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Quadrupole Mass Analyzers
The quadrupole mass analyzer, originally conceived by Nobel Laureate Wolfgang Paul and his student Helmut Steinwedel, also known as quadrupole mass filter, is one type of mass analyzer used in mass spectrometry. As the name implies, it consists of four cylindrical rods, set parallel to each other. In a quadrupole mass spectrometer (QMS) the quadrupole is the ''mass analyzer'' - the component of the instrument responsible for selecting sample ions based on their mass-to-charge ratio (''m/z''). Ions are separated in a quadrupole based on the stability of their trajectories in the oscillating electric fields that are applied to the rods. Principle of operation The quadrupole consists of four parallel metal rods. Each opposing rod pair is connected together electrically, and a radio frequency (RF) voltage with a DC offset voltage is applied between one pair of rods and the other. Ions travel down the quadrupole between the rods. Only ions of a certain mass-to-charge ratio will reach t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Spectrometer Quadrupole
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary particles, theoretically with the same amount of matter, have nonetheless different masses. Mass in modern physics has multiple definitions which are conceptually distinct, but physically equivalent. Mass can be experimentally defined as a measure of the body's inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. The object's mass also determines the strength of its gravitational attraction to other bodies. The SI base unit of mass is the kilogram (kg). In physics, mass is not the same as weight, even though mass is often determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. An object on the Moon would weigh less t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tandem Mass Spectrometry
Tandem mass spectrometry, also known as MS/MS or MS2, is a technique in instrumental analysis where two or more mass analyzers are coupled together using an additional reaction step to increase their abilities to analyse chemical samples. A common use of tandem MS is the analysis of biomolecules, such as proteins and peptides. The molecules of a given sample are ionized and the first spectrometer (designated MS1) separates these ions by their mass-to-charge ratio (often given as m/z or m/Q). Ions of a particular m/z-ratio coming from MS1 are selected and then made to split into smaller fragment ions, e.g. by collision-induced dissociation, ion-molecule reaction, or photodissociation. These fragments are then introduced into the second mass spectrometer (MS2), which in turn separates the fragments by their m/z-ratio and detects them. The fragmentation step makes it possible to identify and separate ions that have very similar m/z-ratios in regular mass spectrometers. Struc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Diagnostics
Plasma diagnostics are a pool of methods, instruments, and experimental techniques used to measure properties of a Plasma (physics), plasma, such as plasma components' density, distribution function over energy (temperature), their spatial profiles and dynamics, which enable to derive plasma parameters. Invasive probe methods Ball-pen probe A ball-pen probe is novel technique used to measure directly the plasma potential in magnetized plasmas. The probe was invented by Jiří Adámek in the Institute of Plasma Physics AS CR in 2004. The ball-pen probe balances the electron saturation current to the same magnitude as that of the ion saturation current. In this case, its Langmuir probe, floating potential becomes identical to the plasma potential. This goal is attained by a ceramic shield, which screens off an adjustable part of the electron current from the probe collector due to the much smaller gyro–radius of the electrons. The electron temperature is proportional to the differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Residual Gas Analyzer
A residual gas analyzer (RGA) is a small and usually rugged mass spectrometer, typically designed for process control and contamination monitoring in vacuum systems. When constructed as a quadrupole mass analyzer, there exist two implementations, utilizing either an open ion source (OIS) or a closed ion source (CIS). RGAs may be found in high vacuum applications such as research chambers, surface science setups, accelerators, scanning microscopes, etc. RGAs are used in most cases to monitor the quality of the vacuum and easily detect minute traces of impurities in the low-pressure gas environment. These impurities can be measured down to 10^ Torr levels, possessing sub- ppm detectability in the absence of background interferences. RGAs would also be used as sensitive in-situ leak detectors commonly using helium, isopropyl alcohol or other tracer molecules. With vacuum systems pumped down to lower than 10^ Torr—checking of the integrity of the vacuum seals and the quality ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Chromatography-mass Spectrometry
Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). A gas mixture, such as air, contains a variety of pure gases. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colourless gas invisible to the human observer. The gaseous state of matter occurs between the liquid and plasma states, the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super-cooled to very low temperatures are classified by their statistical behavior as either Bose gases or Fermi gases. For a comprehensive listi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Chromatography-mass Spectrometry
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, and plasma), and is the only state with a definite volume but no fixed shape. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds. Like a gas, a liquid is able to flow and take the shape of a container. Most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly constant density. A distinctive property of the liquid state is surface tension, leading to wetting phenomena. Water is by far the most common liquid on Earth. The density of a liquid is usually close to that of a solid, and much higher than that of a gas. Therefore, liquid and solid are both termed condensed matter. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrupole Time-of-flight Mass Spectrometer
A hybrid mass spectrometer is a device for tandem mass spectrometry that consists of a combination of two or more '' m/z'' separation devices of different types. Notation The different ''m/z'' separation elements of a hybrid mass spectrometer can be represented by a shorthand notation. The symbol ''Q'' represents a quadrupole mass analyzer, ''q'' is a radio frequency collision quadrupole, ''TOF'' is a time-of-flight mass spectrometer, ''B'' is a magnetic sector and ''E'' is an electric sector. Sector quadrupole A sector instrument can be combined with a collision quadrupole and quadrupole mass analyzer to form a hybrid instrument. A BEqQ configuration with a magnetic sector (B), electric sector (E), collision quadrupole (q) and ''m/z'' selection quadrupole (Q) have been constructed and an instrument with two electric sectors (BEEQ) has been described. Quadrupole time-of-flight A triple quadrupole mass spectrometer with the final quadrupole replaced by a time-of-flight device i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time-of-flight
Time of flight (ToF) is the measurement of the time taken by an object, particle or wave (be it acoustic, electromagnetic, etc.) to travel a distance through a medium. This information can then be used to measure velocity or path length, or as a way to learn about the particle or medium's properties (such as composition or flow rate). The traveling object may be detected directly (direct time of flight, dToF, e.g., via an ion detector in mass spectrometry) or indirectly (indirect time of flight, iToF, e.g., by light scattered from an object in laser doppler velocimetry). Overview In electronics, one of the earliest devices using the principle are ultrasonic distance-measuring devices, which emit an ultrasonic pulse and are able to measure the distance to a solid object based on the time taken for the wave to bounce back to the emitter. The ToF method is also used to estimate the electron mobility. Originally, it was designed for measurement of low-conductive thin films, later adjus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sector Instrument
A sector instrument is a general term for a class of mass spectrometer that uses a static electric (E) or magnetic (B) sector or some combination of the two (separately in space) as a mass analyzer. Popular combinations of these sectors have been the EB, BE (of so-called reverse geometry), three-sector BEB and four-sector EBEB (electric-magnetic-electric-magnetic) instruments. Most modern sector instruments are double-focusing instruments (first developed by Francis William Aston, Arthur Jeffrey Dempster, Kenneth Bainbridge and Josef Mattauch in 1936) in that they focus the ion beams both in direction and velocity. Theory The behavior of ions in a homogeneous, linear, static electric or magnetic field (separately) as is found in a sector instrument is simple. The physics are described by a single equation called the Lorentz force law. This equation is the fundamental equation of all mass spectrometric techniques and applies in non-linear, non-homogeneous cases too and is an impor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid Mass Spectrometer
A hybrid mass spectrometer is a device for tandem mass spectrometry that consists of a combination of two or more '' m/z'' separation devices of different types. Notation The different ''m/z'' separation elements of a hybrid mass spectrometer can be represented by a shorthand notation. The symbol ''Q'' represents a quadrupole mass analyzer, ''q'' is a radio frequency collision quadrupole, ''TOF'' is a time-of-flight mass spectrometer, ''B'' is a magnetic sector and ''E'' is an electric sector. Sector quadrupole A sector instrument can be combined with a collision quadrupole and quadrupole mass analyzer to form a hybrid instrument. A BEqQ configuration with a magnetic sector (B), electric sector (E), collision quadrupole (q) and ''m/z'' selection quadrupole (Q) have been constructed and an instrument with two electric sectors (BEEQ) has been described. Quadrupole time-of-flight A triple quadrupole mass spectrometer with the final quadrupole replaced by a time-of-flight device i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Yost
Richard A Yost (born 31 May 1953 in Martins Ferry) is an American scientist and a professor at the University of Florida. He is best known for his work inventing the triple quadrupole mass spectrometer.The Encyclopedia of Mass Spectrometry: Volume 9: Historical Perspectives, Part B: Notable People in Mass Spectrometry Yost received his BS degree in Chemistry in 1974 from the University of Arizona, having performed undergraduate research in chromatography with Mike Burke and his PhD degree in Analytical Chemistry in 1979 from Michigan State University, having performed graduate research with Chris Enke. He joined the faculty of the University of Florida after his graduate research. He is director of the Southeast Center for Integrated Metabolomics (SECIM) and of NIH's Metabolomics Consortium Coordinating Center (M3C). He is also a Professor of Pathology at both the University of Florida and the University of Utah/ ARUP. His professional activities have focused on researc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christie G
Christie can refer to: People: * Christie (given name) * Christie (surname) * Clan Christie Other uses: * Christie's, the auction house * Christie, the Canadian division of Nabisco * Christie (TTC), subway station in Toronto, Ontario, Canada * Christie (company), a digital projection company * Christie (band), UK rock band * Christie Hospital, Manchester, England, researches and treats cancer ** The Christie NHS Foundation Trust, manages the Christie Hospital * Christie suspension, vehicle (tank) suspension system invented by U.S. engineer Walter Christie * Christie Organ, a brand of theatre pipe organ * ''Get Christie Love!'', an American crime drama TV series starring Teresa Graves * Christie (Dead or Alive), a video game character in ''Dead or Alive 3'' See also * Christy (other) Christy may refer to: * Christy (given name) * Christy (surname) * ''Christy'' (novel), by Catherine Marshall * Christy (towel manufacturer), a UK textile firm established in 1850 * ''C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
