What is the function of a mass spectrometer? The ionization of molecules or atoms The separation of the ion fragments The detection of ions All of these
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A mass spectrometer is an instrument used to separate ions of slightly different masses. Often these are isotopes of an element, and as such, they have very similar chemical properties. The construction of a mass spectrometer is shown in the figure below. Ions of charge +q and mass m are accelerated through a potential difference V0. The ions then move perpendicularly into magnetic field B, where they are bent along a semicircular path. They are detected at a distance d = 2r from the entry port. Determine the ion mass in terms of the known parameters and explain the process.
Rashmi S.
1. Uses a radiofrequency electric field in three dimensions to tune the mass/charge ratio that can reach the detector. Only mass/charge ratios with unstable oscillations will reach the detector. 2. Uses a magnetic field to separate high-velocity ions based on a momentum/charge ratio, with a slit determining which momentum/charge ratio will enter the detector. 3. Uses a radiofrequency electric field in two dimensions to tune the mass/charge ratio that can reach the detector. Only mass/charge ratios with a stable oscillation will reach the detector. One of the best detectors for quantification. 4. Uses a magnetic field to trap low-velocity ions. The speed of the ion as it orbits the trap is detected by a sensor, which can convert the signal to a mass-to-charge ratio. 5. Uses a kind of "molecular race" to measure the time taken from ion formation to detection. Can handle ions of almost any mass/charge ratio. Options: - Time of flight - Sectors - Quadrupole - Quadrupole ion-trap - Fourier transform ion cyclotron resonance
Dominador T.
A Mass Spectrometer It is possible to accelerate ions to a known kinetic energy in an electric field. Sometimes chemists and physicists do this as part of a method to identify the chemical elements present in a beam of ions by determining the mass of each ion. This can be done by bending the ion beam in a uniform magnetic field and measuring the radius of the semicircular path each ion takes. A device that does this is called a mass spectrometer. $\mathrm{A}$ schematic of a mass spectrometer is shown in Fig. $29-40$.
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