In this lesson we discuss how atomic absorption spectroscopy Works and the important role it plays in understanding the possible health effects of trace metal contamination. Because of popular culture, you probably think of toxin, or a dangerous compound. You would be right to believe this. Arsenic is an element found in many distinct products with several uses. It is naturally occurring and quite abundant. Unfortunately, arsenic is occasionally found in soil water, and then, plants are exposed to arsenic. This poses possible negative health effects to people who consume the contaminated plants or water. Consumed in large doses, arsenic poisoning finally leads to death. However, there are negative effects of consuming arsenic in smallish doses. Arsenic is carcinogenic, a chemical which causes cancer, and is connected to a lot of negative health effects such as heart disease.
To help mitigate some of the negative effects, food and water shouldn’t exceed recommended amounts of arsenic. The recommend levels are extremely small, on the order of 10 parts per billion. Atomic spectroscopy is capable of measuring components, like Arsenic, in tiny concentrations. This ability has led to a lot of significant observations, largely how trace metals can negatively affect our wellbeing. We will look at one instance of nuclear spectroscopy, atomic absorption spectroscopy AA or AAS, to determine how it is able to detect small concentrations of components, or more specifically, metals. Spectroscopy is the branch of science which examines how matter interacts with electromagnetic radiation. In the event of atomic absorption spectroscopy, electromagnetic radiation, or light, is used to quantify electronic transitions. These electronic transitions are unique to the component being measured.
The schematic is a visual representation of emission and absorption. Electrons in atoms can be excited to higher energy levels, or higher energy electronic orbitals, by electromagnetic radiation. Photons are basically packeting of light using a predetermined amount of energy hv. If a photon of light with energy that corresponds to the difference between two energy levels strikes the atom, it is going to excite an electron into a higher energy level. This method is called absorption. Likewise, once an electron is in an excited state it may return to its ground state by giving off a photon of light that matches the difference in energy between the upper and lower energy levels. This process is known as emission. A spectrum is the wavelengths of light either absorbed or emitted by an atom or molecule. The spectrum, which corresponds to transitions between electronic energy levels, is exceptional. This enables us to identify atoms according to their own spectrum.