Different methods of analysis
Content
• The different types of Titrimetric analysis
• Apparatus used for titration process
• Different methods of volumetric titration
Learning Objectives
At the end of this
lecture, the student will be able to
• Define and classify the different types of Titrimetric
analysis
• List of apparatus used for titration process
• List the methods for expressing concentrations in
volumetric analysis
• Explain different methods of volumetric titration
Analytical
Chemistry
- Analytical chemistry deals with separating, identifying,
and quantifying the relative amounts of the components of an analyte.
- Analyte = the thing to analyzed; the component(s) of a sample
that are to be determined
The role of analytical chemistry: central science
The relationship between analytical chemistry and the other
sciences
Analytical chemistry
Chemistry:
Biological, Inorganic, Organic, Physical
Physics: Astrophysics, Astronomy, Biophysics
Biology: Botany, Genetics, Microbiology, Molecular biology,
Zoology
Geology: Geophysics, Geochemistry, Paleontology,
Paleobiology
Environmental science: Ecology, Meteorology, Oceanography
Medicine: Clinical, Medicinal, Pharmacy, Toxicology
Material science: Metallurgy, Polymers, Solid state
Engineering: Civil, Chemical, Electronical, and Mechanical
Agriculture: Agronomy, Animal, Crop, Food, Horticulture,
Soil
Social Science: Archeology, Anthropology, Forensics
Pharmaceutical
analysis and its scope
1. Clinical analysis - Blood, urine, feces, cellular fluids,
etc., for use in diagnosis.
2. Pharmaceutical analysis - Establish the physical
properties, toxicity, metabolites, quality control, etc.
3. Environmental analysis - Pollutants, soil and water
analysis, pesticides.
4. Forensic analysis - Analysis related to criminology; DNA
finger printing, finger print detection; blood analysis.
5. Industrial quality control - Required by most companies
to control product quality.
6. Bio analytical chemistry and analysis - Detection and/or
analysis of biological components (i.e., proteins, DNA, RNA, carbohydrates,
metabolites, etc.). This often overlaps many areas. Develop new tools for basic and clinical research.
Classification
of Analytical Chemistry
Qualitative analysis
What is present?
-Determination of chemical identity of the species in the
sample.
Quantitative analysis
How much present?
Determination of the amount of species or analytes, in
numerical terms
Classification
of Quantitative Analysis
Chemical Methods
Electrical Methods
Instrumental methods
Biological and microbiological
1. Chemical
Methods
Volumetric or titrimetric methods
Gasometric analysis
Gravimetric methods
2.
Electrical Methods
Polarography
Potentiometry
Conductometry
Voltametry
Amperometry
3. Instrumental
Methods of Analysis
Spectroscopic methods
Chromatographic techniques
4. Biological and
Microbiological Methods
Antimicrobial assay based on Cup plate method
Bioassay for malaria parasite
Titrimetric
Method of the Analysis: The Basic Concepts and Classification
• Titrimetry - Any method in which volume is the signal
• Titrimetry: In which we measure the volume of a reagent
reacting stoichiometrically with the analyte
• Titrimetric method is also referred as Volumetric analysis
Volumetric
analysis
It is a general term for a method in quantitative chemical
analysis in which the amount of a substance is determined by the measurement of
the volume that the substance occupies
It is commonly used to determine the unknown concentration
of a known reactant
Volumetric analysis is often referred to as titration, a
laboratory technique in which one substance of known concentration and volume
is used to react with another substance of unknown concentration
The Basic Principles
of Volumetric Analysis
• The one solution to be analyzed contains an unknown amount
of chemicals
• The reagent of known concentration reacts with chemical of
unknown amount in the presence of an indicator to show the endpoint
• The volumes are measured by a titration which completes
the reaction between reagent and solution
• The volume and concentration of reagent used in the
titration give the amount of reagent in moles
• The amount of unknown chemical in the measured volume of
solution is calculated by using the mole ratio of the equation
• The amount of unknown chemical in the original sample is
calculated by the amount of unknown chemical in the measured volume
Definition
of Terms: Used in Analysis
Titration: It is a
procedure for determining the concentration of a solution by allowing a
carefully measured volume to react with a standard solution of another substance,
whose concentration is known
•A + T → products A: analyte T:
titrant
Titrant: A
reagent of exactly known concentration that is used in titrimetric analysis
Titrate: A test
solution is one whose concentration is to be estimated
Indicator: Some
substances added to which are basically organic dyes, used to detect the end
point
End point
– The point at which the reaction is observed to be
completed is the end point
– The end point in volumetric method of analysis is the
signal that tells the analyst to stop adding reagent and make the final reading
on the burette
– Endpoint is observed with the help of indicator
Equivalent point
– The point at which an equivalent or stoichiometric amount
of titrant is added to the analyte based on the stoichiometric equation
Requirements
in Titration
• Stoichiometric reaction
• Rapid rate reaction
• Quantitative reaction (99.9%complete at stoichiometry)
• Have a defined end or equivalence point
• Reaction should have no side reaction, no interference
from other foreign substances
• Must have some indication of end of reaction, such as
color change, sudden increase in pH, zero conductivity, etc
• Known relationship between endpoint and equivalence point
The
Different Glass Ware Used in Volumetric Analysis
• Volumetric analysis involves a few piece of equipment:
Pipette – for measuring
accurate and precise volumes of solutions
Burette – for
pouring measured volumes solutions
Conical flask – for mixing two solutions
Wash bottles –
these contain distille water for cleaning equipment
Funnel – for
transfer of liquids without spilling
Volumetric flasks –
a flask used to make accurate volumes for solutions of kn concentration
Experimental
Set-up in the Laboratory
• Two solutions are used: They are prepared according to the
strength as per the requirements
– The solution of unknown concentration
– The solution of known concentration – this is also known as
the standard solution
• Write a balanced equation for the reaction between your two
chemicals
• Clean all glassware to be used with distilled water. The
pipettes and burettes will be rinsed with the solutions which are been used for
the experiment
Process – The Setup
• The burette is attached to a clamp stand above a conical
flask
• The burette is filled with standard solution (in this case
a yellow standard solution)
• A pipette is used to measure an aliquot of the other
solution whose concentration has to be determined (in this case a purple
solution unknown concentration) into conical flask
• Prepare a number of flasks repeat tests
• Last, an indicator is added to conical flask
Process – The
Titration
• Read the initial level of liquid in the burett and make a
note of it in the lab manual
• Turn the stop cock
to add the standard solution from the burette into the conical flask
Swirl the flask continuously
• So that every drop of analyte reacts with titran in
presence of an indicator
• When the colour changes permanently, stop the addition of
titrant read the final volume the volume change needs to be calculate (and
written down). This volume is called
titre
• Repeat the titration with a new flask until consecutive
concordant readings are obtained
Summary:
Analytical Chemistry:
• Qualitative analysis: Determination of chemical identity
of the species in the sample.
• Quantitative analysis: Determination of the amount of
species or analytes, in numerical terms
• Classification: Chemical,, instrumental, Electrical
Methods and Biological and microbiological
• Terms used in analysis: Titrate, titrant, end point and
• The various apparatus used for titrimetric are: Burette, pipette,
conical flask, beaker, standard flask, weights, analytical balance
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