Passage
In mass spectrometry, a sample's molecules are ionized in a vacuum and then exposed to a uniform electric field created by a high-voltage plate in the acceleration chamber. The electric field accelerates the ions until they arrive at the next section of the device, designated as the separation chamber. In this section, the drifting ions are sorted by their mass-to-charge ratio (m/q) .The separation chamber in a time-of-flight mass spectrometer (TOF-MS) is linear and has no electric or magnetic fields. The ions travel at a constant velocity through the chamber until they reach the detector. The time it takes for an ion to reach the detector depends on its m/q ratio.
Figure 1 Time-of-flight mass spectrometerA magnetic sector mass spectrometer (MS-MS) has a curved separation chamber where a magnetic field is generated. The magnetic field exerts a centripetal force on drifting ions, bending their trajectories into curved paths. The radius of the curvature depends on the ion's m/q.
Figure 2 Magnetic sector mass spectrometerThe centripetal force (F) acting on a particle can be determined from its mass (m) and velocity (v) and the radius (r) of the curved path:F = mv²/rEquation 1
-Which expression gives the ion's radius of curvature in a magnetic field EM_/_ for an ion with a mass of m, charge of q, and velocity of v?

Question

Passage
In mass spectrometry, a sample's molecules are ionized in a vacuum and then exposed to a uniform electric field created by a high-voltage plate in the acceleration chamber. The electric field accelerates the ions until they arrive at the next section of the device, designated as the separation chamber. In this section, the drifting ions are sorted by their mass-to-charge ratio (m/q) .The separation chamber in a time-of-flight mass spectrometer (TOF-MS) is linear and has no electric or magnetic fields. The ions travel at a constant velocity through the chamber until they reach the detector. The time it takes for an ion to reach the detector depends on its m/q ratio.

Figure 1 Time-of-flight mass spectrometerA magnetic sector mass spectrometer (MS-MS) has a curved separation chamber where a magnetic field is generated. The magnetic field exerts a centripetal force on drifting ions, bending their trajectories into curved paths. The radius of the curvature depends on the ion's m/q.

Figure 2 Magnetic sector mass spectrometerThe centripetal force (F) acting on a particle can be determined from its mass (m) and velocity (v) and the radius (r) of the curved path:F = mv²/rEquation 1
-Which expression gives the ion's radius of curvature in a magnetic field EM_/_ for an ion with a mass of m, charge of q, and velocity of v?

Quizplus · Accepted Answer

11ecba2d_12e2_ca34_a3bf_9d2287aa92a3_MD0008_00 According to the passage, the centripetal force (F) exerted on an ion in MS-MS is related to the ion's mass (m) and velocity (v), and the radius (r) of the curved path (Equation 1): 11ecba2d_12e2_ca35_a3bf_c7e9c1b817ef_MD0008_00 This force is a result of the force exerted on an ion in a magnetic field. This is known as the magnetic Lorentz force, and it is calculated as the product of the ion's charge (q), the ion's velocity (v), and the magnitude of the magnetic field (_EMEM_): 11ecba2d_12e2_ca36_a3bf_cb9798e911d8_MD0008_00 Because the force due to the magnetic field is the only force exerted on the ion, the centripetal force is equal to the Lorentz force: 11ecba2d_12e2_f147_a3bf_5927ba523d22_MD0008_00 This equation is rearranged to solve for the radius of curvature: 11ecba2d_12e2_f148_a3bf_47cef88767c2_MD0008_00 This equation shows that the ion's radius of curvature is directly proportional to its m/q ratio (Choices C and D). In addition, the radius increases with the ion's velocity and decreases with the strength of the magnetic field. Educational objective: The force exerted on a moving particle in a magnetic field is known as the magnetic Lorentz force, and it is equal to the product of the particle's charge, velocity, and strength of the magnetic field: F = qvB. This force is the centripetal force that curves the path of ions in MS-MS. Therefore, an expression for the radius of curvature can be determined by equating the Lorentz force and centripetal force equations.

Passage in Mass Spectrometry, a Sample's Molecules Are Ionized in a a Vacuum