The document discusses Muhammad Aadil's PhD research presentation on UV-Visible spectroscopy. It introduces spectroscopy, the electromagnetic spectrum, and the principle of UV-Visible spectroscopy involving electronic transitions. It describes the instrumentation including light sources, monochromators, sample holders, and detectors. It discusses Beer-Lambert's law and its use in quantitative analysis. Key terms like chromophores and auxochromes are defined. Applications to analyze the reduction of graphene oxide and formation of metal nanoparticles are mentioned. Common questions about the technique are also listed.

2. Presentation Topic:
Muhammad Aadil
PhD research Scholar
Session (2017-2019)
DEPARTMENT OF CHEMISTRY
The Islamia University of Bahawalpur
UV-Visible Spectroscopy

3. Contents
1- Introduction to Spectroscopy
2-Instrumentation of UV-Visible Spectroscopy
3-Law applied in UV-Visible Spectroscopy
4-Terminology used in UV-Visible spectroscopy
6-Some important Questions
5-Application of UV-Visible spectroscopy in Nano-science

4. What is Spectroscopy?
Source
Matter
EMR
Absorbance
Transmittance
Excited Fluorescence
Scattering
Reflection
UV Spectroscopy: Techniques, instrumentation and data handling
by B.J. Clark, T. Frost, M.A. Russell

5. Matter which show absorption in Visible region look colour

6. Electro magnetic Spectrum
EMR have dual nature but we concern its photon nature in spectroscopy
∆E = hv
∆E = hc/λ
Radiation in UV/Visible region have enough energy to
Cause electronic transition on interacting the substance

7. UV-Visible Spectroscopy Principle
Et= Ee + Ev + Et
Ee > Ev > Et
Electronic transition also
associated with vibrational
transition which are further
associated with vibrational
transition this association
made the UV-Visible
spectrum complex

8. Types of Electronic Transition
C-C
C=C
C-X/N
C=N
Forbidden
Forbidden

9. Instrumentation of UV-Visible Spectroscopy
1-Source
2-Monochromator
3-Sample holder
4-Detector
(W & Deuterium Lamp) W- best for Visible while Deuterium for UV lights
Diffraction grating or Prism
Plastic ,Glass and Quartz
Photomultiplier or Photodiode

10. Beer-Lambert law
This law made UV/Visible spectroscopy useful for quantitative analysis.
A = log Iₒ/I = ε b C
Position of λmax and molar absorption(єmax) are informative

11. Terminology used in UV-Visible Spectroscopy
1- Chromophore (Colour bearing)
A unsaturated group in a molecule which absorb b/w 200-800nm
for electronic transition. Example: N=O, C=C,C=O,S=O, etc.
Conjugation of Chromophore group shift absorption toward
Visible region.

12. Saturated group with non-bonding e that shift the λmax of
Chromophore Example.OH,NH2,CH3
2- Auxochrome

13. Conformation of Formation of rGO from GO
Green synthesis of graphene and its cytotoxic effects in human breast cancer cells by Sangiliyandi Gurunathan
Jae Woong Han,Vasuki Eppakayala and Jin-Hoi Kim
The π-π* transition in GO
give λmax at 230nm. The
Reduction of GO to rGO
cause restoration of C=C
conjugation structure so
λmax shifting to 265nm.
Application of UV-Visible in Nanoscience

14. Spectroscopic investigation on graphe ne-copper nanocomposites with strong UV emission and highcatalytic activity
Formation of Nanocomposite
with Cu nanoparticles cause
hypochromic effect and
Hypsochromic effect.
Composite Formation

15. UV/VIS/IR SPECTROSCOPY ANALYSIS OF NANOPARTICLES
Aggregation of silver nanoparticles cause
decrease in primary peak and increase in
red shifting.
To check aggregation of nanopartilces

16. To Check Stability of Nanopartilces

17. Particle size estimation

18. Common Questions about UV-Visible spectroscopy
1
2
3
4
5
What is the importance of blank in UV-Visible measurements?
Why spectrum is complex in UV-Visible Spectroscopy ?
Why we use UV-Visible Spectroscopy combined?
Why UV-Visible Spectroscopy called electronic spectroscopy?
Why sample in solution form used in UV-Visible Spectroscopy?