Ion source

Last updated

Mass spectrometer EI/CI ion source Mass spectrometer ei ci ion source.jpg
Mass spectrometer EI/CI ion source

An ion source is a device that creates atomic and molecular ions. [1] Ion sources are used to form ions for mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters and ion engines.

Contents

Electron ionization

Electron ionization source schematic Schematic diagram of an EI ion source.jpg
Electron ionization source schematic

Electron ionization is widely used in mass spectrometry, particularly for organic molecules. The gas phase reaction producing electron ionization is

where M is the atom or molecule being ionized, is the electron, and is the resulting ion.

The electrons may be created by an arc discharge between a cathode and an anode.

An electron beam ion source (EBIS) is used in atomic physics to produce highly charged ions by bombarding atoms with a powerful electron beam. [2] [3] Its principle of operation is shared by the electron beam ion trap.

Electron capture ionization

Electron capture ionization (ECI) is the ionization of a gas phase atom or molecule by attachment of an electron to create an ion of the form A−•. The reaction is

where the M over the arrow denotes that to conserve energy and momentum a third body is required (the molecularity of the reaction is three).

Electron capture can be used in conjunction with chemical ionization. [4]

An electron capture detector is used in some gas chromatography systems. [5]

Chemical ionization

Chemical ionization (CI) is a lower energy process than electron ionization because it involves ion/molecule reactions rather than electron removal. [6] The lower energy yields less fragmentation, and usually a simpler spectrum. A typical CI spectrum has an easily identifiable molecular ion. [7]

In a CI experiment, ions are produced through the collision of the analyte with ions of a reagent gas in the ion source. Some common reagent gases include: methane, ammonia, and isobutane. Inside the ion source, the reagent gas is present in large excess compared to the analyte. Electrons entering the source will preferentially ionize the reagent gas. The resultant collisions with other reagent gas molecules will create an ionization plasma. Positive and negative ions of the analyte are formed by reactions with this plasma. For example, protonation occurs by

(primary ion formation),
(reagent ion formation),
(product ion formation, e.g. protonation).

Charge exchange ionization

Charge-exchange ionization (also known as charge-transfer ionization) is a gas phase reaction between an ion and an atom or molecule in which the charge of the ion is transferred to the neutral species. [8]

Chemi-ionization

Chemi-ionization is the formation of an ion through the reaction of a gas phase atom or molecule with an atom or molecule in an excited state. [9] [10] Chemi-ionization can be represented by

where G is the excited state species (indicated by the superscripted asterisk), and M is the species that is ionized by the loss of an electron to form the radical cation (indicated by the superscripted "plus-dot").

Associative ionization

Associative ionization is a gas phase reaction in which two atoms or molecules interact to form a single product ion. [11] [12] [13] One or both of the interacting species may have excess internal energy.

For example,

where species A with excess internal energy (indicated by the asterisk) interacts with B to form the ion AB+.

Penning ionization

Penning ionization is a form of chemi-ionization involving reactions between neutral atoms or molecules. [14] [15] The process is named after the Dutch physicist Frans Michel Penning who first reported it in 1927. [16] Penning ionization involves a reaction between a gas-phase excited-state atom or molecule G* and a target molecule M resulting in the formation of a radical molecular cation M+., an electron e−, and a neutral gas molecule G: [17]

Penning ionization occurs when the target molecule has an ionization potential lower than the internal energy of the excited-state atom or molecule.

Associative Penning ionization can proceed via

Surface Penning ionization (also known as Auger deexcitation) refers to the interaction of the excited-state gas with a bulk surface S, resulting in the release of an electron according to

.

Ion attachment

Ion-attachment ionization is similar to chemical ionization in which a cation is attached to the analyte molecule in a reactive collision:

Where M is the analyte molecule, X+ is the cation and A is a non-reacting collision partner. [18]

In a radioactive ion source, a small piece of radioactive material, for instance 63 Ni or 241 Am, is used to ionize a gas.[ citation needed ] This is used in ionization smoke detectors and ion mobility spectrometers.

Gas-discharge ion sources

NASA's NEXT (ion thruster) space craft propulsion system NASA NEXT Ion thruster.712983main NEXT LDT Thrusterhi-res full.jpg
NASA's NEXT (ion thruster) space craft propulsion system

These ion sources use a plasma source or electric discharge to create ions.

Inductively-coupled plasma

Ions can be created in an inductively coupled plasma, which is a plasma source in which the energy is supplied by electrical currents which are produced by electromagnetic induction, that is, by time-varying magnetic fields. [19]


Microwave-induced plasma

Microwave induced plasma ion sources are capable of exciting electrodeless gas discharges to create ions for trace element mass spectrometry. [20] [21] A microwave plasma has high frequency electromagnetic radiation in the GHz range. It is capable of exciting electrodeless gas discharges. If applied in surface-wave-sustained mode, they are especially well suited to generate large-area plasmas of high plasma density. If they are both in surface-wave and resonator mode, they can exhibit a high degree of spatial localization. This allows to spatially separate the location of plasma generations from the location of surface processing. Such a separation (together with an appropriate gas-flow scheme) may help reduce the negative effect, that particles released from a processed substrate may have on the plasma chemistry of the gas phase.

ECR ion source

The ECR ion source makes use of the electron cyclotron resonance to ionize a plasma. Microwaves are injected into a volume at the frequency corresponding to the electron cyclotron resonance, defined by the magnetic field applied to a region inside the volume. The volume contains a low pressure gas.

Glow discharge

Capillaritron with quartz capillary in operation within a vacuum chamber: On the left the glowing capillary with the plasma up to the extraction cathode and on the right behind it the bluish glowing ion beam. Quarzkapillaritron.Betrieb.jpg
Capillaritron with quartz capillary in operation within a vacuum chamber: On the left the glowing capillary with the plasma up to the extraction cathode and on the right behind it the bluish glowing ion beam.

Ions can be created in an electric glow discharge. A glow discharge is a plasma formed by the passage of electric current through a low-pressure gas. It is created by applying a voltage between two metal electrodes in an evacuated chamber containing gas. When the voltage exceeds a certain value, called the striking voltage, the gas forms a plasma.

A duoplasmatron is a type of glow discharge ion source that consists of a hot cathode or cold cathode that produces a plasma that is used to ionize a gas. [1] [22] THey can produce positive or negative ions. [23] They are used for secondary ion mass spectrometry, ion beam etching, and high-energy physics. [24] [25] [26]

Flowing afterglow

In a flowing plasma afterglow, ions are formed in a flow of inert gas, typically helium or argon. [27] [28] [29] Reagents are added downstream to create ion products and study reaction rates. Flowing-afterglow mass spectrometry is used for trace gas analysis for organic compounds. [30] [31]

Spark ionization

Electric spark ionization is used to produce gas phase ions from a solid sample. When incorporated with a mass spectrometer the complete instrument is referred to as a spark ionization mass spectrometer or as a spark source mass spectrometer (SSMS). [32]

A closed drift ion source uses a radial magnetic field in an annular cavity in order to confine electrons for ionizing a gas. They are used for ion implantation and for space propulsion (Hall-effect thrusters).

Photoionization

Photoionization is the ionization process in which an ion is formed from the interaction of a photon with an atom or molecule. [33]

Multi-photon ionization

In multi-photon ionization (MPI), several photons of energy below the ionization threshold may actually combine their energies to ionize an atom.

Resonance-enhanced multiphoton ionization (REMPI) is a form of MPI in which one or more of the photons accesses a bound-bound transition that is resonant in the atom or molecule being ionized.

Atmospheric pressure photoionization

Atmospheric pressure photoionization (APPI) uses a source of photons, usually a vacuum UV (VUV) lamp, to ionize the analyte with single photon ionization process. Analogous to other atmospheric pressure ion sources, a spray of solvent is heated to relatively high temperatures (above 400 degrees Celsius) and sprayed with high flow rates of nitrogen for desolvation. The resulting aerosol is subjected to UV radiation to create ions. Atmospheric-pressure laser ionization uses UV laser light sources to ionize the analyte via MPI.

Desorption ionization

Field desorption

Field desorption schematic Field desorption.gif
Field desorption schematic

Field desorption refers to an ion source in which 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 formed. [34] This results in a very high electric field which can result in ionization of gaseous molecules of the analyte. Mass spectra produced by FI have little or no fragmentation. They are dominated by molecular radical cations M+. and less often, protonated molecules [M + H]+

Particle bombardment

Fast atom bombardment

Particle bombardment with atoms is called fast atom bombardment (FAB) and bombardment with atomic or molecular ions is called secondary ion mass spectrometry (SIMS). [35] Fission fragment ionization uses ionic or neutral atoms formed as a result of the nuclear fission of a suitable nuclide, for example the Californium isotope 252Cf.

In FAB the analytes is mixed with a non-volatile chemical protection environment called a matrix and is bombarded under vacuum with a high energy (4000 to 10,000 electron volts) beam of atoms. [36] The atoms are typically from an inert gas such as argon or xenon. Common matrices include glycerol, thioglycerol, 3-nitrobenzyl alcohol (3-NBA), 18-crown-6 ether, 2-nitrophenyloctyl ether, sulfolane, diethanolamine, and triethanolamine. This technique is similar to secondary ion mass spectrometry and plasma desorption mass spectrometry.

Secondary ionization

Secondary ion mass spectrometry (SIMS) is used to analyze the composition of solid surfaces and thin films by sputtering the surface of the specimen with a focused primary ion beam and collecting and analyzing ejected secondary ions. The mass/charge ratios of these secondary ions are measured with a mass spectrometer to determine the elemental, isotopic, or molecular composition of the surface to a depth of 1 to 2 nm.

In a liquid metal ion source (LMIS), a metal (typically gallium) is heated to the liquid state and provided at the end of a capillary or a needle. Then a Taylor cone is formed under the application of a strong electric field. As the cone's tip get sharper, the electric field becomes stronger, until ions are produced by field evaporation. These ion sources are particularly used in ion implantation or in focused ion beam instruments.

Plasma desorption ionization

Schematic representation of a plasama desorption time-of-flight mass spectrometer Pdms inst.gif
Schematic representation of a plasama desorption time-of-flight mass spectrometer

Plasma desorption ionization mass spectrometry (PDMS), also called fission fragment ionization, is a mass spectrometry technique in which ionization of material in a solid sample is accomplished by bombarding it with ionic or neutral atoms formed as a result of the nuclear fission of a suitable nuclide, typically the californium isotope 252Cf. [37] [38]

Laser desorption ionization

Diagram of a MALDI ion source Maldi.PNG
Diagram of a MALDI ion source

Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique. The sample is mixed with a matrix material. Upon receiving a laser pulse, the matrix absorbs the laser energy and it is thought that primarily the matrix is desorbed and ionized (by addition of a proton) by this event. The analyte molecules are also desorbed. The matrix is then thought to transfer proton to the analyte molecules (e.g., protein molecules), thus charging the analyte.

Surface-assisted laser desorption/ionization

Surface-assisted laser desorption/ionization (SALDI) is a soft laser desorption technique used for analyzing biomolecules by mass spectrometry. [39] [40] In its first embodiment, it used graphite matrix. [39] At present, laser desorption/ionization methods using other inorganic matrices, such as nanomaterials, are often regarded as SALDI variants. A related method named "ambient SALDI" - which is a combination of conventional SALDI with ambient mass spectrometry incorporating the DART ion source - has also been demonstrated. [41]

Surface-enhanced laser desorption/ionization

Surface-enhanced laser desorption/ionization (SELDI) is a variant of MALDI that is used for the analysis of protein mixtures that uses a target modified to achieve biochemical affinity with the analyte compound. [42]

Desorption ionization on silicon

Desorption ionization on silicon (DIOS) refers to laser desorption/ionization of a sample deposited on a porous silicon surface. [43]

Smalley source

A laser vaporization cluster source produces ions using a combination of laser desorption ionization and supersonic expansion. [44] The Smalley source (or Smalley cluster source) [45] was developed by Richard Smalley at Rice University in the 1980s and was central to the discovery of fullerenes in 1985. [46] [47]

Aerosol ionization

In aerosol mass spectrometry with time-of-flight analysis, micrometer sized solid aerosol particles extracted from the atmosphere are simultaneously desorbed and ionized by a precisely timed laser pulse as they pass through the center of a time-of-flight ion extractor. [48] [49]

Spray ionization

Atmospheric-pressure chemical ionization source Apci.png
Atmospheric-pressure chemical ionization source

Spray ionization methods involve the formation of aerosol particles from a liquid solution and the formation of bare ions after solvent evaporation. [50]

Solvent-assisted ionization (SAI) is a method in which charged droplets are produced by introducing a solution containing analyte into a heated inlet tube of an atmospheric pressure ionization mass spectrometer. Just as in Electrospray Ionization (ESI), desolvation of the charged droplets produces multiply charged analyte ions. Volatile and nonvolatile compounds are analyzed by SAI, and high voltage is not required to achieve sensitivity comparable to ESI. [51] Application of a voltage to the solution entering the hot inlet through a zero dead volume fitting connected to fused silica tubing produces ESI-like mass spectra, but with higher sensitivity. [52] The inlet tube to the mass spectrometer becomes the ion source.

Matrix-Assisted Ionization

Matrix-Assisted Ionization (MAI) is similar to MALDI in sample preparation, but a laser is not required to convert analyte molecules included in a matrix compound into gas-phase ions. In MAI, analyte ions have charge states similar to electrospray ionization but obtained from a solid matrix rather than a solvent. No voltage or laser is required, but a laser can be used to obtain spatial resolution for imaging. Matrix-analyte samples are ionized in the vacuum of a mass spectrometer and can be inserted into the vacuum through an atmospheric pressure inlet. Less volatile matrices such as 2,5-dihydroxybenzoic acid require a hot inlet tube to produce analyte ions by MAI, but more volatile matrices such as 3-nitrobenzonitrile require no heat, voltage, or laser. Simply introducing the matrix-analyte sample to the inlet aperture of an atmospheric pressure ionization mass spectrometer produces abundant ions. Compounds at least as large as bovine serum albumin [66 kDa] can be ionized with this method. [53] In this method, the inlet to the mass spectrometer can be considered the ion source.

Atmospheric-pressure chemical ionization

Atmospheric-pressure chemical ionization uses a solvent spray at atmospheric pressure. [54] A spray of solvent is heated to relatively high temperatures (above 400 degrees Celsius), sprayed with high flow rates of nitrogen and the entire aerosol cloud is subjected to a corona discharge that creates ions with the evaporated solvent acting as the chemical ionization reagent gas. APCI is not as "soft" (low fragmentation) an ionization technique as ESI. [55] Note that atmospheric pressure ionization (API) should not be used as a synonym for APCI. [56]

Thermospray ionization

Thermospray ionization is a form of atmospheric pressure ionization in mass spectrometry. It transfers ions from the liquid phase to the gas phase for analysis. It is particularly useful in liquid chromatography-mass spectrometry. [57]

Electrospray ion source NanoESIFT.jpg
Electrospray ion source

Electrospray ionization

In electrospray ionization, a liquid is pushed through a very small, charged and usually metal, capillary. [58] This liquid contains the substance to be studied, the analyte, dissolved in a large amount of solvent, which is usually much more volatile than the analyte. Volatile acids, bases or buffers are often added to this solution as well. The analyte exists as an ion in solution either in its anion or cation form. Because like charges repel, the liquid pushes itself out of the capillary and forms an aerosol, a mist of small droplets about 10 μm across. The aerosol is at least partially produced by a process involving the formation of a Taylor cone and a jet from the tip of this cone. An uncharged carrier gas such as nitrogen is sometimes used to help nebulize the liquid and to help evaporate the neutral solvent in the droplets. As the solvent evaporates, the analyte molecules are forced closer together, repel each other and break up the droplets. This process is called Coulombic fission because it is driven by repulsive Coulombic forces between charged molecules. The process repeats until the analyte is free of solvent and is a bare ion. The ions observed are created by the addition of a proton (a hydrogen ion) and denoted [M + H]+, or of another cation such as sodium ion, [M + Na]+, or the removal of a proton, [M − H]−. Multiply charged ions such as [M + 2H]2+ are often observed. For macromolecules, there can be many charge states, occurring with different frequencies; the charge can be as great as [M + 25H]25+, for example.[ citation needed ]

Probe electrospray ionization

Probe electrospray ionization (PESI) is a modified version of electrospray, where the capillary for sample solution transferring is replaced by a sharp-tipped solid needle with periodic motion. [59]

Contactless atmospheric pressure ionization

Contactless atmospheric pressure ionization is a technique used for analysis of liquid and solid samples by mass spectrometry. [60] Contactless API can be operated without an additional electric power supply (supplying voltage to the source emitter), gas supply, or syringe pump. Thus, the technique provides a facile means for analyzing chemical compounds by mass spectrometry at atmospheric pressure.

Sonic spray ionization

Sonic spray ionization is method for creating ions from a liquid solution, for example, a mixture of methanol and water. [61] A pneumatic nebulizer is used to turn the solution into a supersonic spray of small droplets. Ions are formed when the solvent evaporates and the statistically unbalanced charge distribution on the droplets leads to a net charge and complete desolvation results in the formation of ions. Sonic spray ionization is used to analyze small organic molecules and drugs and can analyze large molecules when an electric field is applied to the capillary to help increase the charge density and generate multiple charged ions of proteins. [62]

Sonic spray ionization has been coupled with high performance liquid chromatography for the analysis of drugs. [63] [64] Oligonucleotides have been studied with this method. [65] [66] SSI has been used in a manner similar to desorption electrospray ionization [67] for ambient ionization and has been coupled with thin-layer chromatography in this manner. [68]

Ultrasonication-assisted spray ionization

Ultrasonication-assisted spray ionization (UASI) is similar to the above techniques but uses an ultrasonic transducer to achieve atomization of the material and generate ions. [69] [70]

Thermal ionization

Thermal ionization (also known as surface ionization, or contact ionization) involves spraying vaporized, neutral atoms onto a hot surface, from which the atoms re-evaporate in ionic form. To generate positive ions, the atomic species should have a low ionization energy, and the surface should have a high work function. This technique is most suitable for alkali atoms (Li, Na, K, Rb, Cs) which have low ionization energies and are easily evaporated. [71]

To generate negative ions, the atomic species should have a high electron affinity, and the surface should have a low work function. This second approach is most suited for halogen atoms Cl, Br, I, At. [72]

Ambient ionization

Direct analysis in real time ambient ionization ion source DART ion source capsule.jpg
Direct analysis in real time ambient ionization ion source

In ambient ionization, ions are formed outside the mass spectrometer without sample preparation or separation. [73] [74] [75] 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.

Solid-liquid extraction based ambient ionization uses a charged spray to create a liquid film on the sample surface. [74] [76] Molecules on the surface are extracted into the solvent. The action of the primary droplets hitting the surface produces secondary droplets that are the source of ions for the mass spectrometer. Desorption electrospray ionization (DESI) creates charged droplets that are directed at a solid sample a few millimeters to a few centimeters away. The charged droplets pick up the sample through interaction with the surface and then form highly charged ions that can be sampled into a mass spectrometer. [77]

Plasma-based ambient ionization is based on an electrical discharge in a flowing gas that produces metastable atoms and molecules and reactive ions. Heat is often used to assist in the desorption of volatile species from the sample. Ions are formed by chemical ionization in the gas phase. A direct analysis in real time (DART) source operates by exposing the sample to a dry gas stream (typically helium or nitrogen) that contains long-lived electronically or vibronically excited neutral atoms or molecules (or "metastables"). Excited states are typically formed in the DART source by creating a glow discharge in a chamber through which the gas flows. A similar method called atmospheric solids analysis probe (ASAP) uses the heated gas from ESI or APCI probes to vaporize sample placed on a melting point tube inserted into an ESI/APCI source. [78] Ionization is by APCI.

Laser-based ambient ionization is a two-step process in which a pulsed laser is used to desorb or ablate material from a sample and the plume of material interacts with an electrospray or plasma to create ions. Electrospray-assisted laser desorption/ionization (ELDI) uses a 337 nm UV laser [79] or 3 μm infrared laser [80] to desorb material into an electrospray source. Matrix-assisted laser desorption electrospray ionization (MALDESI) [81] is an atmospheric pressure ionization source for generation of multiply charged ions. An ultraviolet or infrared laser is directed onto a solid or liquid sample containing the analyte of interest and matrix desorbing neutral analyte molecules that are ionized by interaction with electrosprayed solvent droplets generating multiply charged ions. Laser ablation electrospray ionization (LAESI) is an ambient ionization method for mass spectrometry that combines laser ablation from a mid-infrared (mid-IR) laser with a secondary electrospray ionization (ESI) process.

Applications

Mass spectrometry

In a mass spectrometer a sample is ionized in an ion source and the resulting ions are separated by their mass-to-charge ratio. The ions are detected and the results are displayed as spectra of the relative abundance of detected ions as a function of the mass-to-charge ratio. The atoms or molecules in the sample can be identified by correlating known masses to the identified masses or through a characteristic fragmentation pattern.

Particle accelerators

Surface ionization source at the Argonne Tandem Linear Accelerator System (ATLAS) CARIBU at ATLAS.jpg
Surface ionization source at the Argonne Tandem Linear Accelerator System (ATLAS)
Ion source used in the Cockcroft-Walton pre-accelerator at Fermilab Ion source at used in the Cockcroft-Walton accelerators at Fermilab.jpg
Ion source used in the Cockcroft-Walton pre-accelerator at Fermilab

In particle accelerators an ion source creates a particle beam at the beginning of the machine, the source. The technology to create ion sources for particle accelerators depends strongly on the type of particle that needs to be generated: electrons, protons, H− ion or a Heavy ions.

Electrons are generated with an electron gun, of which there are many varieties.

Protons are generated with a plasma-based device, like a duoplasmatron or a magnetron.

H− ions are generated with a magnetron or a Penning source. A magnetron consists of a central cylindrical cathode surrounded by an anode. The discharge voltage is typically greater than 150 V and the current drain is around 40 A. A magnetic field of about 0.2 tesla is parallel to the cathode axis. Hydrogen gas is introduced by a pulsed gas valve. Caesium is often used to lower the work function of the cathode, enhancing the amount of ions that are produced. Large caesiated sources are also used for plasma heating in nuclear fusion devices.

For a Penning source, a strong magnetic field parallel to the electric field of the sheath guides electrons and ions on cyclotron spirals from cathode to cathode. Fast H-minus ions are generated at the cathodes as in the magnetron. They are slowed down due to the charge exchange reaction as they migrate to the plasma aperture. This makes for a beam of ions that is colder than the ions obtained from a magnetron.

Heavy ions can be generated with an electron cyclotron resonance ion source. The use of electron cyclotron resonance (ECR) ion sources for the production of intense beams of highly charged ions has immensely grown over the last decade. ECR ion sources are used as injectors into linear accelerators, Van-de-Graaff generators or cyclotrons in nuclear and elementary particle physics. In atomic and surface physics ECR ion sources deliver intense beams of highly charged ions for collision experiments or for the investigation of surfaces. For the highest charge states, however, Electron beam ion sources (EBIS) are needed. They can generate even bare ions of mid-heavy elements. The Electron beam ion trap (EBIT), based on the same principle, can produce up to bare uranium ions and can be used as an ion source as well.

Heavy ions can also be generated with an ion gun which typically uses the thermionic emission of electrons to ionize a substance in its gaseous state. Such instruments are typically used for surface analysis.

Ion beam deposition system with mass separator Ion implanter schematic.svg
Ion beam deposition system with mass separator

Gas flows through the ion source between the anode and the cathode. A positive voltage is applied to the anode. This voltage, combined with the high magnetic field between the tips of the internal and external cathodes allow a plasma to start. Ions from the plasma are repelled by the anode's electric field. This creates an ion beam. [83]

Surface modification

See also

Related Research Articles

<span class="mw-page-title-main">Mass spectrometry</span> Analytical technique based on determining mass to charge ratio of ions

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">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">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.

<span class="mw-page-title-main">Liquid chromatography–mass spectrometry</span> Analytical chemistry technique

Liquid chromatography–mass spectrometry (LC–MS) is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography with the mass analysis capabilities of mass spectrometry (MS). Coupled chromatography – MS systems are popular in chemical analysis because the individual capabilities of each technique are enhanced synergistically. While liquid chromatography separates mixtures with multiple components, mass spectrometry provides spectral information that may help to identify each separated component. MS is not only sensitive, but provides selective detection, relieving the need for complete chromatographic separation. LC–MS is also appropriate for metabolomics because of its good coverage of a wide range of chemicals. This tandem technique can be used to analyze biochemical, organic, and inorganic compounds commonly found in complex samples of environmental and biological origin. Therefore, LC–MS may be applied in a wide range of sectors including biotechnology, environment monitoring, food processing, and pharmaceutical, agrochemical, and cosmetic industries. Since the early 2000s, LC–MS has also begun to be used in clinical applications.

<span class="mw-page-title-main">Fast atom bombardment</span>

Fast atom bombardment (FAB) is an ionization technique used in mass spectrometry in which a beam of high energy atoms strikes a surface to create ions. It was developed by Michael Barber at the University of Manchester in 1980. When a beam of high energy ions is used instead of atoms, the method is known as liquid secondary ion mass spectrometry (LSIMS). In FAB and LSIMS, the material to be analyzed is mixed with a non-volatile chemical protection environment, called a matrix, and is bombarded under vacuum with a high energy atomic beam. The atoms are typically from an inert gas such as argon or xenon. Common matrices include glycerol, thioglycerol, 3-nitrobenzyl alcohol (3-NBA), 18-crown-6 ether, 2-nitrophenyloctyl ether, sulfolane, diethanolamine, and triethanolamine. This technique is similar to secondary ion mass spectrometry and plasma desorption mass spectrometry.

<span class="mw-page-title-main">Atmospheric-pressure chemical ionization</span> Ionization method

Atmospheric pressure chemical ionization (APCI) is an ionization method used in mass spectrometry which utilizes gas-phase ion-molecule reactions at atmospheric pressure (105 Pa), commonly coupled with high-performance liquid chromatography (HPLC). APCI is a soft ionization method similar to chemical ionization where primary ions are produced on a solvent spray. The main usage of APCI is for polar and relatively less polar thermally stable compounds with molecular weight less than 1500 Da. The application of APCI with HPLC has gained a large popularity in trace analysis detection such as steroids, pesticides and also in pharmacology for drug metabolites.

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

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 and 22Ne. Mass spectrometers were used in the Manhattan Project for the separation of isotopes of uranium necessary to create the atomic bomb.

In mass spectrometry, direct analysis in real time (DART) is an ion source that produces electronically or vibronically excited-state species from gases such as helium, argon, or nitrogen that ionize atmospheric molecules or dopant molecules. The ions generated from atmospheric or dopant molecules undergo ion-molecule reactions with the sample molecules to produce analyte ions. Analytes with low ionization energy may be ionized directly. The DART ionization process can produce positive or negative ions depending on the potential applied to the exit electrode.

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

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> Ambient ionization technique

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> Ambient ionization technique

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">Surface-assisted laser desorption/ionization</span>

Surface-assisted laser desorption/ionization (SALDI) is a soft laser desorption technique used for mass spectrometry analysis of biomolecules, polymers, and small organic molecules. In its first embodiment Koichi Tanaka used a cobalt/glycerol liquid matrix and subsequent applications included a graphite/glycerol liquid matrix as well as a solid surface of porous silicon. The porous silicon represents the first matrix-free SALDI surface analysis allowing for facile detection of intact molecular ions, these porous silicon surfaces also facilitated the analysis of small molecules at the yoctomole level. At present laser desorption/ionization methods using other inorganic matrices such as nanomaterials are often regarded as SALDI variants. As an example, silicon nanowires as well as Titania nanotube arrays (NTA) have been used as substrates to detect small molecules. SALDI is used to detect proteins and protein-protein complexes. A related method named "ambient SALDI" - which is a combination of conventional SALDI with ambient mass spectrometry incorporating the direct analysis real time (DART) ion source has also been demonstrated. SALDI is considered one of the most important techniques in MS and has many applications.

<span class="mw-page-title-main">Atmospheric-pressure photoionization</span> Soft ionization method

Atmospheric pressure photoionization (APPI) is a soft ionization method used in mass spectrometry (MS) usually coupled to liquid chromatography (LC). Molecules are ionized using a vacuum ultraviolet (VUV) light source operating at atmospheric pressure, either by direct absorption followed by electron ejection or through ionization of a dopant molecule that leads to chemical ionization of target molecules. The sample is usually a solvent spray that is vaporized by nebulization and heat. The benefit of APPI is that it ionizes molecules across a broad range of polarity and is particularly useful for ionization of low polarity molecules for which other popular ionization methods such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are less suitable. It is also less prone to ion suppression and matrix effects compared to ESI and APCI and typically has a wide linear dynamic range. The application of APPI with LC/MS is commonly used for analysis of petroleum compounds, pesticides, steroids, and drug metabolites lacking polar functional groups and is being extensively deployed for ambient ionization particularly for explosives detection in security applications.

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

In mass spectrometry, matrix-assisted ionization is a low fragmentation (soft) ionization technique which involves the transfer of particles of the analyte and matrix sample from atmospheric pressure (AP) to the heated inlet tube connecting the AP region to the vacuum of the mass analyzer.

<span class="mw-page-title-main">Laser diode thermal desorption</span>

Laser diode thermal desorption (LDTD) is an ionization technique that is coupled to mass spectrometry to analyze samples with atmospheric pressure chemical ionization (APCI). It uses a laser to thermally desorb analytes that are deposited on a stainless steel sheet sample holder, called LazWell. The coupling of LDTD and APCI is considered to be a soft-ionization technique. With LDTD-APCI, it is possible to analyze samples in forensics, pharmaceuticals, environment, food and clinical studies. LDTD is suitable for small molecules between 0 and 1200 Da and some peptides such as cyclosporine.

Soft Ionization by Chemical Reaction in Transfer is a method for ionizing small organic compounds at ambient atmospheric pressure. It is used for ion generation in mass spectrometers (MS).

References

  1. 1 2 Bernhard Wolf (31 August 1995). Handbook of Ion Sources. CRC Press. ISBN   978-0-8493-2502-1.
  2. ↑ Ian G. Brown (6 March 2006). The Physics and Technology of Ion Sources. John Wiley & Sons. ISBN   978-3-527-60454-8.
  3. ↑ Heinrich Beyer; Heinrich F. Beyer; H.-Jürgen Kluge; H.-J. Kluge; Vi͡acheslav Petrovich Shevelʹko (14 August 1997). X-Ray Radiation of Highly Charged Ions. Springer Science & Business Media. ISBN   978-3-540-63185-9.
  4. ↑ Donald F. Hunt; Frank W. Crow (1978), "Electron capture negative ion chemical ionization mass spectrometry", Analytical Chemistry, 50 (13): 1781–1784, doi:10.1021/ac50035a017
  5. ↑ IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) " electron capture detector (in gas chromatography) ". doi : 10.1351/goldbook.E01981
  6. ↑ Munson, M. S. B.; Field, F. H. (1966). "Chemical Ionization Mass Spectrometry. I. General Introduction". Journal of the American Chemical Society. 88 (12): 2621–2630. Bibcode:1966JAChS..88.2621M. doi:10.1021/ja00964a001.
  7. ↑ de Hoffmann, Edmond; Vincent Stroobant (2003). Mass Spectrometry: Principles and Applications (Second ed.). Toronto: John Wiley & Sons, Ltd. p. 14. ISBN   978-0-471-48566-7.
  8. ↑ IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) " charge-exchange ionization ". doi : 10.1351/goldbook.C00989
  9. ↑ IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) " chemi-ionization ". doi : 10.1351/goldbook.C01044 C01044
  10. ↑ Klucharev, A. N. (1993), "Chemi-ionization processes", Physics-Uspekhi, 36 (6): 486–512, Bibcode:1993PhyU...36..486K, doi:10.1070/PU1993v036n06ABEH002162
  11. ↑ IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) " associative ionization ". doi : 10.1351/goldbook.A00475
  12. ↑
  13. ↑ Cohen, James S. (1976). "Multistate curve-crossing model for scattering: Associative ionization and excitation transfer in helium". Physical Review A. 13 (1): 99–114. Bibcode:1976PhRvA..13...99C. doi:10.1103/PhysRevA.13.99.
  14. ↑ Arango CA, Shapiro M, Brumer P (2006). "Cold atomic collisions: coherent control of penning and associative ionization". Phys. Rev. Lett. 97 (19): 193202. arXiv: physics/0610131 . Bibcode:2006PhRvL..97s3202A. doi:10.1103/PhysRevLett.97.193202. PMID   17155624. S2CID   1480148.
  15. ↑ Hiraoka K, Furuya H, Kambara S, Suzuki S, Hashimoto Y, Takamizawa A (2006). "Atmospheric-pressure Penning ionization of aliphatic hydrocarbons". Rapid Commun. Mass Spectrom. 20 (21): 3213–22. Bibcode:2006RCMS...20.3213H. doi:10.1002/rcm.2706. PMID   17016831.
  16. ↑ Penning, F. M. Die Naturwissenschaften, 1927, 15, 818. Über Ionisation durch metastabile Atome.
  17. ↑ IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) " Penning gas mixture ". doi : 10.1351/goldbook.P04476
  18. ↑ Selvin, P. Christopher; Fujii, Toshihiro (2001). "Lithium ion attachment mass spectrometry: Instrumentation and features". Review of Scientific Instruments. 72 (5): 2248. Bibcode:2001RScI...72.2248S. doi:10.1063/1.1362439.
  19. ↑ Broekaert, J. A. C. (January 1993). "Inductively Coupled Plasmas in Analytical Atomic Spectrometry Eds.: A. Montaser and D. W. Golightly VCH, Weinheim, 2nd Edition. 1992, ISBN 3-527-28339-0, 984 pp., Hardcover, DM 296,—". Acta Hydrochimica et Hydrobiologica. 21 (6): 327–328. doi:10.1002/aheh.19930210610.
  20. ↑ Okamoto, Yukio (1994). "High-sensitivity microwave-induced plasma mass spectrometry for trace element analysis". Journal of Analytical Atomic Spectrometry. 9 (7): 745. doi:10.1039/ja9940900745. ISSN   0267-9477.
  21. ↑ Douglas, D. J.; French, J. B. (1981). "Elemental analysis with a microwave-induced plasma/quadrupole mass spectrometer system". Analytical Chemistry. 53 (1): 37–41. doi:10.1021/ac00224a011. ISSN   0003-2700.
  22. ↑ Lejeune, C. (1974). "Theoretical and experimental study of the duoplasmatron ion source". Nuclear Instruments and Methods. 116 (3): 417–428. Bibcode:1974NucIM.116..417L. doi:10.1016/0029-554X(74)90821-0. ISSN   0029-554X.
  23. ↑ Aberth, William; Peterson, James R. (1967). "Characteristics of a Low Energy Duoplasmatron Negative Ion Source". Review of Scientific Instruments. 38 (6): 745. Bibcode:1967RScI...38..745A. doi:10.1063/1.1720882. ISSN   0034-6748.
  24. ↑ Coath, C. D.; Long, J. V. P. (1995). "A high-brightness duoplasmatron ion source for microprobe secondary-ion mass spectrometry". Review of Scientific Instruments. 66 (2): 1018. Bibcode:1995RScI...66.1018C. doi: 10.1063/1.1146038 . ISSN   0034-6748.
  25. ↑ Christine M. Mahoney (9 April 2013). Cluster Secondary Ion Mass Spectrometry: Principles and Applications. John Wiley & Sons. pp. 65–. ISBN   978-1-118-58925-0.
  26. ↑ Stanley Humphries (25 July 2013). Charged Particle Beams. Dover Publications. pp. 309–. ISBN   978-0-486-31585-0.
  27. ↑ Ferguson, E. E.; Fehsenfeld, F. C.; Schmeltekopf, A. L. (1969). "Ion-Molecule Reaction Rates Measured in a Discharge Afterglow". Chemical Reactions in Electrical Discharges. Advances in Chemistry. Vol. 80. pp. 83–91. doi:10.1021/ba-1969-0080.ch006. ISBN   978-0-8412-0081-4. ISSN   0065-2393.
  28. ↑ Ferguson, Eldon E. (1992). "A Personal history of the early development of the flowing afterglow technique for ion-molecule reaction studies". Journal of the American Society for Mass Spectrometry (Submitted manuscript). 3 (5): 479–486. Bibcode:1992JASMS...3..479F. doi: 10.1016/1044-0305(92)85024-E . ISSN   1044-0305. PMID   24234490.
  29. ↑ Bierbaum, Veronica M. (2014). "Go with the flow: Fifty years of innovation and ion chemistry using the flowing afterglow". International Journal of Mass Spectrometry. 377: 456–466. Bibcode:2015IJMSp.377..456B. doi:10.1016/j.ijms.2014.07.021. ISSN   1387-3806.
  30. ↑ Smith, David; Španěl, Patrik (2005). "Selected ion flow tube mass spectrometry (SIFT-MS) for on-line trace gas analysis". Mass Spectrometry Reviews. 24 (5): 661–700. Bibcode:2005MSRv...24..661S. doi:10.1002/mas.20033. ISSN   0277-7037. PMID   15495143.
  31. ↑ Dhooghe, Frederik; Vansintjan, Robbe; Schoon, Niels; Amelynck, Crist (2012-08-30). "Studies in search of selective detection of isomeric biogenic hexen-1-ols and hexanal by flowing afterglow tandem mass spectrometry using [H3O]+ and [NO]+ reagent ions". Rapid Communications in Mass Spectrometry. 26 (16): 1868–1874. doi:10.1002/rcm.6294. ISSN   1097-0231. PMID   22777789.
  32. ↑ H. E. Beske; A. Hurrle; K. P. Jochum (1981). "Part I. Principles of spark source mass spectrometry (SSMS)". Fresenius' Journal of Analytical Chemistry . 309 (4): 258–261. doi:10.1007/BF00488596. S2CID   92433014.
  33. ↑ IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) " photoionization ". doi : 10.1351/goldbook.P04620
  34. ↑ Beckey, H.D. (1969). "Field ionization mass spectrometry". Research/Development. 20 (11): 26.
  35. ↑ Williams, Dudley H.; Findeis, A. Frederick; Naylor, Stephen; Gibson, Bradford W. (1987). "Aspects of the production of FAB and SIMS mass spectra". Journal of the American Chemical Society. 109 (7): 1980–1986. Bibcode:1987JAChS.109.1980W. doi:10.1021/ja00241a013. ISSN   0002-7863.
  36. ↑ Morris HR, Panico M, Barber M, Bordoli RS, Sedgwick RD, Tyler A (1981). "Fast atom bombardment: a new mass spectrometric method for peptide sequence analysis". Biochem. Biophys. Res. Commun. 101 (2): 623–31. doi:10.1016/0006-291X(81)91304-8. PMID   7306100.
  37. ↑ Macfarlane, R.; Torgerson, D. (1976). "Californium-252 plasma desorption mass spectroscopy". Science. 191 (4230): 920–925. Bibcode:1976Sci...191..920M. doi:10.1126/science.1251202. ISSN   0036-8075. PMID   1251202.
  38. ↑ Hilf, E.R. (1993). "Approaches to plasma desorption mass spectrometry by some theoretical physics concepts". International Journal of Mass Spectrometry and Ion Processes. 126: 25–36. Bibcode:1993IJMSI.126...25H. doi:10.1016/0168-1176(93)80067-O. ISSN   0168-1176.
  39. 1 2 Sunner, Jan.; Dratz, Edward.; Chen, Yu-Chie. (1995). "Graphite surface-assisted laser desorption/ionization time-of-flight mass spectrometry of peptides and proteins from liquid solutions". Analytical Chemistry. 67 (23): 4335–4342. doi:10.1021/ac00119a021. ISSN   0003-2700. PMID   8633776.
  40. ↑ Dattelbaum, Andrew M; Iyer, Srinivas (2006). "Surface-assisted laser desorption/ionization mass spectrometry". Expert Review of Proteomics (Submitted manuscript). 3 (1): 153–161. doi:10.1586/14789450.3.1.153. ISSN   1478-9450. PMID   16445359. S2CID   39538990.
  41. ↑ Zhang, Jialing; Li, Ze; Zhang, Chengsen; Feng, Baosheng; Zhou, Zhigui; Bai, Yu; Liu, Huwei (2012). "Graphite-Coated Paper as Substrate for High Sensitivity Analysis in Ambient Surface-Assisted Laser Desorption/Ionization Mass Spectrometry". Analytical Chemistry. 84 (7): 3296–3301. doi:10.1021/ac300002g. ISSN   0003-2700. PMID   22380704.
  42. ↑ Tang N, Tornatore P, Weinberger SR (2004). "Current developments in SELDI affinity technology". Mass Spectrometry Reviews. 23 (1): 34–44. Bibcode:2004MSRv...23...34T. doi:10.1002/mas.10066. PMID   14625891.
  43. ↑ Buriak, Jillian M.; Wei, Jing; Siuzdak, Gary (1999). "Desorption-ionization mass spectrometry on porous silicon". Nature. 399 (6733): 243–246. Bibcode:1999Natur.399..243W. doi:10.1038/20400. ISSN   0028-0836. PMID   10353246. S2CID   4314372.
  44. ↑ Duncan, Michael A. (2012). "Invited Review Article: Laser vaporization cluster sources". Review of Scientific Instruments. 83 (4): 041101–041101–19. Bibcode:2012RScI...83d1101D. doi:10.1063/1.3697599. ISSN   0034-6748. PMID   22559508.
  45. ↑ Laser Ablation and Desorption. Academic Press. 10 December 1997. pp. 628–. ISBN   978-0-08-086020-6.
  46. ↑ Smalley, Richard (1997). "Discovering the fullerenes". Reviews of Modern Physics. 69 (3): 723–730. Bibcode:1997RvMP...69..723S. doi:10.1103/RevModPhys.69.723. ISSN   0034-6861.
  47. ↑ Roy L. Johnston (25 April 2002). Atomic and Molecular Clusters. CRC Press. pp. 150–. ISBN   978-1-4200-5577-1.
  48. ↑ Carson, P; Neubauer, K; Johnston, M; Wexler, A (1995). "On-line chemical analysis of aerosols by rapid single-particle mass spectrometry". Journal of Aerosol Science. 26 (4): 535–545. Bibcode:1995JAerS..26..535C. doi:10.1016/0021-8502(94)00133-J.
  49. ↑ Guazzotti, S; Coffee, K; Prather, K (2000). "Real time monitoring of size-resolved single particle chemistry during INDOEX-IFP 99". Journal of Aerosol Science. 31: 182–183. Bibcode:2000JAerS..31..182G. doi:10.1016/S0021-8502(00)90189-7.
  50. ↑ Chhabil Dass (11 May 2007). Fundamentals of Contemporary Mass Spectrometry. John Wiley & Sons. pp. 45–57. ISBN   978-0-470-11848-1.
  51. ↑ Pagnotti VS, Chubatyi ND, McEwen CN (2011). "Solvent Assisted Inlet Ionization: an Ultrasensitive New Liquid Introduction Ionization Method for Mass Spectrometry". Anal. Chem. 83 (11): 3981–3985. doi:10.1021/ac200556z. PMID   21528896.
  52. ↑ Pagnotti VS, Chakrabarty S, Harron AF, McEwen CN (2012). "Increasing the Sensitivity of Liquid Introduction Mass Spectrometry by Combining Electrospray Ionization and Solvent Assisted Inlet Ionization". Anal. Chem. 84 (15): 6828–6832. doi:10.1021/ac3014115. PMID   22742705.
  53. ↑ Trimpin S, Wang B, Lietz CB, Marshall DD, Richards AL, Inutan ED. "New Ionization Processes and Applications for Use in Mass Spectrometry". Rev. Biochem. Mol. Biol. 2013. 5: 409–429.
  54. ↑ Prakash C, Shaffer CL, Nedderman A (2007). "Analytical strategies for identifying drug metabolites". Mass Spectrometry Reviews. 26 (3): 340–69. Bibcode:2007MSRv...26..340P. doi:10.1002/mas.20128. PMID   17405144.
  55. ↑ Zaikin VG, Halket JM (2006). "Derivatization in mass spectrometry--8. Soft ionization mass spectrometry of small molecules". European Journal of Mass Spectrometry. 12 (2): 79–115. doi:10.1255/ejms.798. PMID   16723751. S2CID   34838846.
  56. ↑ "Atmospheric pressure ionization in mass spectrometry". IUPAC Compendium of Chemical Terminology. 2009. doi:10.1351/goldbook.A00492. ISBN   978-0-9678550-9-7.
  57. ↑ Blakley, C. R.; Carmody, J. J.; Vestal, M. L. (1980). "Liquid Chromatograph-Mass Spectrometer for Analysis of Nonvolatile Samples". Analytical Chemistry. 1980 (52): 1636–1641. doi:10.1021/ac50061a025.
  58. ↑ Fenn, J. B.; Mann, M.; Meng, C. K.; Wong, S. F.; Whitehouse, C. M. (1990). "Electrospray Ionization-Principles and Practice". Mass Spectrometry Reviews . 9 (1): 37–70. Bibcode:1990MSRv....9...37F. doi:10.1002/mas.1280090103.
  59. ↑ Hiraoka K.; Nishidate K.; Mori K.; Asakawa D.; Suzuki S. (2007). "Development of probe electrospray using a solid needle". Rapid Communications in Mass Spectrometry . 21 (18): 3139–3144. Bibcode:2007RCMS...21.3139H. doi:10.1002/rcm.3201. PMID   17708527.
  60. ↑ Hsieh, Cheng-Huan; Chang, Chia-Hsien; Urban, Pawel L.; Chen, Yu-Chie (2011). "Capillary Action-Supported Contactless Atmospheric Pressure Ionization for the Combined Sampling and Mass Spectrometric Analysis of Biomolecules". Analytical Chemistry. 83 (8): 2866–2869. doi:10.1021/ac200479s. ISSN   0003-2700. PMID   21446703.
  61. ↑ Hirabayashi A, Sakairi M, Koizumi H (1995). "Sonic spray mass spectrometry". Anal. Chem. 67 (17): 2878–82. doi:10.1021/ac00113a023. PMID   8779414.
  62. ↑ Chen, Tsung-Yi; Lin, Jia-Yi; Chen, Jen-Yi; Chen, Yu-Chie (2011-11-22). "Ultrasonication-assisted spray ionization mass spectrometry for the analysis of biomolecules in solution". Journal of the American Society for Mass Spectrometry. 21 (9): 1547–1553. Bibcode:2010JASMS..21.1547C. doi: 10.1016/j.jasms.2010.04.021 . ISSN   1044-0305. PMID   20547459.
  63. ↑ Arinobu T, Hattori H, Seno H, Ishii A, Suzuki O (2002). "Comparison of SSI with APCI as an interface of HPLC-mass spectrometry for analysis of a drug and its metabolites". J. Am. Soc. Mass Spectrom. 13 (3): 204–208. Bibcode:2002JASMS..13..204A. doi: 10.1016/S1044-0305(01)00359-2 . PMID   11908800.
  64. ↑ Dams R, Benijts T, Günther W, Lambert W, De Leenheer A (2002). "Sonic spray ionization technology: performance study and application to a LC/MS analysis on a monolithic silica column for heroin impurity profiling". Anal. Chem. 74 (13): 3206–3212. doi:10.1021/ac0112824. PMID   12141684.
  65. ↑ Huang M, Hirabayashi A, Okumura A, Hirabayashi Y (2001). "Matrix effect on the analysis of oligonucleotides by using a mass spectrometer with a sonic spray ionization source". Anal Sci. 17 (10): 1179–1182. doi: 10.2116/analsci.17.1179 . PMID   11990592.
  66. ↑ Huang M, Hirabayashi A (2002). "Multi-charged oligonucleotide ion formation in sonic spray ionization". Anal Sci. 18 (4): 385–390. doi: 10.2116/analsci.18.385 . PMID   11999509.
  67. ↑ Haddad R, Sparrapan R, Eberlin MN (2006). "Desorption sonic spray ionization for (high) voltage-free ambient mass spectrometry". Rapid Commun. Mass Spectrom. 20 (19): 2901–2905. Bibcode:2006RCMS...20.2901H. doi:10.1002/rcm.2680. PMID   16941547.
  68. ↑ Haddad R, Milagre HM, Catharino RR, Eberlin MN (2008). "Easy Ambient Sonic-Spray Ionization Mass Spectrometry Combined with Thin-Layer Chromatography". Anal. Chem. 80 (8): 2744–2750. doi:10.1021/ac702216q. PMID   18331004.
  69. ↑ Chen, Tsung-Yi; Lin, Jia-Yi; Chen, Jen-Yi; Chen, Yu-Chie (2010). "Ultrasonication-assisted spray ionization mass spectrometry for the analysis of biomolecules in solution". Journal of the American Society for Mass Spectrometry. 21 (9): 1547–1553. Bibcode:2010JASMS..21.1547C. doi: 10.1016/j.jasms.2010.04.021 . PMID   20547459.
  70. ↑ Chen, Tsung-Yi; Chao, Chin-Sheng; Mong, Kwok-Kong Tony; Chen, Yu-Chie (4 November 2010). "Ultrasonication-assisted spray ionization mass spectrometry for on-line monitoring of organic reactions". Chemical Communications. 46 (44): 8347–9. doi:10.1039/C0CC02629H. PMID   20957254 . Retrieved 4 November 2011.
  71. ↑ Alton, G. D. (1988). "Characterization of a cesium surface ionization source with a porous tungsten ionizer. I". Review of Scientific Instruments (Submitted manuscript). 59 (7): 1039. Bibcode:1988RScI...59.1039A. doi:10.1063/1.1139776. ISSN   0034-6748.
  72. ↑ "A Negative-Surface Ionization for Generation of Halogen Radioactive Ion Beams" (PDF). Archived from the original (PDF) on 2004-12-18. Retrieved 2014-01-20.
  73. ↑ Cooks, R. Graham; Ouyang, Zheng; Takats, Zoltan; Wiseman, Justin M. (2006). "Ambient Mass Spectrometry". Science. 311 (5767): 1566–70. Bibcode:2006Sci...311.1566C. doi:10.1126/science.1119426. PMID   16543450. S2CID   98131681.
  74. 1 2 Monge, María Eugenia; Harris, Glenn A.; Dwivedi, Prabha; Fernández, Facundo M. (2013). "Mass Spectrometry: Recent Advances in Direct Open Air Surface Sampling/Ionization". Chemical Reviews. 113 (4): 2269–2308. doi:10.1021/cr300309q. ISSN   0009-2665. PMID   23301684.
  75. ↑ Huang, Min-Zong; Yuan, Cheng-Hui; Cheng, Sy-Chyi; Cho, Yi-Tzu; Shiea, Jentaie (2010). "Ambient Ionization Mass Spectrometry". Annual Review of Analytical Chemistry. 3 (1): 43–65. Bibcode:2010ARAC....3...43H. doi:10.1146/annurev.anchem.111808.073702. ISSN   1936-1327. PMID   20636033.
  76. ↑ Badu-Tawiah, Abraham K.; Eberlin, Livia S.; Ouyang, Zheng; Cooks, R. Graham (2013). "Chemical Aspects of the Extractive Methods of Ambient Ionization Mass Spectrometry". Annual Review of Physical Chemistry. 64 (1): 481–505. Bibcode:2013ARPC...64..481B. doi:10.1146/annurev-physchem-040412-110026. ISSN   0066-426X. PMID   23331308.
  77. ↑ Takáts Z, Wiseman JM, Cooks RG (2005). "Ambient mass spectrometry using desorption electrospray ionization (DESI): instrumentation, mechanisms and applications in forensics, chemistry, and biology". Journal of Mass Spectrometry. 40 (10): 1261–75. Bibcode:2005JMSp...40.1261T. doi: 10.1002/jms.922 . PMID   16237663.
  78. ↑ McEwen CN, McKay RG, Larsen BS (2005). "Analysis of Solids, Liquids, and Biological Tissues Using Solids Probe Introduction at Atmospheric Pressure on Commercial LC/MS Instruments". Anal. Chem. 77 (23): 7826–7831. doi:10.1021/ac051470k. PMID   16316194.
  79. ↑ Shiea J, Huang MZ, Hsu HJ, Lee CY, Yuan CH, Beech I, Sunner J (2005). "Electrospray-assisted laser desorption/ionization mass spectrometry for direct ambient analysis of solids". Rapid Commun. Mass Spectrom. 19 (24): 3701–4. Bibcode:2005RCMS...19.3701S. doi:10.1002/rcm.2243. PMID   16299699.
  80. ↑ Peng, Ivory X.; Ogorzalek Loo, Rachel R.; Margalith, Eli; Little, Mark W.; Loo, Joseph A. (2010). "Electrospray-assisted laser desorption ionization mass spectrometry (ELDI-MS) with an infrared laser for characterizing peptides and proteins". The Analyst. 135 (4): 767–72. Bibcode:2010Ana...135..767P. doi:10.1039/b923303b. ISSN   0003-2654. PMC   3006438 . PMID   20349541.
  81. ↑ Sampson, JS; Hawkridge, AM; Muddiman, DC (2006). "Generation and detection of multiply charged peptides and proteins by matrix-assisted laser desorption electrospray ionization (MALDESI) Fourier transform ion cyclotron resonance mass spectrometry". J. Am. Soc. Mass Spectrom. 17 (12): 1712–6. Bibcode:2006JASMS..17.1712S. doi: 10.1016/j.jasms.2006.08.003 . PMID   16952462.
  82. ↑ 35 years of H- ions at Fermilab (PDF). Fermilab. p. 12. Retrieved 12 August 2015.
  83. ↑ Cooks, R. G; Ouyang, Z; Takats, Z; Wiseman, J. M (2006). "Ion Beam Sources" (PDF). Science. 311 (5767): 1566–70. Bibcode:2006Sci...311.1566C. doi:10.1126/science.1119426. PMID   16543450. S2CID   98131681. Archived from the original (PDF) on 2006-10-18. Retrieved 2006-12-14.
  84. ↑ "Ion Beam Source Technology". Advanced Energy. Archived from the original on October 18, 2006. Retrieved 2006-12-14.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.