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Topic: Atomic absorption spectroscopy


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In the News (Sun 21 Jul 19)

  
  Absorption Spectroscopy
Absorption spectroscopy is used in chemistry and physics to identify the characteristic and unchanging absorption spectrum for specific elements and compounds.
The absorption of quanta of light by substances is determined by the promotion and demotion of electrons to and from atomic and molecular orbitals, and the measured wavelengths are individual and unique to each substance.
In absorption spectroscopy, x-rays can be used to reveal the chemical composition of a substance, and different isomers are revealed by near ultraviolet to near infrared wavelengths.
www.iscid.org /encyclopedia/Absorption_Spectroscopy   (205 words)

  
 Atomic Absorption
The principle used in atomic absorption spectroscopy was first discovered in 1802 by Wollaston when he observed the "Fraunhofer lines" or absorption lines in the spectrum of the sun.
In atomic absorption and atomic fluorescence spectroscopy, a light source is used to excite some of the ground state atoms in the flame.
In atomic absorption the method is based on the attenuation (weakening) of a beam of nearly monochromatic light as a consequence of its interaction with and partial absorption by the ground state atoms of the element being analyzed.
www.sonoma.edu /chemistry/chem115A/atomic.html   (1142 words)

  
 Atomic absorption spectroscopy - Wikipedia, the free encyclopedia
Atomic absorption spectroscopy in analytical chemistry is a technique for determining the concentration of a particular metal element within a sample.
Atomic Absorption Spectroscopy was first developed during the 1950s by a team of Australian chemists, lead by Alan Walsh, working at the CSIRO (Commonwealth Science and Industry Research Organisation) Division of Chemical Physics, in Melbourne Australia.
The absorption in the presence and absence of a magnetic field can be compared, the difference being the atomic absorption of interest.
en.wikipedia.org /wiki/Atomic_absorption_spectroscopy   (676 words)

  
 Atomic Absorption Spectroscopy, Atomic Emission Spectroscopy & Atomic Fluorescence Spectroscopy   (Site not responding. Last check: 2007-11-03)
Atomic Absorption Spectroscopy, Atomic Emission Spectroscopy & Atomic Fluorescence Spectroscopy
Atomic spectroscopy is the determination of elemental composition by its electromagnetic or mass spectrum.
Atomic absorption measures the amount of light at the resonant wavelength which is absorbed as it passes through a cloud of atoms.
www.andor.com /chemistry/?app=91   (995 words)

  
 Spectroscopy Summary
Unlike other spectroscopies in which the absorption, emission, or scattering of radiation is interpreted as a function of energy, photoelectron spectroscopy measures the kinetic energy of the electrons(s) ejected by x-ray radiation.
The measurement of the absorption, emission, or scattering of electromagnetic radiation by atoms or molecules is referred to as spectroscopy.
Spectroscopy is the study of spectra, that is, the dependence of physical quantities on frequency.
www.bookrags.com /Spectroscopy   (6000 words)

  
 Journal of Analytical-Science.com : Atomic Absorption Spectroscopy
Since atomic absorption is relatively inexpensive and fast and requires only a minimum of proper laboratory training, it is an excellent technique for performing first-run analyses of industrial metals.
Soils are ideal for atomic absorption since the particles are already in a finely ground state and often are composed of water-soluble metal salts that lend themselves readily to atomization and analysis.
Atomic absorption instruments are single beam, since it would be extremely difficult to produce a reference beam with its own nebulizer and flame identical to the sample beam.
www.analytical-science.com /Journal/atomicabsorption_2003.htm   (1729 words)

  
 Flame Atomic Absorption Spectrometry
The technique of flame atomic absorption spectroscopy (FAAS) requires a liquid sample to be aspirated, aerosolized, and mixed with combustible gases, such as acetylene and air or acetylene and nitrous oxide.
Flame atomic absorption hardware is divided into six fundamental groups that have two major functions: generating atomic signals and signal processing.
Atomic absorption spectrometry is a fairly universal analytical method for determination of metallic elements when present in both trace and major concentrations.
ewr.cee.vt.edu /environmental/teach/smprimer/aa/aa.html   (2188 words)

  
 Atomic absorption Spectroscopy
Atomic absorption methods measure the amount of energy (in the form of photons of light, and thus a change in the wavelength) absorbed by the sample.
Atomic absorption analysis involves measuring the absorption of light by vaporized ground state atoms and relating the absorption to concentration.
In atomic absorption (see schematic of an atomic-absorption experiment), there are two methods of adding thermal energy to a sample.
weather.nmsu.edu /Teaching_Material/soil698/Student_Reports/Spectroscopy/report.htm   (1829 words)

  
 Atomic Absorption Spectroscopy
Atomic absorption absorption spectroscopy (AA or AAS) is one of the commonest instrumental methods for analyzing for metals and some metalloids.
Since the basis for the AAS process is atomic ABSORPTION, the monochromator seeks to only allow the light not absorbed by the analyte atoms in the flame to reach the PMT.
The signal is therefore a decrease in measure light: atomic absorption spectroscopy.
www.shsu.edu /~chemistry/primers/AAS.html   (1209 words)

  
 Instant Notes In Spectroscopy
UV-Vis Spectroscopy is a technique which is based on the measurement of light absorbed by molecules and inorganic complexes.
Absorption and fluorescence (or emission) signals are mirror images of each other and occur close together.
The absorptions are plotted and that of the unknown is extrapolated down to the x -axis.
www-users.york.ac.uk /~srms500/siti.org.uk/notes/spectroscopy.html   (1663 words)

  
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Since the transitions are between distinct atomic energy levels, the emission lines in the spectra are narrow.
Most absorption spectroscopy of organic compounds is based on transitions of n or p electrons to the p* excited state.
This is because the absorption peaks for these transitions fall in an experimentally convenient region of the spectrum (200 - 700 nm).
www.lycos.com /info/spectroscopy--miscellaneous.html   (432 words)

  
 Spectroscopy...Astroppo.com
Spectroscopy is often used in physical and analytical chemistry for the identification of substances, through the spectrum emitted or absorbed.
The intensity of emitted electromagnetic radiation and the amount of absorbed electromagnetic radiation is studied by electromagnetic spectroscopy.
For example, UV/Vis absorption spectroscopy is most often performed on liquid samples to detect molecular content and IR spectroscopy is most often performed on dried samples to to determine molecular information, including structureal information.
www.astroppo.com /spectroscopy.html   (313 words)

  
 Atomic Emission Spectroscopy   (Site not responding. Last check: 2007-11-03)
Atomic emission spectroscopy (AES or OES) uses quantitative measurement of the optical emission from excited atoms to determine analyte concentration.
As in AA spectroscopy, the sample must be converted to free atoms, usually in a high-temperature excitation source.
Since the atomic emission lines are very narrow, a high-resolution polychromator is needed to selectively monitor each emission line.
elchem.kaist.ac.kr /vt/chem-ed/spec/atomic/aes.htm   (252 words)

  
 Atomic-Absorption Spectroscopy   (Site not responding. Last check: 2007-11-03)
Atomic-absorption (AA) spectroscopy uses the absorption of light to measure the concentration of gas-phase atoms.
Applying the Beer-Lambert law directly in AA spectroscopy is difficult due to variations in the atomization efficiency from the sample matrix, and nonuniformity of concentration and path length of analyte atoms (in graphite furnace AA).
The main purpose of the monochromator is to isolate the absorption line from background light due to interferences.
elchem.kaist.ac.kr /vt/chem-ed/spec/atomic/aa.htm   (384 words)

  
 Atomic Absorption Spectroscopy   (Site not responding. Last check: 2007-11-03)
Atomic absorption spectroscopy (AAS) is the measurement of an absorption of optical radiation by atoms in the gaseous state.
Sample cell - Where an atomic sample vapor is generated in the light beam from the source.
This is usually done by introducing the sample into a burner system (Flame AAS) or electrically heated furnace or platform, aligned in the optical path of the spectrophotometer.
www.chemistry.nmsu.edu /Instrumentation/AAS1.html   (202 words)

  
 Atomic Absorption Spectroscopy Instrumentation:
The Varian 220 FS is used for flame-source atomic absorption analysis of aqueous solutions and vapors.
The atomic absorption spectrometers were purchased through a National Science Foundation grant titled, "Improving Curricula in Chemistry and Geology by the Integration of Environmentally Relevant Atomic Absorption Spectroscopy Throughout Undergraduate Studies," awarded to Dr. Daniel Lowy, Dr. Richard Petersen, and Dr. Dan Larsen.
The purpose of the grant is to provide modern atomic absorption instrumentation for analysis of environmentally relevant materials (e.g., Pb-based paint, Na in soft drinks, aqueous chemistry of municipal water supplies and runoff) in undergraduate courses, including CHEM 4604 (Instrumental Methods), CHEM 3201 (Quantitative Analysis), CHEM 4001 (Environmental Chemistry), and GEOL 4341 (Aqueous Geochemistry).
www.chem.memphis.edu /instruments/aalab.htm   (296 words)

  
 Chemical Analysis Techniques - X-Ray Fluorescence, Optical Emission Spectroscopy, Atomic Absorption
This method is used by Incotest to determine trace and residual impurity elements and is particularly useful for low atomic number elements such as boron, magnesium, aluminium, phosphorous and calcium.
Residual and trace elements are analysed using Atomic Absorption and Graphite Furnace Atomisation (GFA).
The sample is melted in an inert gas stream in a graphite crucible and the gasses evolved are measured by thermal conductivity or infra-red absorption.
www.azom.com /details.asp?ArticleID=2550   (548 words)

  
 Spectroscopy Software: mass spectrometry Near Infrared (NIR) Spectroscopy NMR Spectroscopy Atomic Absorption ...
Spectroscopy is a technique that uses the interaction of energy with a sample to perform an analysis.
A spectrum is a plot of the intensity of energy detected versus the wavelength (or mass or momentum or frequency, etc.) of the energy.
In simplest terms, spectroscopy requires an energy source and a device for measuring the change in the energy source after it has interacted with the sample (a spectrophotometer or interferometer).
www.camo.com /rt/Resources/spectroscopy.html   (314 words)

  
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The theory of atomic absorption spectroscopy, a description of how the instrument enables the measurement of absorbance to be made in the flame, and the possible sources of error should be discussed in the introduction.
Since theoretically atomic absorption spectroscopy is based upon Beer’s Law, a linear relationship, include in your discussion why we use the non-linear parameter.
In the Conclusions section, compare the applicability of atomic absorption spectroscopy for elemental metal analysis to other common methods of analysis along with any conclusions you can draw from your experimental results.
pages.pomona.edu /~wsteinmetz/chem160/AASlabmanual.doc   (3072 words)

  
 Atomic Absorption and Emission Spectra
An absorption spectrum occurs when light passes through a cold, dilute gas and atoms in the gas absorb at characteristic frequencies; since the re-emitted light is unlikely to be emitted in the same direction as the absorbed photon, this gives rise to dark lines (absence of light) in the spectrum.
Emission or absorption processes in hydrogen give rise to series, which are sequences of lines corresponding to atomic transitions, each ending or beginning with the same atomic state in hydrogen.
Because of the details of hydrogen's atomic structure, the Balmer Series is in the visible spectrum and the Lyman Series is in the the UV.
csep10.phys.utk.edu /astr162/lect/light/absorption.html   (408 words)

  
 EXPERIMENT 7.<p>Atomic Absorption Spectroscopy   (Site not responding. Last check: 2007-11-03)
You will learn about the principles and operation of an atomic absorption spectrometer, an instrument frequently used to analyze trace elements.
Before starting the experiment you must have read the chapter on Flame Emission and Atomic Absorption Spectrometry in the book by Willard, Merrit and Dean, and studied the accompanying instructions about the operation of our instrument.
Explain why the detection limits in the emission mode and the absorption mode are different.
www.chem.brown.edu /chem116/labs/exp7.html   (574 words)

  
 Spectroscopy : Types of Spectroscopy   (Site not responding. Last check: 2007-11-03)
Attenuated total reflectance spectroscopy and the related technique called frustrated multiple internal reflection spectroscopy are used to analyze coatings and opaque liquids.
Absorption spectroscopy, fluorescence spectroscopy, Raman spectroscopy, and surface-enhanced Raman spectroscopy commonly use laser light as an energy source.
In this type of spectroscopy, each optical wavelength that is recorded is encoded with an audio frequency containing the original wavelength information.
www.camo.com /rt/Resources/types_spectroscopy.html   (496 words)

  
 Trace Element Research Laboratory (TERL)
Gaseous Hgo enters the sweep gas and is introduced into an atomic absorption cell, where light produced by a mercury vapor lamp is absorbed by the free Hg atoms.
Flame atomic absorption spectrophotometry relies on a flame to provide the heat necessary to evaporate the solvent (water) and break molecular bonds in order to produce a cloud of free atoms in the path of an atomic absorption spectrophotometer.
Concentrations of trace elements in water samples are determined with an atomic spectroscopy method that relies on ionization of sample constituents in a high temperature argon plasma and separation of positively-charged ions on the basis of their mass:charge ratios (m:z) by a quadrupole mass spectrometer.
www.fws.gov /chemistry/methods_terl_lab.htm   (3272 words)

  
 Analyzing Rocket Exhaust by Atomic-Absorption Spectroscopy
Although the design of the system is specific to this rocket-engine-testing application, it may be adaptable to other applications that involve similar geometry, physical conditions, and chemical constituents of flowing gases.
The system schematic includes a source probe that generates an optical emission spectrum characteristic of the atomic species expected to be entrained in the rocket exhaust.
The source probe is aligned so that the optical signal passes through the center line of the exhaust plume downstream from the rocket-engine nozzle where it is collected by the receiver probe.
www.nasatech.com /Briefs/Mar00/SSC00062.html   (430 words)

  
 Atomic Absorption and Atomic Spectroscopy Resource
Atomic absorption spectroscopy was key to research that really gets to the heart of the problem of arterial plaques.
Xi-Ming Yuan of Linköping University, Sweden, and colleagues there and at the University of Louisville, Kentucky, have identified the toxic components of arterial plaques seen in atherosclerosis, that kill the white blood cells that would otherwise help the body break down the plaques.
Register now to receive free monthly email newsletters bringing you the latest news and features in spectroscopy, and to access restricted areas of the site.
www.spectroscopynow.com /coi/cda/home.cda?chId=1   (296 words)

  
 Atomic absorption spectroscopy
To determine the iron content in a 'Milo' milk drink, a 5ml sample was diluted to 50ml.
the absorption of the diluted solution and of several standard solution were measured using AAS.
Convert the first number into moles (from the atomic wt of Fe) and the second into a volume (assuming the density as above), and you are done.
www.physicsforums.com /showthread.php?t=74901   (411 words)

  
 Gateway to Optical Emission Spectroscopy and Emission Spectrometry   (Site not responding. Last check: 2007-11-03)
The Spectroscopy Net is an open, free resource for Spectroscopists everywhere and everyone interested in Atomic Spectroscopy.
Those seeking other spectroscopies, in particular we have lots of requests for atomic absorption spectroscopy, might try our Other Spectroscopies or Related Sites.
Educational: contains history, nature of light, sun and stars, optical spectroscopy, instruments and components (diffraction gratings, optical spectrometers, detectors), samples and definitions.
thespectroscopynet.com   (538 words)

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