Different methods of analysis - Pharmaceutical Analysis 1 B. Pharma 1st semester

Different methods of analysis


• 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






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


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


Post a Comment