Analysis Techniques
Prof.Dr. Figen KAYA
LECTURE
• YOU WIL SELECT A REPRESENTATIVE
• SOME LECTURE NOTES AND HANDOUTS WILL BE
PROVIDED
http://www.yarbis.yildiz.edu.tr/fkaya-Duyurular
• ONE MIDTERM EXAMINATIONS
• HOMEWORK ASSIGMENTS
RULES
• ARRIVE TO CLASS ON TIME
• DO NOT READ ANYTHING ELSE (NEWSPAPER)
IN CLASS
• MOBILE PHONES
• ASK QUESTIONS IN ENGLISH
Course Materials
• ASM Handbook Volume 10 Materials Characterization, ISBN
0-87170-007-7
• Materials Characterization; An Introduction to Microscopic
and Specroscopic Methods, Y.Leng, Wiley Publishing ISBN
978-0-470-82298-2
• Chemical Analysis, Modern Instrumentation Methods and
Techniques, F.Rouessac, A.Rouessac, Wiley Publishing, ISBN
978-0-470-85903-2
• Principles of Instrumental Analysis, D.A.Skoog, F.J.Holler,
T.A.Nieman, Saunders College Publishing. ISBN0-03002078-6
• Quantitative Chemical Analysis, D.C.Harris.
W.H.Freeman and Company ISBN:0-7167-4464-3
What is Analysis?
Analysis: What are the constituents of the sample?
Analytical chemistry deals with methods for determining the chemical
composition of samples of matter.
Analysis could be classify into two categories:
1- Qualitative Methods
2- Quantitative Methods
Constituent: A component part of
something (i.e. Composite, cpompound,
mixture etc.)
 Hot water
 Coffee granules
 Sugar
 Milk
 Cream
 Cacao powder
Qualitative Analysis:
The aim of qualitative analysis is a complete,
detailed description.
Qualitative method yield information about the
identitiy of atomic or molecular species or the
functional groups in the sample.
→Which atom/atoms, molecule/molecules are
coming together in the make up of the sample?
Group= Green tokens
(pieces)+
Yellow tokens+
Blue tokens+
Red tokens
Quantitative Analysis
Quantitative Analysis; we classify features, count them,
and even construct more complex statistical models in an
attempt to explain what is observed.
Quantitative method provides numerical information as
to the relative amount of one or more of these
companents.
→How many/ how much grams? volumes? of
atom/atoms or molecule/molecules in the sample
Group= 6 Green tokens (pieces)+
8 Yellow tokens+
6 Blue tokens+
10 Red tokens
Classification of Analytical Methods
1- Classical Methods (Wet Chemical Methods):
The analyses are carried out by seperating the components of
interest (analytes) in a sample by;
*Precipitation, *Extraction*Distillation.
For qualitative analses, the seperated components are
treated with reagents that yielded products that could be
recognised by;
→their colors,
→ their boiling or melting points,
→ their solubilities in a series of solvents,
→their odors,
→ their optical activities,
→their reactive indexes
• Reagent: A substance or compound that is
added to a system in order to bring about a
chemical reaction, or added to see if a
reaction occurs.
Reagent: Cobalt(II)thiocyanate
C2CoN2S2→ Red
After reaction with cocaine
→ turns to Blue
• Blue litmus paper turns red under acidic conditions and red litmus paper
turns blue under basic (i.e. alkaline) conditions.
• hydroxyphenoxazone
For quantitative analyses, the amount of analyte
is determined by gravimetric or by titrimetric
measurements.
• Gravimetric measurement: the mass of the
analyte is determined.
• Titrimetric measurement: The volume or mass
of a standart reagent required to react
completely with the analyte is measured.
Instrumental Methods:
Use of physical properties of analytes such as;
→Conductivity
→electrode potential
→light absorption or emission
→flourescence to analyse quantitative analysis of samples.
Seperating and determining chemical make up of a sample
by machines and devices.
Instrumental Methods:
Instrumental Methods could be classify into 4
different groups:
1) Spectroscopic Methods
2)Electrochemical Methods
3) Cromotographic Methods
4) Thermal Methods
Spectroscopy
• What Is Spectroscopy?
Spectroscopy is a technique that uses the interaction of
energy with a sample to perform an analysis.
Studying the properties of matter through its interaction
with different frequency components of the
electromagnetic spectrum.
Latin: “spectron”—ghost or spirit
Greek: “ σκοπειν ”—to see
Spectrum
With light, you aren’t looking directly at the
molecule—the matter—but its “ghost.”
You observe the light’s interaction with different
degrees of freedom of the molecule.
Each type of spectroscopy—different light
frequency—gives a different picture
X Rays → XRD spectrum.
UV light → UV spectrum
IR (Infra Red) light → IR-Raman spectrum
Electromagnetic wave (radiation) is an energy form that
may be propagated through space and may interact
with atoms and molecules to alter their energy state.
• What is a Spectrum?
The data that is obtained from spectroscopy is
called a spectrum. A spectrum is a plot of the
intensity of energy detected versus the
wavelength (or mass or momentum or
frequency, etc.) of the energy.
Goals:
• Understand how light interacts with matter
and how you can use this to quantitatively
understand your sample.
• Understand spectroscopy the way you
understand other common tools of
measurement like the watch or the ruler.
• See that spectroscopy is a set of tools that you
can put together in different ways to understand
systems → solve chemical problems.
The immediate questions that we
want to address are:
• What does light do to sample?
• How do you produce a spectrum?
• What EXACTLY is a spectrum a measurement
of?
What does a spectrum measure?
Interaction of light with a sample can influence
the sample and/or the light.
Method involves:
(1) excitation and (2) detection.
• Excitation: The activity produced in any
system that is caused by stimulation.
In most spectroscopies, we characterize how a sample
modifies light entering it.
1) Absorption: Change in intensity I of incident
light
Sample attenuates light → transmission T=I/I0
Absorption:
• We measure the absorption of light at
different frequency or wavelength.
2) Emission: Excitation induces emission of light
from the sample
Includes:
• Fluorescence (emission from excited electronic singlet states)
• Phosphorescence (emission from excited electronic triplet states)
• Raman Scattering (light scattering involving vibrational transition) (usually of
different frequency).
3) Optical Rotation: Change of phase of light
incident on sample (rotation of polarization)
What Are Types of Spectroscopy?
There are as many different types of spectroscopy as there are energy
sources!
Here are some examples:
1. Atomic (Optical) Emission Spectroscopy
2. Atomic Absorption Spectroscopy
3. Inductively Coupled Plasma Atomic Emission Spectroscopy
4. UV- Visible Absorption Spectroscopy
5. Infra-Red Spectroscopy (IR/FT-IR)
6. Raman Spectroscopy
7. X Ray Diffraction
8. X Ray Flourescence spectrometry
9. Mass spectrometry
10. X-ray photoelectron spectroscopy (XPS)
11. Auger electron spectroscopy (AES),
Let’s work on describing absorption.
What are the axes?
X-axis: Characterizes the input light in terms of
frequency-wavelength-energy
• Wavelength λ (nm, μm, Å),
• Frequency ν (cycles/sec or s-1 or Hz)
λν= c
• Energy (expressed as eV or as cm-1)
E = hν
λ→Wavelength
υ→frequency
c →Speed of light
Y-axis: Absorption
𝐴 ν =
𝐼
−𝑙𝑜𝑔 =𝜀
𝐼0
ν 𝐶𝐿
(Beer’s Law)
I0 = light intensity incident on the sample
I = light intensity after the sample
ε = molar decadic extinction coefficient
(M−1cm −1 ) – absorption coefficient
c = concentration (M)
L = sample length (cm)
Electromagnetic wave (radiation) is an energy form
that may be propagated through space and may
interact with atoms and molecules to alter their
energy state.
What Information Is Obtained?
A spectrum can be used to obtain information on;
→atomic and molecular energy levels,
→ molecular geometries,
→ chemical bonds,
→ interactions of molecules, and related processes.
Often, spectra are used to identify the
components of a sample (qualitative analysis).
Spectra may also be used to measure the amount
of material in a sample (quantitative analysis).
What Instruments Are Needed?
There are several instruments that are used to
perform a spectroscopic analysis.
In simplest terms, spectroscopy requires;
→An energy source (commonly a laser, but this
could be an ion source or radiation source) and
What Instruments Are Needed?
→ A device for measuring the change in the
energy source after it has interacted with the
sample (often a spectrophotometer or
interferometer).
Dedector: