Atomic Absorption Spectroscopy AAS (original) (raw)

ATOMIC ABSORPTION SPECTROSCOPY Principle

The basis of atomic absorption spectrometry (AAS) is the absorption of discrete wavelengths of light by ground state, gas phase free atoms. Free atoms in the gas phase are formed from the sample by an " atomizer " at high temperature. Theory: AAS was developed in the 1950s by Alan Walsh and rapidly became a widely used analytical tool. AAS is an elemental analysis technique capable of providing quantitative information on 70 elements in almost any type of sample. As an elemental analysis technique, it has the significant advantage in many cases of being practically independent of the chemical form of the element in the sample. A determination of cadmium in a water sample is a determination of the total cadmium concentration. It does not matter whether the cadmium exists as the chloride, sulphate, or nitrate, or even if it exists as a complex or an organ metallic compound, if the proper analysis conditions are used. Concentrations as low as ppt levels of some elements in solution can be determined and AAS is used routinely to determine ppb and ppm concentrations of most metal elements. Another principal advantage is that a given element can be determined in the presence of other elements, which do not interfere by absorption of the analyte wavelength. Therefore it is not necessary to separate the analyte from the rest of the sample (the matrix). This results in rapid analysis times and eliminates some sources of error. Disadvantages: • This is not to say that AAS measurements are completely free from interferences; both chemical and spectral interferences do occur and must be compensated for. • The major disadvantages of AAS are that no information is obtained on the chemical form of the analyte (no " speciation ") and that often only one element can be determined at a time. This last disadvantage makes AAS of very limited use for qualitative analysis. • AAS is used almost exclusively for quantitative analysis of elements, hence the use of the term " spectrometry " in the name of the technique instead of " spectroscopy " .

Atomic Absorption Spectroscopy

Atomic Absorption Spectroscopy is an analytical technique used for the qualitative and quantitative determination of the elements present in different samples like food, nanomaterials, biomaterials, forensics, and industrial wastes. The main aim of this book is to cover all major topics which are required to equip scholars with the recent advancement in this field. The book is divided into 12 chapters with an emphasis on specific topics. The first two chapters introduce the reader to the subject, it's history, basic principles, instrumentation and sample preparation. Chapter 3 deals with the elemental profiling, functions, biochemistry and potential toxicity of metals, along with comparative techniques. Chapter 4 discusses the importance of sample preparation techniques with the focus on microextraction techniques. Keeping in view the importance of nanomaterials and refractory materials, chapters 5 and 6 highlight the ways to characterize these materials by using AAS. The interference effects between elements are explained in chapter 7. The characterizations of metals in food and biological samples have been given in chapters 8-11. Chapter 12 examines carbon capture and mineral storage with the analysis of metal contents.

Atomic Absorption Spectroscopy (AAS) for Elemental Analysis of Plant Samples

Division of Plant Physiology, IARI, New Delhi, 2017

Mineral elements particularly metals play important role in biological system including plants. Magnesium (Mg) is in chlorophylls, iron (Fe) is in hemoglobin and cadmium (Cd) and aluminium (Al) are toxic to plant metabolism. A technique referred as atomic absorption spectroscopy (AAS) help in quantification of these elements and thereby their importance. AAS is therefore an important technique for agriculture (soil, plant, water and fertilizers analysis) and other areas including medical, feed stock, environment, pollution, industrial effluents metallurgy, oil industry and general inorganic analysis etc.