Recent Advances and Developments in Atomic Emission Spectroscopy Atomic emission spectroscopy is used for elemental analysis and has advanced with the introduction of non-combustion plasma sources like inductively coupled plasma. It works by exciting sample atoms in a heat source, causing electron transitions that emit photons of element-specific wavelengths. Modern instruments detect these photons through optical systems and can analyze solids using laser or spark ablation followed by plasma excitation. Applications include analysis of metals in pharmaceuticals, soils, alloys, and biological or environmental samples. The document reviews excitation sources, sample introduction methods, optical and detection components, and applications across various fields.

1. Recent Advances and Developments in
Atomic Emission Spectroscopy
DIGITAL ASSIGNMENT-1
Course Code: BST5009
Course Title: Analytical Techniques in Biotechnology
Presented By:
Shraddha Sharma (18MSB0031)
Sheshathri P (18MSB0006)
Shivaani Srinivas (18MSB0047)
Justin Solomon (18MSB0083)
Guided By:
Dr. Podili Koteswaraiah
Assistant Professor (Sr.)
SBST
Vellore Institute of Technology

2. INTRODUCTION

3. 1.Used as standard method for the metal analysis
2.In atomic emission small part of sample is vaporized
from free atom that attain energy from excitation
3.This result in transition from lower to higher energy
state
4.On returning back emit a photon of radiation

4. EMISSION SOURCE – ATOMIC EMISSION
SPECTROSCOPY

5. Ancient: atomic emission was only based on
flame, arc or spark excitation sources
Modern era: advancement is made by the
introduction of non combustion plasma sources

6. Principle of Atomic Emission Spectroscopy and
Schematic Diagram of Instrumentation

7. The electrons of an atom moves from higher
energy level to lower energy level, they emit
extra amount of energy in the form of light
which consist of photons
PRINCIPLE
Mirabella, Francis M., ed. Modern techniques in applied molecular spectroscopy. Vol. 14. John Wiley & Sons, 1998.

9. Sources of Emission

10. Atomic Emission Spectroscopy unlike AAS uses very high
temperatures of atomization sources to excite atoms
The sources include-
1. Plasma
2. Arcs
3. Sparks and
4. Flame
Broekaert, J. A. C. "Atomic emission spectroscopy instrumentation." Spectrochimica Acta 37 (1982): 727.

11. Emission Techniques
Type Method of Atomization Radiation Source
Arc sample heated in an electric arc
(4000-5000oC)
sample
Spark Sample Excited in a high voltage
spark
sample
Flame Sample Solution aspirated into a
flame(1700-3200oC)
sample
Argon Plasma Sample heated in an argon
plasma(4000-6000oC)
sample
Broekaert, J. A. C. "Atomic emission spectroscopy instrumentation." Spectrochimica Acta 37 (1982): 727.

12. FLAME SOURCES
Sample solution is sprayed into a
flame as mist or aerosol
Sample is vaporized in flame
Sample is then atomized by heat
+ action of reducing gas
atoms are excited into higher
electronic states by the heat, and
as they revert to the ground
they emit photons, which are
measured by the detector
Broekaert, J. A. C. "Atomic emission spectroscopy instrumentation." Spectrochimica Acta 37 (1982): 727.

13. Plasma Sources
Plasma- “A homogenous mixture of gaseous atoms, ions and electrons at very high
temperature”
Three types of plasma sources used
1.Direct plasma
2.Microwave induced plasma
3. Inductively coupled plasma
Griem, Hans R. Principles of plasma spectroscopy. Vol. 2. Cambridge University Press, 2005.

14. Direct Plasma
• The DCP is composed of three electrodes arranged in an inverted Y configuration.
• A tungsten cathode resides at the top arm of the inverted Y.
• The lower two arms are occupied by two graphite anodes.
• Argon flows from the two anode blocks and plasma is obtained by momentarily bringing the
cathode in contact with the anodes.
• Argon ionizes and a high current passes through the cathode and anodes.
• The temperature here is about 5000 oc
Griem, Hans R. Principles of plasma spectroscopy. Vol. 2. Cambridge University Press, 2005.

15. Direct current plasma is created by
the electronic release of the two
electrodes
The samples are placed on an
electrode
In the technique solid samples are
placed near the discharge to
encourage the emission of the
sample by the converted gas
atoms
Griem, Hans R. Principles of plasma spectroscopy. Vol. 2. Cambridge University Press, 2005.

16. Advantages of DCP
-Less argon consumption.
- Simpler instrumental requirements
- less spectral line interference
Disadvantages of DCP
-DCP sources usually have fewer lines than ICP sources, require less argon/hour, and
lower sensitivities than ICP sources
-In addition, the graphite electrodes tend to decay with continuous use and should thus
frequently exchanged

17. Microwave Induced Plasma(MIP)
• MIP operates with a low helium flow rate
• Suitable for the determination of halides and other nonmetals
• Plasma torch consists of concentric copper tubes
• The carrier gas and aerosol enter the inner tube while the outer tube serves as the
microwave cavity
• The plasma is formed at top of the torch and extends out like a flame
• Allows the introduction of wet aerosols at lower power
Griem, Hans R. Principles of plasma spectroscopy. Vol. 2. Cambridge University Press, 2005.

19. Inductively Coupled Plasma
• ICP sources have brought about a revolution in multielement analysis. Icps are generated from
radiofrequency (RF) magnetic fields induced by a water- or air-cooled copper coil looped around a quartz
tube.
• Icp source is the icp torch
• Ionization of flowing argon by spark
• Ionized argon interacts with strong magnetic field
• Very high temperature obtained that gives very high resistance
• Top of quartz tube should be cooled by passing argon tangentially around the walls of the tube
Penner, Michael H. "Basic principles of spectroscopy." Food analysis. Springer, Cham, 2017. 79-88.

21. Discharge Sources(Arcs and Sparks)
Arc source
The first discharge sources produced direct current (DC) arcs by electrically heating the sample in an
electrode cup and vaporizing the analytes into a low-voltage, high-current discharge. The temperature of
the arc plasma varies from 4000 to 5000K
Spark source
Spark sources produce lower average temperature than arcs, but the local temperature can be as high as
40000K.An AC potential in the order of 10-50 KV is discharged through a capacitor which is charged and
discharged through the graphite electrodes about 120 times resulting in a discharge current of about 1000
A

22. Arc
One is a Graphite Electrode and the other is a
sample electrode
Transformer
Potential
Source
Capacitor: Charged and discharge periodically in the
electrodes rapidly giving spark (1000 A)

23. Characteristics of Arc Sources
1.Typical temperatures between 4000-5000 oc are high enough to cause atomization and excitation
of sample and electrode materials
2.Usually, cyanogens compounds are formed due to reaction of graphite electrodes with atmospheric
nitrogen
Emission bands from cyanogens compounds occur in the region from 350-420 nm
Disadvantage:
Several elements have their most sensitive lines in this same region which limits the technique.
Overcome:
Use of controlled atmosphere around the arc (using CO2, helium, or argon) very much decreases the
effect of cyanogens emission

24. Why we use Carbon???(Graphite)
1. It is conductive
2. It can be obtained in a very pure state
3. Easily available and cheap
4. Thermally stable and inert
5. Carbon has few emission lines
6. Easily shaped

26. INSTRUMENTATION-ATOMIC EMISSION SPECTROSCOPY
Emission source -
produce spectrum
Optical system –
scatters the spectrum
Detector – to measure
the emitted lines
Three major parts of atomic emission spectroscopy:

27. SAMPLE INTRODUCTION – ATOMIC
EMISSION SPECTROMETER
Liquids
 Form an aerosol (<5 µ droplet size) of the liquid sample
 Eliminate larger droplets
 The use of liquids facilitates automatic sampling:
Gases
 May use gasses directly or indirectly, e.g., form hydrides
Solids
 May use slurries (if 95% of particles <5 µ)
 May use spark ablation or laser ablation to generate a small metal vapor
Mirabella, Francis M., ed. Modern techniques in applied molecular spectroscopy. Vol. 14. John Wiley & Sons, 1998.

28. VIEWING POSITION
 Done by Spectrometer - side-on or end-on
 These viewing positions are called radial and axial
viewing
 radial viewing - normal analysis and complex materials
 axial viewing - low detection limits in simpler materials

29. ANALYSIS OF SOLIDS IN PLASMA
SOURCES
Spark ablation
 conducting samples are vaporized with an
electrical discharge
 nonconducting samples are first modified by
mixing with copper or carbon powder
 The dry aerosol is carried by an argon stream
into the plasma
 Large particles can be eliminated using traps,
as long as internal references are available.
Laser ablation
 used as a microchemical sampling procedure
for localized determinations
 A pulsed neodymium–yttrium aluminium garnet
(Nd–YAG) laser is used to ablate material from
solid sample
 Refractory materials and geological samples
can be analyzed for trace and major elements
 Powdered samples can be pelleted under high
pressure for bulk analysis

30. NEBULISER – ATOMIC EMISSION
SPECTROSCOPY

32. NEBULISER – ATOMIC EMISSION SPECTROSCOPY
Pneumatic nebulizer:
• Aerosol is formed by shattering effect of a high
velocity jet of gas
• Most commonly used nebulizer – meinhard glass
concentric nebulizer, sensitive to clogging
• Sample is introduced along a narrow capillary tube
located within a larger glass or quartz tube
• Particles with high salt concentration should be
avoided
(Buddiga, Praveen, 2011)

33. NEBULIZER – ATOMIC EMISSION
SPECTROSCOPY
ULTRASONIC NEBULIZER:
 Uses ultrasound waves to boil solution flowing across disc
 Ultrasonic nebulizers offer enhanced sensitivity in detection limits by using a vibrating piezoelectric
transducer to set up standing waves in the liquid to produce uniformly sized droplets
 The efficiency of nebulization is so high that the solvent loading of the aerosol needs to be reduced by
thermal desolvation, otherwise cooling of the plasma takes place
Mirabella, Francis M., ed. Modern techniques in applied molecular spectroscopy. Vol. 14. John Wiley & Sons, 1998.

34. TYPES OF PNEUMATIC
NEBULIZERS
• consist of a capillary tube that directs
a stream of argon gas at 901 to the
sample delivery tube, creating an
aerosol due to its shearing effect
over the sample tube
• these nebulizers are designed for
general-purpose use, although they
are less prone to blockage where the
sample has a high salt concentration
concentric tube cross flow

35. TYPES OF PNEUMATIC
NEBULIZERS
• The liquid sample flows over a smooth
surface containing a small orifice,
through which argon flows at a high
velocity, shearing the liquid into tiny
droplets
• This device is not susceptible to
clogging and can handle viscous
solutions and suspensions
BABINGTON
NEBULIZER

36. Types of pneumatic nebulizers
ANOTHER TYPE OF CONCENTRIC TUBE CROSS FLOW

37. Types of pneumatic nebulizers
FITTER DISK
NEBULIZER

38. OPTICAL SYSTEM – ATOMIC
EMISSION SPECTROSCOPY
Once the sample has been introduced into the
emission source, atomized, and excited, the emitted
photons are diffracted by an optical system consisting
of slits, mirrors, and gratings, which focus the spectral
lines onto a detector

39. GRATINGS
Maxwell, 2009

40. GRATINGS
Ruled gratings:
 The grating pattern created in this way is greatly superior to those produced
mechanically, being much more accurate, having higher linearity, and being free
from imperfections and distortions that can give rise to ghosts and stray light
Echelle grating:
 designed to operate in multiple orders to produce high-resolution spectra
 ruled at 30– 300 grooves per millimeter by ion bombardment, and are
frequently in the range of 30–120 orders
Gardecki, J. A., and M. Maroncelli. "Set of secondary emission standards for calibration of the spectral responsivity in emission spectroscopy." Applied Spectroscopy 52.9 (1998):
1179-1189.

41. MONOCHROMATORS
• Measures a single wavelength, but
can be scanned through a wide
wavelength range
• Polychromatic light passes through
an entrance slit and is dispersed by
diffraction gratings
• Sequential mode, element
determinations being performed
one after the other
• Two designs: Czerny–Turner and
echelle
David Harvey, 2016

42. MONOCHROMATORS
Czerny–Turner monochromators
 Two mirrors are used to reflect and focus
the polychromatic and diffracted beams
 Wavelengths are selected by using a
computer to rotate the grating in various
ways
Echelle monochromators
 These are high-resolution instruments
that readily achieve resolutions of 5 pm in
contrast to the 10–20pm that is normal
for conventional sequential instruments
 Because the spectra are recorded one
above the other, such instruments can be
very compact

43. MONOCHROMATORS
Czerny–Turner monochromator, Welz B and Sperling M (1999)

44. DETECTORS - ATOMIC EMISSION
SPECTROSCOPY
Photomultiplier Tubes
Photons emerging from the exit slits of the spectrophotometer are detected by one of two types of
device:
 Charge-injection devices (CIDs)
can be used in combination with an echelle spectrometer to produce a flexible detection system
 Charge coupled devices (CCDs)
the high-energy echelle spectrometer utilizes two detector focal planes and two cross-dispersers
Lajunen, Lauri. Spectrochemical analysis by atomic absorption and emission. Royal Society of Chemistry, 2007.

45. DETECTORS
Photodiode arrays (PDAs)
Radiation from the plasma is pre-dispersed and transmitted through an optical
mask prior to dispersion by an echelle grating onto a PDA

46. COMPARISON BETWEEN ATOMIC
ABSORPTION AND EMISSION SPECTROSCOPY
ABSORPTION
 Measure trace metal
concentration in complex
matrices
 Depends upon ground state
atoms
 Account wavelengths absorbed
by a substance
EMISSION
 Measure trace metal
concentration in complex
matrices
 Depends upon the excited atoms
 Account wavelengths emitted by
a substances
Winefordner, J. D., et al. "A Critical Comparison of Atomic Emission, Atomic Absorption, and Atomic Fluorescence Flame Spectrometry." (1970): 233-272.

47. APPLICATIONS AND
DEVELOPMENTS

48. It is used for rapid analysis of multicomponent pharmaceutical tablet
It is used for elemental analysis
It is used in identification and determination of metals in traces amount
It is used for the determination of mineral composition of igneous and
metamorphic rocks
It is used for routine analysis of wear metals in lubricating oils
And for the analysis of sodium, potassium and lithium
Silicon is recognized as essential trace element participating in normal body
metabolism
Evaluation of platinum in body tissues and fluids after administration of platinum
containing anticancer drug

49. Forensic Sciences
Crime scene soil analysis.
Metallurgy
Analysis of trace elements in stainless steel.
Environmental science
Waste water analysis, determination of pollutant metals in variety of matrices.
Industry
Presence of metals like Cu, Fe, Ni, and Si in lubricating oils or gasoline at tracer concentration.
Traces of metals like Ca, Cu, Fe, Mn, Mg, P, K and Zn in beer or wine; determination of trace
elements in polymers, evaluation of catalysts, and so on.

50. Agricultural science
Analysis of agricultural products and foods besides soil
analysis.
Health sciences
Determination of Al in blood, Cu in brain tissue, Se in liver,
Na in breast milk.
Direct determination of Ca, Fe, Cu, Mg, Na and K in serum samples.
Geological sciences
Presence of lanthanides and other elements in rock samples.

55. ELEMENTS BY ICP-AES
Different elements have different emission intensities.
Alkalis (Na, K, Rb, Cs) are weakly emitting.
Alkaline Earths (Be, Mg, Ca, Sr, Ba ) are strongly emitting (sensitive to low con)

56. The ICP-AES technique is versatile tool in the hands of analytical chemists.
As many as 60 elements can be determined by it in a wide range of
analyte samples such as rocks, minerals, soil , air, water, agriculture,
forestry ecology, food analysis, etc. Therefore it has become an
indispensable technique. Some of the important analytical applications in
different areas are given below, you would learn about the applications in
detail in the next unit.

57. REFERENCES
• Evans, E. Hywel, et al. "Atomic spectrometry updates: review of advances in atomic
spectrometry and related techniques." Journal of analytical atomic spectrometry 29.5
(2014): 773-794
• Taylor, andrew, et al. "Atomic spectrometry update: review of advances in the analysis of
clinical and biological materials, foods and beverages." Journal of analytical atomic
spectrometry 29.3 (2014): 386-426
• Ozbek, nil, and suleyman akman. "Microwave plasma atomic emission spectrometric
determination of ca, K and mg in various cheese varieties." Food chemistry 192 (2016):
295-298
• Soo, michael, et al. "Emission and laser absorption spectroscopy of flat flames in aluminum
suspensions." Combustion and flame 180 (2017): 230-238
• Stecher, theodore p., Et al. "The ultraviolet imaging telescope-design and performance." The
astrophysical journal 395 (1992): L1-L4