Definition of atomic absorption spectrophotometer

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atomic absorption spectrophotometer

An atomic absorption spectrometer (AAS) is an analytical instrument used to determine the concentration of specific chemical elements in a sample by measuring the absorption of light at characteristic wavelengths. It is commonly used in analytical chemistry for quantitative analysis of metals and metalloids in various samples, including environmental, biological, pharmaceutical, and industrial samples.

The principle behind atomic absorption spectroscopy involves the interaction of electromagnetic radiation (typically in the form of visible or ultraviolet light) with atoms in a sample. When light of a specific wavelength is passed through a sample containing the target element, the atoms of that element absorb energy from the light at discrete wavelengths corresponding to transitions between energy levels. The amount of absorption is directly proportional to the concentration of the element in the sample.

The basic components of an atomic absorption spectrometer typically include:

Light source: The spectrometer typically employs a hollow cathode lamp or other suitable light source that emits light at specific wavelengths corresponding to the absorption lines of the target elements.

Monochromator: A monochromator is used to isolate the desired wavelength of light from the light source and pass it through the sample.

Sample introduction system: The sample is introduced into the instrument using various methods, such as nebulization, flame, or graphite furnace atomization, depending on the sample type and the elements being analyzed.

Atomization system: The sample is atomized to convert the analyte into free atoms, which can absorb light at specific wavelengths.

Detector: A detector measures the intensity of the transmitted light after it has passed through the sample. The detector signal is then used to calculate the concentration of the target element in the sample.

Atomic absorption spectrometers offer several advantages, including high sensitivity, wide dynamic range, and relatively low detection limits. They are widely used in analytical laboratories for routine elemental analysis due to their accuracy, precision, and versatility in analyzing a wide range of sample types and elements.