History of mass spectrometry

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Replica of F. W. Aston's third mass spectrograph. Early Mass Spectrometer (replica).jpg
Replica of F. W. Aston's third mass spectrograph.
A mass spectrometer in use at NIH in 1975 Mass Spectrometer at NIH (24549823931).jpg
A mass spectrometer in use at NIH in 1975

The history of mass spectrometry has its roots in physical and chemical studies regarding the nature of matter. The study of gas discharges in the mid 19th century led to the discovery of anode and cathode rays, which turned out to be positive ions and electrons. Improved capabilities in the separation of these positive ions enabled the discovery of stable isotopes of the elements. The first such discovery was with the element neon, which was shown by mass spectrometry to have at least two stable isotopes: 20Ne (neon with 10 protons and 10 neutrons) and 22Ne (neon with 10 protons and 12 neutrons). Mass spectrometers were used in the Manhattan Project for the separation of isotopes of uranium necessary to create the atomic bomb. [1]

Contents

Prout's Hypothesis

Prout's hypothesis was an early 19th-century attempt to explain the properties of the chemical elements using the internal structure of the atom. In 1815, the English chemist William Prout observed that the atomic weights that had been measured were integer multiples of the atomic weight of hydrogen. [2] [3] Prout's hypothesis remained influential in chemistry throughout the 1820s. However, more careful measurements of the atomic weights, such as those compiled by Jöns Jakob Berzelius in 1828 or Edward Turner in 1832, appeared to disprove it. In particular the atomic weight of chlorine, which is 35.45 times that of hydrogen, could not at the time be explained in terms of Prout's hypothesis. It would take the better part of a century for this problem to be resolved.

Canal rays

Canal ray (anode ray) tube Anode Ray Tube.jpg
Canal ray (anode ray) tube

In the mid-nineteenth century, Julius Plücker investigated the light emitted in discharge tubes and the influence of magnetic fields on the glow. [4] Later, in 1869, Johann Wilhelm Hittorf studied discharge tubes with energy rays extending from a negative electrode, the cathode. These rays produced a fluorescence when they hit a tube's glass walls, and when interrupted by a solid object they cast a shadow.

Canal rays, also called anode rays, were observed by Eugen Goldstein, in 1886. Goldstein used a gas discharge tube which had a perforated cathode. The rays are produced in the holes (canals) in the cathode and travels in a direction opposite to the "cathode rays," which are streams of electrons. Goldstein called these positive rays "Kanalstrahlen" - canal rays.

Discovery of isotopes

In the bottom right corner of this photographic plate are markings for the two isotopes of neon: neon-20 and neon-22. Discovery of neon isotopes.JPG
In the bottom right corner of this photographic plate are markings for the two isotopes of neon: neon-20 and neon-22.

In 1913, as part of his exploration into the composition of canal rays, J. J. Thomson channeled a stream of ionized neon through a magnetic and an electric field and measured its deflection by placing a photographic plate in its path. Thomson observed two patches of light on the photographic plate (see image on left), which suggested two different parabolas of deflection. Thomson concluded that the neon gas was composed of atoms of two different atomic masses (neon-20 and neon-22). [5]

Thomson's student Francis William Aston [6] continued the research at the Cavendish Laboratory in Cambridge, building the first full functional mass spectrometer that was reported in 1919. [7] He was able to identify isotopes of chlorine (35 and 37), bromine (79 and 81), and krypton (78, 80, 82, 83, 84 and 86), proving that these natural occurring elements are composed of a combination of isotopes. The use of electromagnetic focusing in mass spectrograph which rapidly allowed him to identify no fewer than 212 of the 287 naturally occurring isotopes. In 1921, F. W. Aston became a fellow of the Royal Society and received a Nobel Prize in Chemistry in the following year.

His work on isotopes also led to his formulation of the Whole Number Rule which states that "the mass of the oxygen isotope being defined [as 16], all the other isotopes have masses that are very nearly whole numbers," a rule that was used extensively in the development of nuclear energy. The exact mass of many isotopes was measured leading to the result that hydrogen has a 1% higher mass than expected by the average mass of the other elements. Aston speculated about the subatomic energy and the use of it in 1936.

In 1918, Arthur Jeffrey Dempster [8] reported on his mass spectrometer and established the basic theory and design of mass spectrometers that is still used to this day. Dempster's research over his career centered around the mass spectrometer and its applications, leading in 1935 to his discovery of the uranium isotope 235U. This isotope's ability to cause a rapidly expanding fission nuclear chain reaction allowed the development of the atom bomb and nuclear power.

In 1932, Kenneth Bainbridge developed a mass spectrometer with a resolving power of 600 and a relative precision of one part in 10,000. [9] He used this instrument to verify the equivalence of mass and energy, E = mc2. [10]

Manhattan Project

Calutron mass spectrometers at the Y-12 Plant in Oak Ridge, Tennessee ca. 1945 Alpha 1 racetrack, Uranium 235 electromagnetic separation plant, Manhattan Project, Y-12 Oak Ridge.jpg
Calutron mass spectrometers at the Y-12 Plant in Oak Ridge, Tennessee ca. 1945

A Calutron is a sector mass spectrometer that was used for separating the isotopes of uranium developed by Ernest O. Lawrence [11] during the Manhattan Project and was similar to the Cyclotron invented by Lawrence. Its name is a concatenation of Cal. U.-tron, in tribute to the University of California, Lawrence's institution and the contractor of the Los Alamos laboratory. [12] They were implemented for industrial scale uranium enrichment at the Oak Ridge, Tennessee Y-12 plant established during the war and provided much of the uranium used for the "Little Boy" nuclear weapon, which was dropped onto Hiroshima in 1945.

Development of gas chromatography-mass spectrometry

The use of a mass spectrometer as the detector in gas chromatography was developed during the 1950s by Roland Gohlke and Fred McLafferty. [13] [14] [15] The development of affordable and miniaturized computers has helped in the simplification of the use of this instrument, as well as allowed great improvements in the amount of time it takes to analyze a sample.

Fourier transform mass spectrometry

Fourier transform ion cyclotron resonance mass spectrometry was developed by Alan G. Marshall and Melvin B. Comisarow at the University of British Columbia in 1974. [16] The inspiration was earlier developments in conventional ICR and Fourier Transform Nuclear Magnetic Resonance (FT-NMR) spectroscopy.

Soft ionization methods

Single quadrupole mass spectrometer used for John Fenn's Nobel Prize winning work on electrospray ionization Fenn ESI Instrument.jpg
Single quadrupole mass spectrometer used for John Fenn's Nobel Prize winning work on electrospray ionization

Field desorption ionization was first reported by Beckey in 1969. [17] In field ionization, a high-potential electric field is applied to an emitter with a sharp surface, such as a razor blade, or more commonly, a filament from which tiny "whiskers" have been grown. This produces a very high electric field in which electron tunneling can result in ionization of gaseous analyte molecules. FI produces mass spectra with little or no fragmentation, dominated by molecular radical cations M+. and occasionally protonated molecules .

Chemical ionization was developed in the 1960s. [18] [19] [20] Ionization of sample (analyte) is achieved by interaction of its molecules with reagent ions. The analyte is ionized by ion-molecule reactions during collisions in the source. The process may involve transfer of an electron, a proton or other charged species between the reactants. This is a less energetic procedure than electron ionization and the ions produced are, for example, protonated molecules: [M + H]+. These ions are often relatively stable, tending not to fragment as readily as ions produced by electron ionization.

Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique used in mass spectrometry, allowing the analysis of biomolecules (biopolymers such as proteins, peptides and sugars) and large organic molecules (such as polymers, dendrimers and other macromolecules), which tend to be fragile and fragment when ionized by more conventional ionization methods. It is most similar in character to electrospray ionization both in relative softness and the ions produced (although it causes much fewer multiply charged ions). The term was first used in 1985 by Franz Hillenkamp, Michael Karas and their colleagues. [21] These researchers found that the amino acid alanine could be ionized more easily if it was mixed with the amino acid tryptophan and irradiated with a pulsed 266 nm laser. The tryptophan was absorbing the laser energy and helping to ionize the non-absorbing alanine. Peptides up to the 2843 Da peptide melittin could be ionized when mixed with this kind of “matrix”. [22]

The breakthrough for large molecule laser desorption ionization came in 1987 when Koichi Tanaka of Shimadzu Corp. and his co-workers used what they called the “ultra fine metal plus liquid matrix method” that combined 30 nm cobalt particles in glycerol with a 337 nm nitrogen laser for ionization. [23] Using this laser and matrix combination, Tanaka was able to ionize biomolecules as large as the 34,472 Da protein carboxypeptidase-A. Tanaka received one-quarter of the 2002 Nobel Prize in Chemistry for demonstrating that, with the proper combination of laser wavelength and matrix, a protein can be ionized. [24] Karas and Hillenkamp were subsequently able to ionize the 67 kDa protein albumin using a nicotinic acid matrix and a 266 nm laser. [25] Further improvements were realized through the use of a 355 nm laser and the cinnamic acid derivatives ferulic acid, caffeic acid and sinapinic acid as the matrix. [26] The availability of small and relatively inexpensive nitrogen lasers operating at 337 nm wavelength and the first commercial instruments introduced in the early 1990s brought MALDI to an increasing number of researchers. [27] Today, mostly organic matrices are used for MALDI mass spectrometry.

Timeline

19th century

1886
Eugen Goldstein observes canal rays.
1898
Wilhelm Wien Wilhelm Wien.jpg
Wilhelm Wien
Wilhelm Wien demonstrates that canal rays can be deflected using strong electric and magnetic fields. He shows that the mass-to-charge ratio of the particles have opposite polarity and is much larger compared to the electron. He also realizes that the particle mass is similar to the one of hydrogen particle.
1898
J. J. Thomson measures the mass-to-charge ratio of electrons.

20th century

1901
Walter Kaufmann uses a mass spectrometer to measure the relativistic mass increase of electrons.
1905
J. J. Thomson begins his study of positive rays.
1906
Thomson is awarded the Nobel Prize in Physics "in recognition of the great merits of his theoretical and experimental investigations on the conduction of electricity by gases"
1913
Thomson is able to separate particles of different mass-to-charge ratios. He separates the 20Ne and the 22Ne isotopes, and he correctly identifies the m/z = 11 signal as a doubly charged 22Ne particle. [28]
1919
Francis Aston constructs the first velocity focusing mass spectrograph with mass resolving power of 130.
1922
Aston is awarded the Nobel Prize in chemistry "for his discovery, by means of his mass spectrograph, of isotopes, in a large number of non-radioactive elements, and for his enunciation of the whole-number rule."
1931
Ernest O. Lawrence Ernest Orlando Lawrence.jpg
Ernest O. Lawrence
Ernest O. Lawrence invents the cyclotron.
1934
Josef Mattauch and Richard Herzog develop the double-focusing mass spectrograph.
1936
Arthur J. Dempster develops the spark ionization source.
1937
Aston constructs a mass spectrograph with resolving power of 2000.
1939
Lawrence receives the Nobel Prize in Physics for the cyclotron.
1942
Lawrence develops the Calutron for uranium isotope separation.
1943
Westinghouse markets its mass spectrometer and proclaims it to be "A New Electronic Method for fast, accurate gas analysis".
1946
William Stephens presents the concept of a time-of-flight mass spectrometer.
1953
Wolfgang Paul and Helmut Steinwedel introduce the quadrupole mass filter.
1954
A. J. C. Nicholson (Australia) proposes a hydrogen transfer reaction that will come to be known as the McLafferty rearrangement. [29]
1959
Researchers at Dow Chemical interface a gas chromatograph to a mass spectrometer.
1964
British Mass Spectrometry Society established as first dedicated mass spectrometry society. It holds its first meeting in 1965 in London.
1966
F. H. Field and M. S. B. Munson develop chemical ionization.
1968
Malcolm Dole develops electrospray ionization.
1969
H. D. Beckey develops field desorption.
1974
Comisarow and Marshall develop Fourier Transform Ion Cyclotron Resonance mass spectrometry.
1976
Ronald MacFarlane and co-workers develop plasma desorption mass spectrometry.
1984
John Bennett Fenn and co-workers use electrospray to ionize biomolecules.
1985
Franz Hillenkamp, Michael Karas and co-workers describe and coin the term matrix-assisted laser desorption ionization (MALDI).
1987
Koichi Tanaka uses the “ultra fine metal plus liquid matrix method” to ionize intact proteins.
1989
Wolfgang Paul receives the Nobel Prize in Physics "for the development of the ion trap technique".
1999
Alexander Makarov presents the Orbitrap mass spectrometer. [30]

21st century

2002

John Bennett Fenn and Koichi Tanaka are awarded one-quarter of the Nobel Prize in chemistry each "for the development of soft desorption ionisation methods ... for mass spectrometric analyses of biological macromolecules."

2005
Commercialization of Orbitrap MS
2008
ASMS Distinguished Contribution in Mass Spectrometry Award

See also

Related Research Articles

Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures.

<span class="mw-page-title-main">Ion source</span> Device that creates charged atoms and molecules (ions)

An ion source is a device that creates atomic and molecular ions. Ion sources are used to form ions for mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters and ion engines.

<span class="mw-page-title-main">Electrospray ionization</span> Technique used in mass spectroscopy

Electrospray ionization (ESI) is a technique used in mass spectrometry to produce ions using an electrospray in which a high voltage is applied to a liquid to create an aerosol. It is especially useful in producing ions from macromolecules because it overcomes the propensity of these molecules to fragment when ionized. ESI is different from other ionization processes since it may produce multiple-charged ions, effectively extending the mass range of the analyser to accommodate the kDa-MDa orders of magnitude observed in proteins and their associated polypeptide fragments.

<span class="mw-page-title-main">Mass spectrum</span> Tool in chemical analysis

A mass spectrum is a histogram plot of intensity vs. mass-to-charge ratio (m/z) in a chemical sample, usually acquired using an instrument called a mass spectrometer. Not all mass spectra of a given substance are the same; for example, some mass spectrometers break the analyte molecules into fragments; others observe the intact molecular masses with little fragmentation. A mass spectrum can represent many different types of information based on the type of mass spectrometer and the specific experiment applied. Common fragmentation processes for organic molecules are the McLafferty rearrangement and alpha cleavage. Straight chain alkanes and alkyl groups produce a typical series of peaks: 29 (CH3CH2+), 43 (CH3CH2CH2+), 57 (CH3CH2CH2CH2+), 71 (CH3CH2CH2CH2CH2+) etc.

<span class="mw-page-title-main">Francis William Aston</span> British scientist

Francis William Aston FRS was a British chemist and physicist who won the 1922 Nobel Prize in Chemistry for his discovery, by means of his mass spectrograph, of isotopes in many non-radioactive elements and for his enunciation of the whole number rule. He was a fellow of the Royal Society and Fellow of Trinity College, Cambridge.

<span class="mw-page-title-main">Koichi Tanaka</span> Japanese electrical engineer (born 1959)

Koichi Tanaka is a Japanese electrical engineer who shared the Nobel Prize in Chemistry in 2002 for developing a novel method for mass spectrometric analyses of biological macromolecules with John Bennett Fenn and Kurt Wüthrich.

<span class="mw-page-title-main">Matrix-assisted laser desorption/ionization</span> Ionization technique

In mass spectrometry, matrix-assisted laser desorption/ionization (MALDI) is an ionization technique that uses a laser energy absorbing matrix to create ions from large molecules with minimal fragmentation. It has been applied to the analysis of biomolecules and various organic molecules, which tend to be fragile and fragment when ionized by more conventional ionization methods. It is similar in character to electrospray ionization (ESI) in that both techniques are relatively soft ways of obtaining ions of large molecules in the gas phase, though MALDI typically produces far fewer multi-charged ions.

Soft laser desorption (SLD) is laser desorption of large molecules that results in ionization without fragmentation. "Soft" in the context of ion formation means forming ions without breaking chemical bonds. "Hard" ionization is the formation of ions with the breaking of bonds and the formation of fragment ions.

<span class="mw-page-title-main">3-Nitrobenzyl alcohol</span> Chemical compound

The compound 3-nitrobenzyl alcohol is an organic compound with the formula C7H7NO3.

<span class="mw-page-title-main">Protein mass spectrometry</span> Application of mass spectrometry

Protein mass spectrometry refers to the application of mass spectrometry to the study of proteins. Mass spectrometry is an important method for the accurate mass determination and characterization of proteins, and a variety of methods and instrumentations have been developed for its many uses. Its applications include the identification of proteins and their post-translational modifications, the elucidation of protein complexes, their subunits and functional interactions, as well as the global measurement of proteins in proteomics. It can also be used to localize proteins to the various organelles, and determine the interactions between different proteins as well as with membrane lipids.

<span class="mw-page-title-main">Desorption electrospray ionization</span>

Desorption electrospray ionization (DESI) is an ambient ionization technique that can be coupled to mass spectrometry (MS) for chemical analysis of samples at atmospheric conditions. Coupled ionization sources-MS systems are popular in chemical analysis because the individual capabilities of various sources combined with different MS systems allow for chemical determinations of samples. DESI employs a fast-moving charged solvent stream, at an angle relative to the sample surface, to extract analytes from the surfaces and propel the secondary ions toward the mass analyzer. This tandem technique can be used to analyze forensics analyses, pharmaceuticals, plant tissues, fruits, intact biological tissues, enzyme-substrate complexes, metabolites and polymers. Therefore, DESI-MS may be applied in a wide variety of sectors including food and drug administration, pharmaceuticals, environmental monitoring, and biotechnology.

Sample preparation for mass spectrometry is used for the optimization of a sample for analysis in a mass spectrometer (MS). Each ionization method has certain factors that must be considered for that method to be successful, such as volume, concentration, sample phase, and composition of the analyte solution. Quite possibly the most important consideration in sample preparation is knowing what phase the sample must be in for analysis to be successful. In some cases the analyte itself must be purified before entering the ion source. In other situations, the matrix, or everything in the solution surrounding the analyte, is the most important factor to consider and adjust. Often, sample preparation itself for mass spectrometry can be avoided by coupling mass spectrometry to a chromatography method, or some other form of separation before entering the mass spectrometer. In some cases, the analyte itself must be adjusted so that analysis is possible, such as in protein mass spectrometry, where usually the protein of interest is cleaved into peptides before analysis, either by in-gel digestion or by proteolysis in solution.

<span class="mw-page-title-main">Laser spray ionization</span>

Laser spray ionization refers to one of several methods for creating ions using a laser interacting with a spray of neutral particles or ablating material to create a plume of charged particles. The ions thus formed can be separated by m/z with mass spectrometry. Laser spray is one of several ion sources that can be coupled with liquid chromatography-mass spectrometry for the detection of larger molecules.

<span class="mw-page-title-main">Matrix-assisted laser desorption electrospray ionization</span>

Matrix-assisted laser desorption electrospray ionization (MALDESI) was first introduced in 2006 as a novel ambient ionization technique which combines the benefits of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). An infrared (IR) or ultraviolet (UV) laser can be utilized in MALDESI to resonantly excite an endogenous or exogenous matrix. The term ‘matrix’ refers to any molecule that is present in large excess and absorbs the energy of the laser, thus facilitating desorption of analyte molecules. The original MALDESI design was implemented using common organic matrices, similar to those used in MALDI, along with a UV laser. The current MALDESI source employs endogenous water or a thin layer of exogenously deposited ice as the energy-absorbing matrix where O-H symmetric and asymmetric stretching bonds are resonantly excited by a mid-IR laser.

<span class="mw-page-title-main">Desorption atmospheric pressure photoionization</span>

Desorption atmospheric pressure photoionization (DAPPI) is an ambient ionization technique for mass spectrometry that uses hot solvent vapor for desorption in conjunction with photoionization. Ambient Ionization techniques allow for direct analysis of samples without pretreatment. The direct analysis technique, such as DAPPI, eliminates the extraction steps seen in most nontraditional samples. DAPPI can be used to analyze bulkier samples, such as, tablets, powders, resins, plants, and tissues. The first step of this technique utilizes a jet of hot solvent vapor. The hot jet thermally desorbs the sample from a surface. The vaporized sample is then ionized by the vacuum ultraviolet light and consequently sampled into a mass spectrometer. DAPPI can detect a range of both polar and non-polar compounds, but is most sensitive when analyzing neutral or non-polar compounds. This technique also offers a selective and soft ionization for highly conjugated compounds.

<span class="mw-page-title-main">Ambient ionization</span>

Ambient ionization is a form of ionization in which ions are formed in an ion source outside the mass spectrometer without sample preparation or separation. Ions can be formed by extraction into charged electrospray droplets, thermally desorbed and ionized by chemical ionization, or laser desorbed or ablated and post-ionized before they enter the mass spectrometer.

<span class="mw-page-title-main">Franz Hillenkamp</span>

Franz Hillenkamp was a German scientist known for his development of the laser microprobe mass analyzer and, with Michael Karas, matrix-assisted laser desorption/ionization (MALDI).

A laser microprobe mass spectrometer (LMMS), also laser microprobe mass analyzer (LAMMA), laser ionization mass spectrometer (LIMS), or laser ionization mass analyzer (LIMA) is a mass spectrometer that uses a focused laser for microanalysis. It employs local ionization by a pulsed laser and subsequent mass analysis of the generated ions.

In mass spectrometry, a matrix is a compound that promotes the formation of ions. Matrix compounds are used in matrix-assisted laser desorption/ionization (MALDI), matrix-assisted ionization (MAI), and fast atom bombardment (FAB).

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