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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.
    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).

  • 3.
    What ionization technique was used for the first sequencing of peptides by mass spectrometry?

    Your answer:
    Correct answer:

    Mass spectrometry was used to sequence peptides for the first time in 1959 when K. Biemann described an innovative method based on the reduction of small peptides to polyamino alcohols with characteristic EI spectra. [https://doi.org/10.1021/ja01518a069]

  • 4.
    Until 2019, the kilogram unit was defined using an international prototype kept at the International Bureau of Weights and Measures in France. The International Prototype of the Kilogram was made of an alloy of platinum and one other metal. The metal was:

    Your answer:
    Correct answer:

    The International Prototype of the Kilogram was a cylinder with a height and diameter of 39 mm made of an alloy of 90% platinum and 10% iridium.

  • 5.
    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.

  • 6.
    What is the trajectory of a charged particle moving parallel to a uniform electric field in a vacuum?

    Your answer:
    Correct answer:

    If a positive charge is moving in the same direction as the electric field vector the particle's velocity will increase. If it is moving in the opposite direction it will decelerate. If a negative charge is moving in the same direction as the electric field vector the particle will decelerate. If it is moving in the opposite direction it will accelerate.

  • 7.
    How many elements of the periodic table have only a single stable isotope?

    Your answer:
    Correct answer:
    These so-called monoisotopic elements are beryllium, fluorine, sodium, aluminum, phosphorus, scandium, vanadium, manganese, cobalt, arsenic, rubidium, yttrium, niobium, rhodium, indium, iodine, cesium, lanthanum, praseodymium, europium, terbium, holmium, thulium, lutecium, rhenium, and gold.

  • 8.
    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.

  • 9.
    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]

  • 10.
    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.

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