When a substance is in vapor form, the frequency of light it will absorb changes and is distinct to every element. Analyzing the spectrum of light a substance produces when vaporized enables us to identify its elemental composition and the concentration levels of each component in it. This process is what is known as atomic absorption spectroscopy.
Atomic absorption spectroscopy (AAS) was initially employed in 1800s to identify the atoms present in flames and gases. However, since then, the use of atomic absorption spectroscopy has evolved. In modern days, it is used in scientific research, especially in identifying the concentrations of metal ions in a substance.
Types Of Atomic Absorption Spectroscopy
Flame Atomic Absorption Spectroscopy (FAAS)
Flame atomic absorption spectroscopy is used in labs to analyze the presence of metals in solutions. The metal ions are nebulized as fine spray and converted into a high-temperature flame. They are then reduced to their atoms that distinctly absorb light from an element-specific hollow cathode lamp. This process has proven to be robust and excellent for routine metal analysis.
Graphite Furnace Atomic Absorption Spectroscopy (GFAAS)
Graphite furnace atomic absorption spectroscopy is more sensitive than FAAS. It is generally used to detect very low concentrations of metals in substances. Unlike FAAS that uses a flame to atomize the sample, in GFAAS, a narrow carbon tune atomizes the substance, improving sensitivity and detection due to the absence of spectral noise from the flame. That ensures the sample is completely atomized.
Applications of AAS
Atomic absorption spectroscopy is used to detect and trace metals in a wide range of sample types in various industries, including food, beverage, environmental science, chemistry labs, and pharmaceutical industries. It is used for the assessment of raw materials, contamination, and quality control. In the clinical sector, atomic absorption spectroscopy analyzes biological fluids such as urine and blood samples.
Benefits of AAS
Atomic absorption spectroscopy is a highly sensitive detection technique. It can measure up to parts per billion of a gram in a sample. As a result, it has changed the way certain scientific practices are carried out in many industries. A good example is in medicine. It is used to detect toxin levels of medication and atmosphere.
In the pharmaceutical sector, through atomic absorption spectroscopy, the unwanted trace elements of a catalyst that has sometimes been in the final product can be identified. In the agricultural industry, AAS can be used to trace the elements previously unknown, such as cobalt, to research their importance, presence, or absence in soil.
Atomic absorption spectroscopy produces accurate results. Typically it gives results with a rate of 0.5-5% accuracy and is capable or a better rate if proper standards are used.
Since it relies on light absorption and radiation, atomic absorption spectroscopy can access previously inaccessible places. For instance, a miner can use AAS to find if a rock contains enough elements of metal that worth mining.
The running costs of atomic absorption spectroscopy are few because it uses less argon than other methods.
The Bottom Line
Atomic absorption spectroscopy is easy to use, inexpensive while still providing a high quantitative analysis of the metal content in a solid or liquid sample.