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Flame atomic absorption spectroscopy instrument A scientist preparing solutions for atomic absorption spectroscopy, reflected in the glass window of the AAS's flame atomizer cover door. Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for the quantitative measurement of chemical elements. AAS is based on the absorption of ...
In structural biology, resolution can be broken down into 4 groups: (1) sub-atomic, when information about the electron density is obtained and quantum effects can be studied, (2) atomic, individual atoms are visible and an accurate three-dimensional model can be constructed, (3) helical, secondary structure, such as alpha helices and beta sheets; RNA helices (in ribosomes), (4) domain, no ...
The absorption spectrum is primarily determined [2] [3] [4] by the atomic and molecular composition of the material. Radiation is more likely to be absorbed at frequencies that match the energy difference between two quantum mechanical states of the molecules .
absorption: 1) The process of one material (absorbate) being retained by another (absorbent); this may be the physical solution of a gas, liquid, or solid in a liquid, attachment of molecules of a gas, vapour, liquid, or dissolved substance to a solid surface by physical forces, etc. In spectrophotometry, absorption of light at characteristic ...
In atomic absorption spectroscopy, light of a predetermined wavelength is passed through a collection of atoms. If the wavelength of the source light has energy corresponding to the energy difference between two energy levels in the atoms, a portion of the light will be absorbed.
GFAA spectrometry instruments have the following basic features: 1. a source of light (lamp) that emits resonance line radiation; 2. an atomization chamber (graphite tube) in which the sample is vaporized; 3. a monochromator for selecting only one of the characteristic wavelengths (visible or ultraviolet) of the element of interest; 4. a detector, generally a photomultiplier tube (light ...
Adsorption (not to be mistaken for absorption) is the accumulation and adhesion of molecules, atoms, ions, or larger particles to a surface, but without surface penetration occurring. The adsorption of larger biomolecules such as proteins is of high physiological relevance , and as such they adsorb with different mechanisms than their molecular ...
When the atomic nucleus of an isotope is unstable, compounds containing this isotope are radioactive. Tritium is an example of a radioactive isotope. The principle behind the use of radioactive tracers is that an atom in a chemical compound is replaced by another atom, of the same chemical element.