ATOMIC ABSORPTION SPECTROSCOPY by Faizan Akram
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This document provides an overview of atomic absorption spectroscopy (AAS), detailing its history, principles, instrumentation, and applications in analyzing metal concentrations in samples. AAS is a key technique for detecting metal and metalloid elements, utilizing various components like hollow cathode lamps, atomizers, and photomultiplier tubes for measurement. It is prominently used in fields such as pharmaceutical analysis, food industry, and mining to assess trace metals and impurities.
ATOMIC ABSORPTION SPECTROSCOPY by Faizan Akram
- 3. CONTENTS History Introduction to Atomic Absorption Spectroscopy Principle of Atomic Absorption Spectroscopy (AAS) Instrumentation. Applications.
- 4. HISTORY • The beautiful phenomenon of “RAINBOW” was the first dispersed spectrum. • In 1665 NEWTON took the first and the most important step towards the development of spectroscopy. • In 1859 G.R KIRCHOFF and R BUNSEN emerged as the FATHER OF MODERN SPECTROSCOPY.
- 5. ABSORPTION SPECTROSCOPY It gives the measurement of absorbed energy by the atom or molecule after which it excite and gives the absorbed energy in the form of absorption spectrum
- 6. ATOMIC ABSORPTION SPECTROSCOPY • Atomic absorption spectroscopy is a technique for determining the concentration of a particular metal element in a sample. Atomic absorption spectroscopy can be used to analyze the concentration of over 62 different metals in a solution.
- 8. “The atoms of metals are vaporized and their absorption of radiations produced by Hollow cathode tube which is made of same metal which is measured.” Atomic Absorption Spectroscopy is a very common technique for detecting metals and metalloids in samples. It also measures the concentration of metals in the sample.
- 12. Hollow Cathode Lamp are the most common radiation source in AAS. It contains a tungsten anode and a hollow cylindrical cathode made of the element to be determined. These are sealed in a glass tube filled with an inert gas (neon or argon ) . Each element has its own unique lamp which must be used for that analysis .
- 13. Hollow Cathode Lamp: Quartz window Pyrex body Anode Cathode cathode
- 14. suck up liquid samples at controlled rate. create a fine aerosol spray for introduction into flame. Mix the aerosol and fuel and oxidant thoroughly for introduction into flame.
- 15. Elements to be analyzed needs to be in atomic sate. 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 .
- 18. FLAME ATOMIZER: • Flame is used to atomize the sample • Sample when heated is broken into its atoms PRINCIPLE: • High temperature of flame causes excitation • Electrons of the atomized sample are promoted to higher orbitals, by absorbing certain amount of energy QUANTITATIVE ANALYSIS: • The amount of energy absorbed is specific for a particular element (for electronic transition). • Amount of absorbed radiation is a quantitative measure for the concentration of the element to be analyzed
- 19. NEBULIZER ASSEMBLY CONVERSION INTO FINE MIST & SMALL DROPLETS OF SOLUTION ASPIRATED INTO SPRAY CHAMBER (MIXING CHAMBER) AEROSOL MIXES WITH COMBUSTION GASES FLAME (ATOMIZATION OCCURS)
- 21. uses a graphite coated furnace to vaporize the sample. ln GFAAS sample, samples are deposited in a small graphite coated tube which can then be heated to vaporize and atomize the analyte. The graphite tubes are heated using a high current power supply.
- 22. • serves as sample cell. ( heating part of the graphite furnace).Graphite tube • Metal jacket by which the water is circulated .Enclosed water cooled housing • Made of quartz allow light to pass through the tube. Transparent windows • protect graphite tube from oxidationInert purge gas control • Heating of graphite tube Electrical contact
- 23. This is a very important part in an AA spectrometer. It is used to separate out all of the thousands of lines. A monochromator is used to select the specific wavelength of light which is absorbed by the sample, and to exclude other wavelengths. The selection of the specific light allows the determination of the selected element in the presence of others.
- 24. - Wavelength selectors - Produces monochromatic light Consists of: 1) Entrance slit 2) Diffraction grating 3) Exit slit Diffraction gratings are mostly used rather than prisms
- 25. The light selected by the monochromator is directed onto a detector that is typically a photomultiplier tube , whose function is to convert the light signal into an electrical signal proportional to the light intensity. The processing of electrical signal is fulfilled by a signal amplifier . The signal could be displayed for readout , or further fed into a data station for printout by the requested format.
- 26. Used to detect the light absorbed by the analyte . The ‘photomultiplier tube’ is used as detector in AAS
- 28. Operation of photomultiplier tube • Photo Emission • Secondary Emission
- 29. When light of less intensity falls on cathode, it causes the emission of electrons. These electrons are attracted towards the dynode, and strike at the first dynode D1 resulting the production of photoelectrons which are accelerated and focused to the next dynode, Thus producing more electrons to be focused onto the subsequent dynode. Eventually the electrons are collected at anode. This cascade effect makes this detector one of the most sensitive detector. Normally each photon striking cathode produces 106 to 109 electrons. The electrical signals of sample are compared with reference for the detection. PMT cannot be used to measure high intensity radiations because of non-linearity and instability. Working:
- 32. For detection of purity and consistency of these trace metals Also for quantitative determination of metals mainly in solid sample as mineral, ores and alloys
- 33. •Magnesium in cast iron • Silver, Zinc, Copper and Lead in Cadmium metal • Determination Of Trace Copper In Nickel Metal
- 34. Determination of trace metal in a silicon foam cavity wound dressing Zinc in Zinc insulin suspension and tetracosactrin Zinc injection Copper and Iron in ascorbic acid Aluminum in albumin solution and Ca, Mg, Mercury Zinc in water used for diluting haemodialysis solution
- 35. •For the analysis of pharmaceutically or therapeutically essential component of formulation, such as Zinc in Zinc-insulin, minerals in multivitamin-mineral preparation and Ca, Mg, Al in antacids. •To establish concentration limits where the metal is regarded as an impurity.
- 36. •Mining industries •Petroleum industries •Determination of metallic elements in food industry like Copper, Zinc and Nickel in vegetable oil and copper in beer.
- 37. Pharmaceutical Analysis: A Textbook for Pharmacy Students and Pharmaceutical Chemists By David G. Watson Mass Spectrometry Principles & Applications By ED Hoffmann & Stroobant. Mass Spectrometry By H-GROSS. Principles Of Instrumental Analysis By Holler & Skoog. Instrumental Techniques For Analytical Chemistry By FRAUT SELLER. Organic Spectroscopy & Chromatography By M.YOUNAS
- 38. Amirav, A.Gordin, A. Poliak, M. Alon, T. and Fialkov, A. B. (2008), "Gas Chromatography Mass Spectrometry with Supersonic Molecular Beams". Journal of Mass Spectrometry. Structural Identification Of Organic Compounds With Spectroscopic Techniques By Richard R.Ernst . Introduction To Pharmaceutical Chemical Analysis By Steen Hansen. Mass Spectrometry By E.Constantin and A.Schnell. www.Spectroscopy/Slideshare www. Spectroscopy/Wiki
- 39. Presented to: Respected Sir Irshad & 3rd Prof (Eve) Presentation Given by Members of: ‘‘Real Pharmacist Group (RPG)’’ Made By: Faizan Akram (Faizy) Contributors:- Farhan Amin Zeeshan Khan Rashid Mumtaz Zeeshan Imtiaz Abdul Samad Abdul Muqeet