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Mass Spectrometry Quiz

Mass Spectrometry Quiz

Test your knowledge on mass spectrometry and its history

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  • 1.
    What principle of positive ray detection was used in the first Thomson's parabola spectrographs?

    Your answer:
    Correct answer:

    In the spectrographs used by Thomson until 1910, the rays of positive electricity were detected by the phosphorescence they produced on a willemite screen. The screen was made by grinding rare zinc mineral willemite into a fine powder. After shaking in alcohol, the suspension was allowed to deposit slowly on a glass plate. Later, a photographic plate inside the spectrograph was used for more sensitive detection.

  • 2.
    Which element has the largest number of stable isotopes?

    Your answer:
    Correct answer:
    Naturally occurring tin is a mixture of its ten stable isotopes and they are found in the percentages as follows: 112Sn (1.0 %), 114Sn (0.7 %), 115Sn (0.3 %), 116Sn (14.5 %), 117Sn (7.7 %), 118Sn (24.2 %), 119Sn (8.6 %), 120Sn (32.6 %), 122Sn (4.6 %), and 124Sn (5.8 %). Molybdenum has six stable isotopes, ytterbium seven.

  • 3.
    What was the largest number of quadrupoles connected in series for tandem mass spectrometry in a commercial instrument?

    Your answer:
    Correct answer:
    A penta-quadrupole mass spectrometer contains three quadrupole filters and two rf-only quadrupole collision cells. It allows MS3 experiments.  Extrel once offered such a spectrometer.

  • 4.
    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.

  • 5.
    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).

  • 6.
    Joseph John Thomson (1856 - 1940), Nobel laureate in physics, is credited with the invention of the mass spectrometer, the discovery of the electron and isotopes of stable elements. A lesser-known fact is his father's profession. What was it?

    Your answer:
    Correct answer:

    His father, Joseph James Thomson, ran an antiquarian bookshop founded by Thomson’s great-grandfather. [Wikipedia]

  • 7.
    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).

  • 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.
    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).

  • 10.
    The first on-line coupling of gas chromatography to a mass spectrometer was reported in 1959. What type of spectrometer was used for this purpose?

    Your answer:
    Correct answer:
    The first GC/MS experiments were carried out by Fred McLafferty and Roland Gohlke at Dow Chemical with Bill Wiley and Ian McLaren at Bendix Research Laboratories. They used a Bendix timeof- flight mass spectrometer, which had been commercially introduced in 1956. The instrument was fast enough to keep up with the changing output of the GC column.

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