what is an atomic absorption spectrophotometer?

Answer 1

An atomic absorption spectrophotometer is a device that can be used to detect elements in a sample of transparent media. Most typically it is used to measure elements in a gas. It works by shining a light through the sample and then looking at the spectrum of the light. The various atoms present in the sample will absorb characteristic wave lengths of light. By close examination of the spectrum, using a spectrophotometer, you can tell which elements are in the sample by the bands of "missing" light. That will be the light that the atom absorbed. Hence the name "atomic absorption spectrophotometer".

The technique can be made quantitative if you use a standard sample that is prepared with a known amount of the same elements you are trying to detect. By comparison of the unknown's intensity of the light in the absorption band with the known's intensity the concentration of the unknown can be deduced. Careful quantitative handling and dilution of the unknown sample is required for accurate results.

Depending upon what element you are looking for different light sources are required. They must put out light in the spectral region of the characteristic absorption lines.

The technique is useful for analysis of trace elemental quantities. Macro quantities can also be analyzed with sufficient dilution.

The technique is also used in astronomy to detect elements in outer space. It is basically the way we can figure out what stars and interstellar dust are made of.

The instrument is the spectrophotometer, the technique is called atomic absorption spectroscopy

Answer 2

Atomic absorption spectrophotometry provides accurate quantitative analyses for metals in water, sediments, soils or rocks. Atomic absorption units have four basic parts: interchangeable lamps that emit light with element-specific wavelengths, a sample aspirator, a flame or furnace apparatus for volatilizing the sample, and a photon detector. In order to analyze for any given element, a lamp is chosen that produces a wavelength of light that is absorbed by that element. Sample solutions are aspirated into the flame. If any ions of the given element are present in the flame, they will absorb light produced by the lamp before it reaches the detector. The amount of light absorbed depends on the amount of the element present in the sample. Absorbance values for unknown samples are compared to calibration curves prepared by running known samples.

Answer 3

you send the same amount of light through the thing you want to analyse (gaz, liquid or a slim slice of solid) and through void.
You analyse the light that comes out of both paths, and determine which wave lengths were absorbed.

The absorption graph is like a fingerprint for elements/molecules: it tells you who they are.