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Mass Spectrometry Quiz

Mass Spectrometry Quiz

Test your knowledge on mass spectrometry and its history

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  • 1.
    List these compounds according to their increasing mass: hydrazine (H4N2), oxygen (O2), methanol (CH4O).

    Your answer:
    Correct answer:

    The monoisotopic masses of these compounds are 31.989829 Da (oxygen), 32.026215 Da (methanol), and 32.037448 Da (hydrazine).

  • 2.
    What is the base peak in the mass spectrum?

    Your answer:
    Correct answer:

    The base peak is the peak with the greatest intensity among all peaks in the spectrum. The intensity of each peak in the spectrum is expressed as a percentage relative to the intensity of the base peak.

  • 3.
    Who first reported the fragmentation after the gamma hydrogen rearrangement to an unsaturated group via a sixmembered intermediate?

    Your answer:
    Correct answer:
    It was first reported by Australian A. J. C. Nicholson in 1954 (Trans. Faraday Soc. 50: 1067-1073). The reaction description was published five years later (Anal. Chem. 1959, 31: 82–87) by the American chemist Fred McLafferty, by whose name we now refer to the rearrangement (McLafferty rearrangement).

  • 4.
    Mass spectrometers known as calutrons were used for the industrial separation of uranium isotopes during the Manhattan Project. A large amount of copper was needed to make their magnetic coils. How was the highly-valued metal obtained during the war?

    Your answer:
    Correct answer:

    During the war, copper was preferably used for the production of brass shell casings and it was not available for the construction of calutrons. The designers came up with the idea of replacing copper with silver. They borrowed about 13,300 tons of silver from the West Point Bullion Depository in West Point, NY. After the war, the silver was returned to the Treasury with virtually no loss.

  • 5.
    Who made molecular elephants fly?

    Your answer:
    Correct answer:
    John Fenn was awarded Nobel Prize in Chemistry in 2002 for his work related to electrospray ionization of biological macromolecules. His famous phrase, "we made elephants fly" refers to the ability of electrospray to generate gas-phase ions from big protein molecules.

  • 6.
    How long would be a paper needed for printing a profile mass spectrum measured in the m/z 0 1000 range at a resolution of 50,000 at m/z 500 if the peaks were to be 1 mm wide at their half maximum? Let us consider a constant width of all peaks.

    Your answer:
    Correct answer:

    The resolution can be expressed as (m/z)/Δ(m/z), where Δ (m/z) is the peak width at 50 % of its maximum. For a resolution of 50,000 at m/z 500, the value of Δ(m/z) is 0.01. If the Δ(m/z) is to correspond to 1 mm, then the total width of the spectral record equals 1000/0.01 mm, which is 100,000 mm, which is 100 m.

  • 7.
    The quadrupole mass filter has been known since the mid-1950s thanks to the work of Wolfgang Paul. The motion of ions in a quadrupole field can be described by solving second-order differential equations. When were these equations solved mathematically?

    Your answer:
    Correct answer:

    The solution of differential equations of this type came from the French mathematician Émile Léonard Mathieu (1835-1890), who studied the mechanical vibrations of the elliptical drumheads.

  • 8.
    What is the trajectory of a charged particle moving perpendicularly to a uniform magnetic field in a vacuum?

    Your answer:
    Correct answer:

    The magnetic force is perpendicular to the velocity so that it does no work on the charged particle. The particle’s kinetic energy and speed thus remain constant. The direction of motion is affected but not the speed.

  • 9.
    Chemical ionization (CI) is a soft ionization technique used in mass spectrometry. Who discovered it?

    Your answer:
    Correct answer:

    Chemical ionization was discovered in the laboratories of the Humble Oil and Refining Company in Baytown, TX. Munson and Field’s seminal paper on chemical ionization was published in 1966.  [https://doi.org/10.1021/ja00964a001]

  • 10.
    What is the electric charge of an ion with m/z = m?

    Your answer:
    Correct answer:

    The particle carries one elementary charge, the value of which is 1.602 176 634 × 10−19 C (exactly).

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