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Mass Spectrometry Quiz

Mass Spectrometry Quiz

Test your knowledge on mass spectrometry and its history

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  • 1.
    Which mass spectrometer was carried by the American spacecraft Viking 1 sent to the planet Mars in 1975?

    Your answer:
    Correct answer:
    Viking 1 carried two mass spectrometers, both equipped with double-focusing analyzers and electron ionization sources. The first spectrometer with a Mattauch-Herzog geometry was designed by Alfred Nier; it was intended to analyze the upper atmosphere of Mars. The second one with a Nier- Johnson geometry was part of the GC/MS apparatus designed by Klaus Biemann. It was used to analyze the regolith and the atmosphere at the landing site.
  • 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.
    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]

  • 4.
    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.

  • 5.
    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.
  • 6.
    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.

  • 7.
    Who built the first mass spectrometer in Czechia?

    Your answer:
    Correct answer:

    The first mass spectrometer in the country was built in the Laboratory of Physical Chemistry of the Czechoslovak Academy of Sciences. Four young scientists, Vladimír Čermák, Vladimír Hanuš, Čestmír Jech and Josef Cabicar, took part in its construction. At the time of the post-war shortage, it was very difficult to find the necessary components; some parts originated from captured German military equipment. The mass spectrometer was of the Nier type with simple focusing and 60° magnetic field, pumped by a mercury diffusion pump. The device was completed after two years, in 1953. The construction of this instrument was an extraordinary achievement awarded a year later by the State Prize. [Z. Herman, Chem. Listy 104, 955, 2010]

  • 8.
    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.

  • 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.
    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]

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