AES and Various sources spectroscop.pptx

Spectroscopy topic

1. Atomic Asorption Spectroscopy

2. Atomic Emission Spectroscopy

3. Inductive Coupled Plasma Atomic Emission Spectroscopy

4. Inductively coupled plasma Inductively coupled plasma (ICP) is a type of plasma used in analytical techniques for the elemental analysis of samples, particularly for measuring trace concentrations of metals.  It involves creating a plasma by applying a high-frequency electromagnetic field to a flowing gas, typically argon.  This plasma is then used to excite and ionize the sample, allowing for the detection and quantification of different elements.  Argon plasma is defined as an ionized gas composed of argon atoms that have been ionized to create a macroscopically neutral mixture of positive and negative particles, typically generated in a torch using a high-frequency field to sustain the ionization process.

5. Inductively coupled plasma atomic emission spectroscopy  (ICP-OES or ICP-AES) is an analytical spectroscopic technique that relies on optical emission for analysis and gives information about how much of certain elements are in a sample. It is widely used to analyze liquid samples as well as substances that are easily dissolved or digested into liquid form. Since atoms and ions can absorb energy, the ICP-OES principle makes use of this property to shift electrons from their ground state to an excited state. It depends on those excited atoms emitting light at particular wavelengths as they undergo a transition to low energy levels. In layman’s terms, an electron produces light of a specific wavelength as it undergoes transitions from a higher energy level to a lower energy level, typically the ground state. The wavelength of the light emitted varies depending on the type of atom or ion (i.e., whatever element it is) and the energy levels the electron is moving between .

6. Interferences in ICP-OES Some of the commonly observed interferences in  Inductively coupled plasma atomic emission spectroscopy  (ICP-OES/ICP-AES) are: Spectral Interference:  It results from the crossing over of a spectral line from a different element or from background emission from ongoing or recombination processes. Either eliminating background emissions derived from observations near the analyte wavelength peak or inter-elemental correction can be used to eliminate this interference. Chemical Interferences : Such interferences are highly dependent on matrix type and specific analyte elements. Physical Interferences:  The factors like surface tension, viscosity, organic solvents, etc, cause interferences, and can be removed by use of the internal standard.

7. Advantages of Inductively coupled plasma atomic emission spectroscopy Some of the major advantages of  inductively coupled plasma atomic emission spectroscopy  are: Good sensitivity even at low concentration Highly specific Simultaneous multi-elemental analysis Identification of metalloids. Samples in either liquid or solid state can be analyzed

8. Applications of Inductively coupled plasma atomic emission spectroscopy It is an extremely complicated approach for the examination of several heavy metals, metalloids, and even non-metals (at ppm to ppb level) in a wide range of materials that are derived from various sources. This technique possesses greater applications in biological, chemical, and environmental sciences. Thus, some of the major applications of inductively coupled plasma atomic emission spectroscopy are

9. For the determination of   arsenic in food, and trace elements bound to proteins. ICP-AES techniques can be employed for the analysis of agricultural products and foods. For the clinical analysis of metals in biological fluids (blood, urine) eg. Al in blood, Cu in brain tissue, and Se in the liver. Environmental analysis of trace metals and other elements in waters, soils, plants, composts, and sludges. In Forensic science; gunshot powder residue analysis, toxicological examination, and so on. Trace metal analysis in raw materials. Inductively coupled plasma atomic emission spectroscopy is also used for motor oil analysis.

10. In Atomic Emission Spectroscopy (AES), an arc refers to a type of excitation source used to generate light from a sample.  It involves creating an electrical discharge, or arc, between two electrodes, which heats the sample material to a high temperature, causing its atoms to emit light.  This emitted light is then analyzed to identify and quantify the elements present in the sample.  Atomic Emission Spectroscopy

11. Arc Generation: The high voltage initiates a discharge (an arc) between the electrodes.  The arc is sustained by a continuous current flow between the electrodes, typically in the range of 2-30 amps.  The arc provides the energy to excite atoms in the sample.  3 . Excitation and Emission: Atoms in the sample absorb energy from the arc, causing their electrons to jump to higher energy levels. These excited atoms are unstable and quickly return to their ground state, releasing the excess energy as light. The emitted light has specific wavelengths that are unique to each element, acting as a "fingerprint". 

12. What is an Arc? In AES, an arc is a sustained electrical discharge between two electrodes.  The high temperature of the arc (typically thousands of degrees Celsius) causes the sample to vaporize, atomize, and excite its constituent atoms.  These excited atoms then return to their ground state, releasing energy in the form of light at specific wavelengths characteristic of the elements present. 

13. Arc emission spectroscopy is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted when a sample is subjected to an electrical arc or spark.  This light, composed of characteristic wavelengths for each element, is then analyzed to identify and quantify the elements present in the sample Arc or Spark Atomic Emission Spectroscopy Excitation: A high-voltage electrical discharge (either an arc or a spark) is passed through the sample. This energy excites the atoms in the sample, causing electrons to jump to higher energy levels.

14. Emission:  When these excited electrons return to their ground state, they release the excess energy as light at specific wavelengths. Each element emits a unique set of wavelengths, acting as a fingerprint for identification . Analysis: The emitted light is directed into a spectrometer, which separates the light into its constituent wavelengths (a spectrum).  Detectors measure the intensity of light at each wavelength, which is directly proportional to the concentration of the corresponding element in the sample . 

15.  Applications: Arc spark OES is widely used in the metal industry for quality control, material analysis, and process monitoring.  It can analyze a wide range of metals and alloys, including steel, aluminum, copper, and others.  The technique is known for its speed, accuracy, and ability to analyze a variety of elements simultaneously. 

16. Key features of Arc Spark OES: Speed:  Analysis can be performed rapidly, often in seconds, making it suitable for quality control in manufacturing.  Accuracy:  Provides precise quantitative data on elemental composition.  Versatility:  Can analyze a wide range of materials and elements.  Sample Preparation:  Requires relatively simple sample preparation, often involving grinding or polishing the surface.  Matrix Effects:  The technique is matrix-dependent, meaning the presence of other elements can affect the results. Calibration with reference materials is crucial. 

17. Types of Arc/Spark OES: Arc OES :  Uses a continuous electrical arc to vaporize and excite the sample.  Spark OES :  Uses a pulsed electrical spark.  Arc/Spark OES :  Combines both arc and spark excitation for enhanced analysis. 

18. How do IR and Raman spectroscopy differ in terms of the type of molecular vibrations they probe?   What is the principle behind UV-Vis spectroscopy, and what types of electronic transitions are typically observed?   Explain how the Beer-Lambert Law relates absorbance to concentration and path length in UV-Vis spectroscopy.   What are the key components of a UV-Vis spectrophotometer, and what is the role of each component?   How can IR and Raman spectroscopy be used to identify functional groups in a molecule?  

19. A sample shows a strong absorbance peak at 260 nm in UV-Vis spectroscopy. What functional groups might be present in the molecule?   How would you differentiate between ethylbenzene and styrene using UV-Vis spectroscopy?   A compound exhibits a broad absorption band in the UV-Vis spectrum. What factors could contribute to this broadening?   How can you use IR spectroscopy to distinguish between a ketone and an aldehyde?   What are some limitations of using UV-Vis spectroscopy for quantitative analysis?  

20. Why do atomic spectra consist of discrete lines, while molecular spectra are often broad and continuous?   What does it mean when a UV-Vis spectrum shows a hypsochromic shift?   How can you use Raman spectroscopy to determine the crystallinity of a sample?   What are some common sources of error in IR spectroscopy measurements?   How can you use UV-Vis spectroscopy to determine the concentration of a nanoparticle solution?