The document discusses electromagnetic radiation and ultraviolet spectroscopy, explaining that UV spectroscopy involves measuring the absorption of UV or visible light, which provides information about electronic transitions in molecules. It describes the components of a UV spectrometer and the principles of absorption spectroscopy. Various applications of UV spectroscopy in forensic science are also outlined, such as identifying illegal substances or determining the number of inks in questioned documents.
Atomic Absorption Spectroscopy is a very common technique for detecting metals and metalloids in samples.
It is very reliable and simple to use.
It can analyze over 62 elements.
It also measures the concentration of metals in the sample.
Atomic Absorption Spectroscopy is a very common technique for detecting metals and metalloids in samples.
It is very reliable and simple to use.
It can analyze over 62 elements.
It also measures the concentration of metals in the sample.
describes the complete history, mechanisms, instrumentation(jablonski diagram), types, comparision and factors affecting, applications of fluorescence and phosphorescence and describes about quenching and stokes shift.
Introduction to Spectroscopy,
Introduction to UV, electronic transitions, terminology, chromophore, Auxochrome, Examples and Applications.
Introduction to IR, Fundamental vibrations, Types of Vibrations, Factors affecting the vibrational freaquencies, Group frequencies, examples and applications.
Infrared spectroscopy (IR spectroscopy) is the spectroscopy that deals with the infrared
region of the electromagnetic spectrum, that is light with a longer wavelength and
lower frequency than visible light.
Infrared Spectroscopy is the analysis of infrared light interacting with a molecule.
Introduction,Instrumentation, Classification of electronic transitions, Substituent and solvent effects, Classification of electronic transitions
Substituent and solvent effects
Applications of UV Spectroscopy
UV spectral study of alkenes
UV spectral study of poylenes
UV spectral study of α, β-unsaturated carbonyl
UV spectral study of Aromatic compounds
Empirical rules for calculating λmax.
Applications of UV Spectroscopy, Empirical rules for calculating λmax.
Unlike a spectrometer (which is any instrument that can measure the
properties of light over a range of wavelengths), a spectrophotometer
measures only the intensity of light as a function of its wavelength.
The detailed information of UV Visible Spectroscopy, it includes the information regarding electronic transitions, Electromagnetic radiations, Various shifts.
describes the complete history, mechanisms, instrumentation(jablonski diagram), types, comparision and factors affecting, applications of fluorescence and phosphorescence and describes about quenching and stokes shift.
Introduction to Spectroscopy,
Introduction to UV, electronic transitions, terminology, chromophore, Auxochrome, Examples and Applications.
Introduction to IR, Fundamental vibrations, Types of Vibrations, Factors affecting the vibrational freaquencies, Group frequencies, examples and applications.
Infrared spectroscopy (IR spectroscopy) is the spectroscopy that deals with the infrared
region of the electromagnetic spectrum, that is light with a longer wavelength and
lower frequency than visible light.
Infrared Spectroscopy is the analysis of infrared light interacting with a molecule.
Introduction,Instrumentation, Classification of electronic transitions, Substituent and solvent effects, Classification of electronic transitions
Substituent and solvent effects
Applications of UV Spectroscopy
UV spectral study of alkenes
UV spectral study of poylenes
UV spectral study of α, β-unsaturated carbonyl
UV spectral study of Aromatic compounds
Empirical rules for calculating λmax.
Applications of UV Spectroscopy, Empirical rules for calculating λmax.
Unlike a spectrometer (which is any instrument that can measure the
properties of light over a range of wavelengths), a spectrophotometer
measures only the intensity of light as a function of its wavelength.
The detailed information of UV Visible Spectroscopy, it includes the information regarding electronic transitions, Electromagnetic radiations, Various shifts.
UV - Visible Spectroscopy detailed information is included .The Spectroscopy study provide the information and the absorbance as well the concentration of the drugs is studied.
spectroscopy, classification of spectroscopy, history, UV-VIS spectrophotometer, principle, beer lambert law instrumentation, detector, single beam, double beam in time, double beam in space, application, merits, and demerits
Spectrophotometer instrumentation & working Sabahat Ali
Spectrophotometric analysis is a technique to measure the concentration of solute solution by measuring the amount of light absorbed by solution.
Absorption can be calculated in terms of transmittance by using Beer's Lambert law.
Spectroscopy is a method which measures the interaction of matter with electromagnetic radiation. it reveals different properties of substances such as absorbance, composition and interaction with other matter
http://www.redicals.com
The spectrophotometer technique is to measures light intensity as a function of wavelength.
• Measures the light that passes through a liquid sample
• Spectrophotometer gives readings in Percent Transmittance (%T) and in Absorbance (A)
details about uv-visible spectroscopy. intoduction to uv-visible spectroscopy with principle,
instrumentation, application, beers lamberts law , detectors. helps to know details about uv-visible spectroscopy. complete notes of uv-visible spectroscopy.
Spectroscopy using spectrophotometers of different types like: U.V, Mass Spectrophotometer, absorption , Emission, Nuclear magnetic resonance and X-rays Spectrophotometer
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
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We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
How to Make a Field invisible in Odoo 17Celine George
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Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
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3. It is the branch of science that deals
with the study of interaction of matter
with light.
or
It is the branch of science that deals
with the study of interaction of
electromagnetic radiation with the
matter.
5. Electromagnetic radiation are different forms
of energy which have a dual character; they
have the properties of both wave and particle.
They are called electromagnetic radiations
because they consist of oscillating electric and
magnetic field which are perpendicular to
each other and perpendicular to the direction
of motion of the radiations.
Electromagnetic radiation consist of discrete
packages of energy which are called photons
6.
7. The energy of these radiation is
inversely proportional to their wavelength
and directly proportional to their
frequency.
These radiation do not require any
physical medium and can be transmitted
through empty space.
All types of electromagnetic radiations
travel through space with the same
velocity which is nearly same as the
speed of light.
8. Wavelength It is the distance between
two adjacent crest or trough in a particular
wave. It is denoted by the symbol λ
Usually expressed in meters, micrometers
nanometers and angstrom.
Frequency It is the number of waves
which passes across a point in one
second.
Generally expressed as hertz
9.
10. The arrangement of entire range of
electromagnetic radiations in
increasing order of their wavelengths
or decreasing order of their
frequencies is known as
electromagnetic radiation.
11.
12. The principle is based on the measurement
of spectrum of a sample containing atoms/
molecules.
Spectrum is a graph of intensity of absorbed
or emitted radiation by sample versus
frequency or wavelength.
Spectrometer is a device design to measure
the spectrum of a compound.
13. Absorption spectroscopy- An analytical
technique which concerns with the
measurement of absorption of
electromagnetic radiation.
E.g. UV(185-400nmm)/visible(400-800)
spectroscopy, IR spectroscopy.
14. Emission spectroscopy is a analytical
technique in which emission (of a radiation
or a particle ) is dispersed according to some
property of the emission and the amount of
dispersion is measured.
E.g. mass spectroscopy
.
15. When a beam of electromagnetic radiation is
passed through a substance, the radiation
may be either absorbed or transmitted
depending upon the wavelenth of the
radiation and molecular structure of the
substance.
Absorption of radiation would generally
increase in the energy of the molecule; the
increase in the energy may lead to electronic
excitation whereby electrons are raised to
higher energy level. Alternatively it may
bring about increase in the vibrational and
rotational energy of the level.
16.
17. Ultraviolet spectroscopy involves the
measurement of absorption light in the
visible and ultraviolet region by a substance.
Absorption of light involves transition from
one electronic energy level to another within
a molecule , so also known as electronic
spectroscopy
18.
19. A uv spectrometer consist of the following
parts:
A source of radiation which emits all
wavelengths of UV. The common used source of
light in the uv region are hydrogen or deuterium
discharge lamp while a tungsten filament is used
for producing visible light.
Monochromator – which separates the radiation
into two individual wavelength. The single
wavelength of radiation is split into two beams
one of which passes through the sample and
other passes through the reference sample.
20. Detector- continuously measures the
intensity ratio of the beams transmitted
through the sample and the solvent
respectively.
Recorder- Automatically records the
absorption of light at each wavelength as a
graph
21.
22.
23. Absorption of visible and uv light produces
change in electronic states in the molecule
associated with excitation of a electron
from lower to higher energy level.
Each electronic level in a molecule is
associated with no of vibrational sub level
Each vibrational level in turn are associated
with no. of rotational sub-levels.
24.
25. Optical system- spectrometers are
instrument that provide information about
the intensity of light absorbed or
transmitted as a function of wavelength.
Both single and double beam optical
system are used in molecular absorption
spectroscopy.
26.
27. Double beam system is used extensively for
spectroscopic studies. The individual
component of system have same function as
in single beam system, important difference
is radiation from source is split into two
beams of approximately equal intensity using
a beam splitter.
The intensity of the two beams after passing
through the cells are then compared.
28.
29. Radiation source for molecular absorptions
must produce light over a continuum of
wavelengths. Traditionally the two most
common radiation source used for UV
spectroscopy were:
Tungsten lamp
Deuterium lamp
30. Tungsten lamp is similar in functioning to the
ordinary electric light bulb. It contains a
tungsten filament heated electrically to
white light, and generates a continuum
spectrum.
It has two shortcomings:
The intensity of radiation at short
wavelengths is too low; furthermore to
maintain constant intensity, electrical bulb
current to the bulb must be carefully
controlled
31.
32. The deuterium lamp consist of deuterium gas
in a quartz bulb through which there is
electrical discharge. The molecules are
excited electrically and the excited molecule
dissociates emitting UV radiation.
33.
34. A monochromator consist of an dispersion
element, an entrance slit, and an exit slit plus
lenses and mirror for collimating and focusing
the beam of radiation.
The two most common type of dispersion
element are prism and gratings.
Entrance slit allows light from the source to fall
on the dispersion element. The dispersed light
falls on the exit slit of the monochromator. The
function of the slit is to permit only a very
narrow band of light to pass through to the
sample and detector
35. • The purpose of the detector is convert the transmitted
radiant energy into an equivalent amount of electrical
energy .
• Two types of detectors are frequently used :-
1- Photomultiplier tube ( PMT ) :
• Incident light strikes the coated cathode , emitting
electrons .
• The electrons are attracted to a series of anodes , known
as dynodes , each having a
Successively higher positive voltage .
• Theses dynodes are of a material that gives off many
secondary electrons when hit by single electrons .
• Initial electron emission at the cathodes triggers a multiple
cascade of electrons within the PMT itself .
• Because of this amplification , PMT are used in instruments
designed to be extremely sensitive to very low light levels .
• the accumulation of electrons striking the anode produces
a current signal that can be fed into a meter or recorder .
36.
37. Photodiode arrays ( PDA ) :
Are new detectors being used in modern spectrometers.
photodiodes are composed of silicon crystals that are
sensitive to light in the wavelength range 170-1100 nm.
Upon photon absorption by the diode , a current is
generated in the photodiode that is proportional to the
number of photons.
Although photodiodes are not as sensitive as PMT
because of the lack of internal amplification , their
excellent linearity , speed , and small size make them
useful in applications where light levels are adequate .
PDA detectors are available in integrated circuits
containing 256 to 2,048 photodiodes in a linear
arrangement .
Each photodiode responds to a specific wavelength, and
as a result, a complete UV/visible spectrum can be
obtained in less than 1 second .
38. Are most often used to obtain quantitative
information , such as the concentration of a solute in
solution or the absorption coefficient of a
chromophore .
• For fixed-wavelength measurements with a single-
beam instrument, a cuvette containing solvent only is
placed in the sample beam and the instrument is
adjusted to read “Zero” absorbance .
• A matched cuvette containing sample plus solvent is
then placed in the sample chamber and the
absorbance is read directly from the display .
• The adjustment to zero absorbance with only
solvent in the sample chamber allows the operator to
obtain a direct reading of absorbance for the sample
39. Fixed-wavelength measurements using a double-
beam spectrophotometer are made by first
zeroing the instrument with no cuvette in either
the sample or reference holder .
Alternatively , the spectrophotometer can be
balanced by placing matched cuvettes containing
water or solvent in both sample chambers .
Then, a cuvette containing pure solvent is placed
in the reference position and a matched cuvette
containing solvent plus sample is set in the
sample position .
The absorbance reading given by the instrument
is that of the samples; that is, the absorbance
due to solvent is subtracted by the instrument
40. For recording the UV spectrum, the given
compound is generally dissolved in some
suitable solvents which does not absorb light in
the region under examination.
The commonly employed solvents are 95%
ethanol, hexane, and water.
The solution of the compound is placed in a
suitable transparent container which does not
absorb light in the region being studied; a
quartz cell of 1cm path length is generally used
for this purpose.( glass cannot be used since it
absorbs strongly in the ultra violet region)
41. CHROMOPHORE: The term chromophore was
previously used to denote a functional group of
some other structural feature of which gives a color
to compound. For example- Nitro group is a
chromophore because its presence in a compound
gives yellow color to the compound. But these days
the term chromophore is used in a much broader
sense which may be defined as “any group which
exhibit absorption of electromagnetic radiation in a
visible or ultra-visible region “It may or may not
impart any color to the compound. Some of the
important chromophores are: ethylene, acetylene,
carbonyls, acids, esters and nitrile groups etc.
42. AUXOCHROMES: It is a group which itself does not
act as a chromophore but when attached to a
chromophore, it shifts the adsorption towards
longer wavelength along with an increase in the
intensity of absorption. Some commonly known
auxochromic groups are: -OH, -NH2, -OR, -NHR,
and –NR2. For example: When the auxochrome –
NH2 group is attached to benzene ring. Its
absorption change from λ max 225 (ɛmax 203) to
λmax 280 (εmax1430)
43.
44. When absorption maxima (λmax) of a
compound shifts to longer wavelength, it is
known as bathochromic shift or red shift.
The effect is due to presence of an
auxochrome
or by the change of solvent.
e.g. An auxochrome group like –OH, -
OCH3
causes absorption of compound at longer
wavelength.
45. When absorption maxima (λmax) of a
compound shifts to shorter wavelength, it is
known as hypsochromic shift or blue shift.
The effect is due to presence of an group
causes removal of conjugation or by the
change of solvent.
46. • When absorption intensity (ε) of a compound is
increased, it is known as hyperchromic shift.
• If auxochrome introduces to the compound,
the intensity of absorption increases.
Pyridine 2-methyl pyridine
λmax = 257 nm λmax = 260 nm
47. When absorption intensity (ε) of a compound
is
decreased, it is known as hypochromic shift.
Naphthalene 2-methyl naphthalene
ε = 19000 ε = 10250
48.
49. Ultraviolet (UV) light technologies are used for
multiple purposes in forensic investigations,
including authenticating paintings and other fine
art, authenticating signatures,
analyzing questioned documents , illuminating
latent fingerprints at crime scenes and trace
evidence on clothing, analyzing ink stains, and
revealing residual stains of body fluids.
Forensic technicians also use UV light technologies,
such as ultraviolet monochromators or
optical spectroscopy , to detect the presence of
illegal or controlled substances or their residues in
unidentified samples, or to determine how many
types of ink or pens were used in a forged
document.