Atomic absorption spectroscopy, animation

Référence de la vidéo 12081164
Atomic absorption spectroscopy. Animation showing the analytical technique of atomic absorption spectroscopy (AAS). This technique allows elements to be identified, and their concentration measured down to just a few parts per billion. The animation zooms in on one of the hollow-cathode lamps (HCLs), which emits light of a specific wavelength. The cathode is indicated by negative symbols (blue) and the anode by positive symbols (red). The wavelength of light emitted is specific to the element to be analysed, in this case copper (Cu). Atoms of the inert noble gas argon (Ar) are shown bouncing off the copper cathode. An inset shows an electron in the outer levels of a copper atom being excited to a higher level and dropping back to its original state, emitting a photon of light in the process. These wavelengths of light are specific energy quanta which can only be absorbed by the electrons of the element under analysis. The animation then zooms in on the sample loading process, with copper sulphate solution (CuSO4) being added. Inside the absorption spectrometer, the sample is atomised or ionised when sprayed into the flame (green), producing Cu2+ ions. The atoms or ions in the sample (here Cu2+ ions) are shown absorbing the specific wavelengths of light emitted by the hollow-cathode lamp. An ion of iron (Fe2+) is shown failing to absorb a photon. The spectrometer measures the intensity (number of photons) of the light passing through the sample. When calibrated with samples of known concentrations, the detector can be used to measure the concentration of a particular chemical, in this case copper. The results (not shown) would be displayed on the screen at right.
Licence : Droits gérés
Crédit : Science Photo Library / EQUINOX GRAPHICS / RHYS LEWIS, AHS, DECD, UNISA
Model Release : Non requis
Durée : 01:36 Minutes
Aspect ratio : 16/9
Restrictions : -

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