Quadrupole
Quadrupole - Related Videos
08:10
Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry
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Cited by 16 •
2017
Fizzy extraction is a new laboratory technique for analysis of volatile and semivolatile compounds. A carrier gas is dissolved in the liquid sample by applying overpressure and stirring the sample. The sample chamber is then decompressed. The analyte species are liberated to the gas phase due to effervescence.
04:19
An Improved Technique for Trimethylamine Detection in Animal-Derived Medicine by Headspace Gas Chromatography-Tandem Quadrupole Mass Spectrometry
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Cited by 2 •
2023
Here, a headspace gas chromatography-tandem quadrupole mass spectrometry (HS-GC-MS/MS) method suitable for the determination of trimethylamine (TMA) in animal-derived medicines is described. The protocol includes sample pretreatment, headspace treatment, analysis conditions, methodological validation, and the determination of TMA in animal-derived medicines.
09:21
Mössbauer Spectroscopy
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2023
Source: Joshua Wofford, Tamara M. Powers, Department of Chemistry, Texas A&M University Mössbauer spectroscopy is a bulk characterization technique that examines the nuclear excitation of an atom by gamma rays in the solid state. The resulting Mössbauer spectrum provides information about the oxidation state, spin state, and electronic environment around the target atom, which, in combination, gives evidence about the electronic structure and ligand arrangement (geometry) of the molecule.
13:45
Introduction to Mass Spectrometry
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2023
Source: Laboratory of Dr. Khuloud Al-Jamal - King's College London Mass spectrometry is an analytical chemistry technique that enables the identification of unknown compounds within a sample, the quantification of known materials, the determination of the structure, and chemical properties of different molecules. A mass spectrometer is composed of an ionization source, an analyzer, and a detector. The process involves the ionization of chemical compounds to generate ions. When using...
14:11
Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis
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Cited by 21 •
2016
We illustrate the application of 1H(15N,αγ)12C resonant nuclear reaction analysis (NRA) to quantitatively evaluate the density of hydrogen atoms on the surface, in the volume, and at an interfacial layer of solid materials. The near-surface hydrogen depth profiling of a Pd(110) single crystal and of SiO2/Si(100) stacks is described.
FAQs
The key interaction occurs when an electric-field gradient couples to a quadrupolar nucleus. This coupling changes the nucleus’s energy levels according to its local electrostatic environment, so the resulting spectral behavior reflects how charge is arranged around it. In chemistry, that makes quadrupole effects useful for examining local bonding environments rather than treating the molecule as a simple dipole.
A molecular quadrupole adds second-order charge-distribution information beyond a dipole description. A dipole represents a simpler separation of charge, whereas the quadrupole component captures a more detailed arrangement involving four poles. This distinction matters when electric interactions depend on the distribution and orientation of charge, allowing structural behavior to be interpreted more fully.
The interaction between a charge distribution or nucleus and an uneven electric-field gradient depends on how the relevant fields are arranged relative to one another. Consequently, quadrupole effects can alter energy levels and preferred orientations, producing changes in spectra. These changes provide chemical information about the local environment surrounding the interacting nucleus or molecule.
A quadrupole mass spectrometer uses oscillating electric fields to selectively stabilize ions with particular mass-to-charge ratios. By applying this field-based selection, the instrument distinguishes ions according to their mass-to-charge behavior rather than simply their total charge. The resulting selection supports chemical identification and analysis of the species present in a sample.
In NMR and microwave spectroscopy, quadrupolar nuclei can provide information about molecular structure and local bonding environments. Their interactions with electric-field gradients affect observable energy levels and spectral features, linking measurements to the surrounding charge arrangement. Chemists can therefore use these spectroscopic effects to investigate how bonding and molecular structure vary in different environments.
Quadrupole-based analysis is useful when chemical identification depends on distinguishing ions by their mass-to-charge ratios. The instrument’s oscillating electric fields select ions with specific values, creating an analytical basis for separating chemical signals according to that property. This application extends quadrupole principles from molecular charge interactions to practical instrument-based analysis of chemical composition.