Mass spectrometry Mass spectrometry Atmospheric pressure chemical ionization (APCI) is an ionization source used in mass spectrometry. It is a form of chemical ionization which takes place at atmopheric pressure. This ionization technique allows for the high flow rates typical of standard bore HPLC to be used directly, often without diverting the larger fraction of volume to waste. Typically the mobile phase containing eluting analyte is heated 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. Often APCI can be performed in a modified ESI source. ...more on Wikipedia about "Atmospheric pressure chemical ionization"
In mass spectrometry blackbody infrared radiative dissociation (BIRD) is a method for fragmenting gas phase ions for tandem mass spectrometric analysis (structural elucidation). BIRD uses the light from black body radiation to thermally (vibrationally) excite the ions until a bond breaks. This is very similar to infrared multiphoton dissociation with the exception of the source of radiation. This technique is most often studied in Fourier transform ion cyclotron resonance mass spectrometry. ...more on Wikipedia about "Blackbody infrared radiative dissociation"
A Calutron was a mass spectrometer used for separating the isotopes of uranium developed by Ernest O. Lawrence during the Manhattan Project. 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. 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. ...more on Wikipedia about "Calutron"
Chemical ionization (CI) is an ionization technique used in mass spectrometry. ...more on Wikipedia about "Chemical ionization"
In mass spectrometry, collision-induced dissociation (CID), referred to by some as collisionally activated dissociation (CAD), is a mechanism by which to fragment molecular ions in the gas phase. The molecular ions are usually accelerated by some electrical potential to high kinetic energy in the vacuum of a mass spectrometer and then allowed to collide with neutral gas molecules (often helium, nitrogen or argon). In the collision some of the kinetic energy is converted into internal energy which results in bond breakage and the fragmentation of the molecular ion into smaller fragments. These fragment ions can then be analyzed by a mass spectrometer. ...more on Wikipedia about "Collision-induced dissociation"
The Einzel lens is used in Ion optics to focus ions in flight and is accomplished through manipulation of the electric field in the path of the ions. It consists of three or more sets of rectangular prisms in series along an axis. As the prisms consist of four sides, each pair of facing plates manipulate the electric field to deflect ions as they pass through. ...more on Wikipedia about "Einzel lens"
In mass spectrometry, electron capture dissociation (ECD) is a method of fragmenting gas phase ions for tandem mass spectrometric analysis (structural elucidation). ECD involves the introduction of low energy electrons to trapped gas phase ions. ECD produces significantly different types of fragment ions than other fragmentation methods such as collision-induced dissociation and infrared multiphoton dissociation. These other methods introduce internal vibrational energy in some way or another while ECD does not. The unique (and complementary) fragments observed and the ability to fragment whole macromolecules effectively has been promising. The low efficiencies and other experimental difficulties have prevented wide spread use. ECD is primarily used in Fourier transform ion cyclotron resonance mass spectrometry. ...more on Wikipedia about "Electron capture dissociation"
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Electron ionization (EI, formerly known as electron impact) is an ionization technique widely used in mass spectrometry, particularly for organic molecules. ...more on Wikipedia about "Electron ionization"
An electron multiplier (continuous dynode electron multiplier) multiplies charge. Ions can, when bombarded on metal (or PbO coated surface) induce emission of electrons. If an electric potential is applied from one metal plate to the other, the emitted electrons will accelerate to the next metal plate and induce emission of more electrons. These electron can be accelerated to another metal plate and the whole process will be repeated but with more and more electrons. Therefore, another name for electron multipliers is avalanching ion detector. 12 stages of acceleration will usually give a gain in current of 10 million. ...more on Wikipedia about "Electron multiplier"
Electrospray ionization (ESI) is a technique used in mass spectrometry to produce ions. It is especially useful in producing ions from macromolecules because it overcomes the propensity of these molecules to fragment when ionized. The invention of electrospray ionization was rewarded with the attribution of the Nobel Prize in Chemistry to John Fenn in 2002. ...more on Wikipedia about "Electrospray ionization"
A faraday cup is a metal (conductive) cup meant to recatch secondary particles. (See Black body#Details). When a beam or packet of ions hits the metal it will be charged while the ions are neutralized. The metal can then be discharged to measure a small current equivalent to the number of discharged ions. Essentially the faraday cup is part of a circuit where ions in the gas phase act as charge carriers during part of the circuit and the faraday cup is the interface to the solid phase where electrons act as the charge carriers (as in most circuits). By measuring the electrical current (the number of electrons flowing through the circuit per second) on the metal part of the circuit the number of charges being carried by the ions in the gas phase part of the circuit can be determined. ...more on Wikipedia about "Faraday cup"
Fast atom bombardment (FAB) is an ionization technique used in mass spectrometry in which an analyte and liquid matrix mixture is bombarded by a ~8KeV particle beam of usually inert gas such as argon or xenon. Common matricies include glycerol and 3-nitrobenzyl alcohol (3-NBA). This technique is very closely related to (if not part of) secondary ion mass spectrometry. FAB is a relatively soft ionization technique and produces primarily protonated molecules denoted as [M+H]+ and deprotonated molecules such as [M-H]-. The nature of its ionization products places it close to electrospray and MALDI. ...more on Wikipedia about "Fast atom bombardment"
Flowing afterglow mass spectrometry, FA-MS, is a sensitive and quantitative mass spectrometry analytical approach that offers a route to on-line, real-time deuterium abundance measurements in water vapour in breath and above aqueous liquids, including urine and serum. This method involves the production and flow of thermalised hydrated hydronium cluster ions in inert helium or argon carrier gas along a flow tube following the introduction of a humid air sample. These ions react in multiple collisions with water molecules, their isotopic compositions reach equilibrium and the relative magnitudes of their isotopomers are measured by a quadrupole mass spectrometer located downstream. ...more on Wikipedia about "Flowing afterglow mass spectrometry"
Fourier transform ion cyclotron resonance mass spectrometry, also known as Fourier transform mass spectrometry, is a type of mass analyzer (or mass spectrometer) for determining the mass to charge ratio (m/z) of ions based on the cyclotron frequency of the ions in a fixed magnetic field. The ions are trapped in a Penning trap (a magnetic field with electric trapping plates) where they are excited to a larger cyclotron radius by an oscillating electric field perpendicular to the magnetic field. The excitation also results in the ions moving in phase (in a packet). The signal is detected as an image current on a pair of plates which the packet of ions passes close to as they cyclotron. The resulting signal is called a free induction decay (fid), transient or interferogram that consists of a superposition of sine waves. The useful signal is extracted from this data by performing a Fourier transform to give a mass spectrum. Specifically a fast Fourier transform (FFT) is usually used to transform the discrete fid data. ...more on Wikipedia about "Fourier transform ion cyclotron resonance"
Gas chromatography-mass spectrometry (GC-MS) is a method that combines the features of gas-liquid chromatography and mass spectrometry to identify different substances within a test sample. Applications of GC-MS include drug detection, fire investigation, environmental analysis, and explosives investigation. GC-MS can also be used in airport security to detect substances in luggage or on human beings. Additionally, it can identify trace elements in materials that were previously thought to have disintegrated beyond identification. ...more on Wikipedia about "Gas chromatography-mass spectrometry"
A Helium mass spectrometer (often called a leak detector) or sniffer, is a scientific instrument, used to detect very small leaks, typically using a vacuum and injecting helium around a chamber or cavity. ...more on Wikipedia about "Helium mass spectrometer"
ICP-MS (Inductively Coupled Plasma Mass Spectrometry) is a type of mass spectrometry that is highly sensitive and capable of analysis of a range of metals and several non-metals at below one part in 1012. It is based on coupling together an inductively coupled plasma as a method of producing ions ( ionization) with a mass spectrometer as a method of identifying and detecting the ions. ...more on Wikipedia about "ICP-MS"
Infrared multiphoton dissociation (IRMPD) is a technique used in mass spectrometry to fragment molecules in the gas phase usually for structural anaylsis of the original (parent) molecule. An infrared laser is directed through a window into the vacuum of the mass spectrometer where the ions are. The mechanism of fragmentation involves the absorption by a given ion of multiple infrared photons. The parent ion becomes excited into more energetic vibrational states until a bond(s) is broken resulting in gas phase fragments of the parent ion. ...more on Wikipedia about "Infrared multiphoton dissociation"
An ion mobility spectrometer (IMS) is a spectrometer capable of detection and identification of very low concentrations of chemicals. It can be miniaturized and it can operate at atmospheric pressure. ...more on Wikipedia about "Ion mobility spectrometer"
In mass spectrometry, an ion source is a piece of equipment used to ionize analyte molecules and, if necessary, free them from the solid or liquid phase. Once the analyte ions are free to move electric fields will direct them into the mass analyzer. ...more on Wikipedia about "Ion source"
An ion trap is a combination of electric or magnetic fields that captures ions in a region of a vacuum system or tube. Two notable types of ion traps are the Penning trap and the Paul trap. ...more on Wikipedia about "Ion trap" www.shortopedia.com Is Good For You.
Liquid chromatography-mass spectrometry (LC-MS)is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography (aka HPLC) with the mass analysis capabilities of mass spectrometry. LC-MS is a powerful technique used for many applications which has very high sensitivity and specificity. Generally its application is oriented towards the specific detection and potential identification of chemicals in the presence of other chemicals (in a complex mixture). ...more on Wikipedia about "Liquid chromatography-mass spectrometry"
Mass spectrometry is an analytical technique which determines the mass-to- charge (m/z) ratio of ions. It is most generally used to find the composition of a physical sample by generating a mass spectrum representing the masses of the components of a sample. It has several broad applications: ...more on Wikipedia about "Mass spectrometry"
The Mass spectrum of a sample of some substance is a pattern representing the distribution of particles ( atoms or molecules) by mass in the substance. It is usually aquired using an instrument called a mass spectrometer. Most mass spectrometers ionize the particles, so the mass spectra are graphs of relative abundance versus mass-to-charge ratio (m/z) of the ions. Some mass spectrometers break the particles into fragments whose relative abundance is measured; others observe the intact molecular masses without fragmentation. ...more on Wikipedia about "Mass spectrum"
Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique used in mass spectrometry, allowing, among others, to ionize biomolecules ( biopolymers like proteins, peptides and sugars) which tend to be more fragile and quickly lose structure when ionized by more conventional ionization methods. It is most similar in character to electrospray ionization both in relative softness and ions produced. ...more on Wikipedia about "Matrix-assisted laser desorption/ionization" It must be www.shortopedia.com. shortopedia
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