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Atomic Emission Spectroscopy

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Presentation on theme: "Atomic Emission Spectroscopy"— Presentation transcript:

1 Atomic Emission Spectroscopy
Emission sources Applications Samples AES operates by exciting elements Rapid relaxation accompanied by emission of UV or visible light Properties Low interelement interference Excitation for wide range of elements under same conditions High temperatures

2 Sources Plasma source Ar plasma generally used High temperatures
Inductively coupled plasma (ICP) Direct current plasma (DCP) Microwave induced plasma (MIP) ICP and DCP are main sources

3 ICP source ICP torch components Ar gas 5-20 L/min 3 quartz tubes
RF source 0.5-2 kW 27 or 41 MHz Ionization initiated by Tesla coil Ions and e- interact with magnetic field Flow and heating Quartz cooling by Ar

4 Sample introduction Samples in Ar in torch center
Nebulizers used for liquid samples Cross flow of Ar Fine droplets carried by gas into plasma Ultrasonic method can also be used Electrothermal vaporization Ablation

5 Electrothermal vaporization

6 Plasma Characteristics
Large temperature variation Spectra collected mm above coil Free from Ar Ar is chemically inert No oxide formation Little reabsorption

7 Direct Current Plasma 3 electrodes 2 graphite anode
Ar flows from anode to cathode Contact between anode and cathode K to K

8 Spectrometers Most spectrometer from 170 nm to 800 nm 3 basic types
Sequential Simultaneous multichannel Fourier transform Move from one element line to the next Different components for UV and visible

9 Spectrometers Multichannel
Simultaneous collection of different wavelengths Requires more detectors CCD or PMT


11 Samples Dissolved samples
Introduction and retention of samples can cause errors Wide variety of elements Most elements have several emission lines Calibration normally linear Self-absorption can limit linearity

12 Elements detected by AES

13 ICP-AES data

14 Calibration curve

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