvent
3. What does the base peak in a mass spectrum represent?
   1. The ion with the smallest mass-to-charge ratio
   2. The most abundant ion
   3. The molecular ion
   4. The least abundant ion
4. Which equation relates the radius of curvature ($r$) of an ion's path in a magnetic field to its mass ($m$), velocity ($v$), charge ($z$), and magnetic field strength ($B$)?
   1. $r = \frac{zv}{mB}$
   2. $r = \frac{mv}{zB}$
   3. $r = \frac{mz}{vB}$
   4. $r = \frac{Bz}{mv}$
5. What is the role of the acceleration stage in a mass spectrometer?
   1. To neutralize the charge of ions
   2. To increase the kinetic energy of ions
   3. To separate ions by mass
   4. To reduce the pressure in the instrument
6. What type of plot is generated by a mass spectrometer?
   1. Voltage versus current
   2. Temperature versus pressure
   3. Ion abundance versus mass-to-charge ratio
   4. Velocity versus time
7. Which of the following ionization methods is commonly used for large biomolecules like proteins?
   1. Electron Ionization (EI)
   2. Chemical Ionization (CI)
   3. Electrospray Ionization (ESI)
   4. Field Ionization (FI)