Atomic Absorption Spectroscopy is a very common technique for detecting metals and metalloids in samples.n It is very reliable and simple to use.n It can analyze over 62 elements.n It also measures the concentration of metals in the sample.The technique uses basically the principle that free atoms (gas) generated in an atomizer can absorb radiation at specific frequency.n Atomic-absorption spectroscopy quantifies the absorption of ground state atoms in the gaseous state .n The atoms absorb ultraviolet or visible light and make transitions to higher electronic energy levels. The analyte concentration is determined from the amount of absorption.Concentration measurements are usually determined from a working curve after calibrating the instrument with standards of known concentration.- Atomic absorption is a very common technique for detecting metals and metalloids in environmental samples. n Hollow Cathode Lamp are the most common radiation source in AAS.n It contains a tungsten anode and a hollow cylindrical cathode made of the element to be determined.n These are sealed in a glass tube filled with an inert gas (neon or argon ) .n Each element has its own unique lamp which must be used for that analysis. Elements to be analyzed needs to be in atomic sate.n Atomization is separation of particles into individual molecules and breaking molecules into atoms. This is done by exposing the analyte to high temperatures in a flame or graphite furnace n To create flame, we need to mix an oxidant gas and a fuel gas.n in most of the cases air-acetylene flame or nitrous oxide- acetylene flame is used.n liquid or dissolved samples are typically used with flame atomizer.A monochromator is used to select the specific wavelength of light which is absorbed by the sample, and to exclude other wavelengths.n The selection of the specific light allows the determination of the selected element in the presence of others.