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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 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.
  • 2.
    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.
  • 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.
    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.
  • 5.
    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.

  • 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.
    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.

  • 8.
    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.
  • 9.
    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.
  • 10.
    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.

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