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Related to Quadrapole: Quadrupole moment, octupole


A distribution of charge or magnetization which produces an electric or magnetic field equivalent to that produced by two electric or magnetic dipoles whose dipole moments have the same magnitude but point in opposite directions, and which are separated from each other by a small distance.
A mass distribution that has unequal components of the moment-of-inertia tensor along the three principal directions.



a system of charged particles whose total electric charge and electric dipole moment equal zero.

Figure 1. Examples of relative location of dipoles in a quadrupole

A quadrupole can be considered a set of two identical dipoles with the dipole moments equal in magnitude but opposite in direction and separated by a certain distance. At great distances R from the quadrupole, the field intensity of the quadrupole E decreases in inverse proportion to R to the fourth power (E∼ 1/R4). The relationship between E and the charges and their location is described in the general case by a set of five independent values that together constitute the quadrupole moment of the system. The quadrupole moment also determines the energy of a quadrupole in an external electric field. In the case described by Figure 1 the absolute value of the quadrupole moment is equal to 2ela, where e is the charge, 1 is the dimension of the dipoles, and a is the distance between the centers of the dipoles. A quadrupole is a second-order multipole.


Landau, L. D., and E. M. Lifshits. Teoriia polia, 5th ed. Moscow, 1967, § 41.


References in periodicals archive ?
2]O and spiked with proper amount of labeled peptides for both multiple reaction monitering (MRM) using ChipCube triple quadrapole (QQQ) and targeted LC-MS/MS using Q-TOF.
The new system analyses the majority of elements in the periodic table by ionising species to the +1 state, followed by Quadrapole Mass Spectrometry analysis of the ionised species.
QIAquick 96 PCR purification cartridges (Qiagen, Hilden, Germany, with modified binding and wash buffers) were used to remove unincorporated primers before tags were decoupled from amplification products by UV photolysis in a flow cell and analyzed in a quadrapole mass spectrometer by using positive-mode atmospheric pressure chemical ionization (APCI-MS, Agilent Technologies, Palo Alto, CA, USA).
Mike started with a small floating quadrapole experiment and quickly became involved with the ORNL effort to design, build and operate the first US all-new tokamak, ORMAK.
For diazinon and malathion, UCD used a gas chromatograph with a DB-17 capillary column and a quadrapole mass spectrometer operated in selected ion mode (CARB 1998b, 1999).
The mass spectrometer used was a Hewlett Packard 5973 mass selective detector with a quadrapole analyzer in full scan mode (range: 50-550).
The GC/MS analysis was performed using a Hewlett-Packard GC-MS system consisting of an HP 6890 gas chromatograph and an HP quadrapole mass selective detector.
During the past decade, most characterization and some quantitation of trace level organic compounds has been acquired using a quadrapole type GC/MS.
Tenders are invited for Supply of High resolution Liquid Chromatography with Triple quadrapole Mass Spectrometer
Masscode tags were decoupled from amplified products through UV light-induced photolysis in a flow cell and analyzed in a single quadrapole mass spectrometer using positive-mode atmospheric pressure chemical ionization (Agilent Technologies, Palo Alto, CA, USA).
Recent collaboration with Waters and GSK have linked both Parallex and Parallex-Flex, running four columns in synchrony, to a Waters ZQ single quadrapole mass spectrometer using the MUX interface.