Atomic Absorption Spectroscopy (AAS) is one of the most important techniques used in analytical chemistry for the accurate determination of metal elements. This technique is based on the principle that free atoms absorb electromagnetic radiation at specific wavelengths, where each element has a characteristic absorption spectrum that allows its identification and quantification in a sample. In this technique, the sample is first converted into free atoms through a process known as atomization, which is typically carried out using a flame or a graphite furnace. A light beam of a specific wavelength is then passed through the sample. As the atoms absorb the light, the intensity of the transmitted beam decreases, and this reduction is measured to determine the concentration of the element using the Beer–Lambert law. Atomic Absorption Spectroscopy is characterized by high sensitivity and the ability to detect very small amounts of elements, making it suitable for analyzing environmental samples such as water and soil, as well as biological samples like blood and urine. It is also widely used in the food and pharmaceutical industries for quality control and for detecting toxic metals such as lead and cadmium. The accuracy of this technique depends on several factors, including the type of radiation source, the efficiency of the atomization process, and the absence of chemical or spectral interferences. Therefore, background correction techniques and careful sample preparation are essential to obtain reliable results. This technique has also been developed into more advanced forms, such as graphite furnace atomic absorption spectroscopy, which provides higher sensitivity compared to flame AAS. In addition, cold vapor atomic absorption spectroscopy is specifically used for mercury analysis due to its high selectivity and precision. Atomic Absorption Spectroscopy remains a fundamental tool in modern analytical laboratories, providing fast and accurate results across various fields including environmental monitoring, medicine, industry, and scientific research. Al-Mustaqbal University, the leading private university in Iraq