Titrimetric Analysis of drugs based on 1)Neutralization 2)Hydrolysis 3)Oxidation 4)Reduction 5)Non-Aqueous

1. INSTRUMENTATION ASSIGNMENT
GROUP#3:
Group Members:
Komal Yaqoob BPD02181211
Zoha Abbas BPD02181065
Muqaddas Latif BPD02181153
Qurat ul Ain BPD02181229
TOPIC NAME:
“Titrimitric Analysis of Drug Based on:
 Neutralization
 Hydrolysis
 Oxidation
 Reduction
 Non Aqueous Titration”
SUBMITTED TO:
Mam Rushda Beedar
THE UNIVERSITY OF LAHORE
PHARMACY DEPARTMENT
“TITRIMETRIC ANALYSIS”

2. INTRODUCTION:
“Titrimetry is the analytical study in which the volume act as analytical signals. The basic
experimental operation in titrimetric analysis is called a titration.”
 In titration, a solution of accurately known concentration is added to a second reactant,
the solution of sample whose amount or concentration is to be determined
 Titrant is added to asample (titrand) until theamount of titrant is chemically equivalent
to theamount of titrand.
 The stage at which equivalence occur is called the equivalence point andexperimental,
it is calledend point
 .From the amount oftitrant use to reach the end point, its concentrationand known
stoichiometryof the titration reaction. We are able to calculatethe amount or
theconcentration of same substance.
INSTRUMENTATION:
 The only essential instrumentfor an acid - base titration is means fordelivering
thetritrantto the titrand.
 The most common method for delivering the titrant is a burette. A burette is a long
narrow tube with graduated markings and equipped with a stop cork for dispensing the
titrant.
 The burette’s small internal diameter provides a better defined meniscus making it
easier to read the volume preciously.
 A titration can be automated by using a pump to deliver the titrant at a constant flow
rate. Automated titrations offer additional advantage of using a microcomputer for
data storage and analysis.
DETERMINATION OFEND POINTIN TITRATION:
Determinationof end point in titration isas possible on the basis ofdifferent techniques as
described below:

3. 1 ) Finding the end pointwith an indicator:
Oneinteresting group of weak acidsand weak bases are organic dyes.
 Because an organic dyes has at least onehighlycolored conjugateacid and base species,
its tiltration ,results in a change in bothpH and color.We can use this changein color to
indicate theend point of a titrationand provided that itoccurs at or near thetitrations
equivalence point.
Examples of such indicator include:
 Cresol red
 Thymol blue
 Bromophenol blue
 Methyl orange
 Phenolphthalein
 Methyl red etc
2) Finding the end point by monitoring the pH:

4.  An alternative approach for locating titrations end point is to continuously monitor the
titrations progress by using aSensor whosesignal is a function of titrand’s / analyte
concentration.
 The result is a plot of the entire titration curve, which we can use to locate the end point
with the minimal error.
 The obvious sensor for monitoring the acid base titration is the pH electrode and the
result is the potentiometrictitration curve.
 As most of the titration is based on neutralization principle. So end point is achieved as
the pH approaches to 7.
3)Finding the endpoint by monitoringthe temperature:
End point of the titrationcan also be determinedby continuous monitoringof the titrands
temperature. This is called titrationbranch.
 The reaction betweenacid, base is exothermicreaction.Before adding the titrantto the
titrand, changesin the titrand’s temperature are due toenvironmental factors, butas the
titrant is addedto the sample the temperaturebegansto rise.
 The temperature continues to rise with each addition of titrant until we reach the end
point. After the end point, any change in temperature is due to the titrant’s enthalpy of
dilution and the difference between the temperature of titrant and titrand.

5. 4) Finding the end point by monitoring the Amperometry:
 Measures the current produced by the titration reaction as a result of the oxidation or
reduction of the analyte.
 The endpoint is detected as a change in the current.
 This method is most useful when the excess titrant can be reduced, as in the titration of
the halides with Ag+.
5)Isothermal titration calorimeter:
 An instrument that measures the heat produced or consumed by the reaction to
determine the endpoint.

6.  Used in biochemical titrations, such as the determination of how substatres bind to
enzymes.
PRINCIPLES OFTITRIMETRICANALYSIS:
There are different principles on which the titrimetric analysis is based. These include:
1) Neutralization and hydrolysis
2) Oxidation and reduction
3) Non- aqueous titrations
1) Neutralizationand Hydrolysis basedtitrations:
 These titrations are also called as acid base titrations. According to this principle, the
effect of the sample is neutralized by the addition of titrant.
 A sample which may be acid or a base has a specific pH which is more or less than the
neutral pH i.e 7. Upon addition of titrant the pH approaches the neutral pH that is 7 as
the equivalence point is reached.
 Acid base titrations can be further classified as follows depending upon the strength or
pH of titrant and titrand or sample. In these titrations, the titration curve is a graph of
pH against the volume of the titrant added during a titration.
So pH is calculated by Henderson-Hasselbalch equation:

7. pH = pka + log [conjugate base] / [weak acid]
Where pka is the dissociation constant. This type of titration can be occurred between:
1) Strong acid and strong base titration
2) Strong acid and weak base titration
3) Strong base and weak acid titration
HCOOH (aq) + KOH HCOOK (aq) + H2O (l)
Here the reaction is creating the salt, potassium formate. Because a strong base was used and
the salt that was formed is a soluble salt.
Ionic equation is:
HCOOH (aq) + OH- HCOO- (aq) + H2O (l)
When you add enough strong base to react with all of the week acid, all that will remain will be
potassium formate. The HCOO- from the salt will then hydrolyse in solution to determine the
pH at this point
2)Redox Titration:
 A titration that is based on the oxidation reduction reaction between the analyte or
sample and the titrant.

8.  The titrimetric method in this case is mainly based upon the change of the oxidation
number or electrons transfer betweenthe reactants i.e these reactions are mainly
based upon the oxidation reduction reactions. In redox titration, a reducing substance
is titrated with standard solution of an oxidizing agent or vice versa.
Principle:
The principle involved in the oxidation reduction titrations is that the oxidation process
involves the loss of electrons whereas the reduction process involves the gain of electrons.
Theory:
The oxidation leads to the increase in the oxidation number and reduction leads to the
decrease in the oxidation number and if we talk about the electrons then basically oxidation is
the loss of electrons while reduction is gain of electrons. So it means oxidizing agents undergo
reduction and reducing agents undergo oxidation.
Redox indicators:
 Redox indicators should be able to possess the sudden change at the equivalence
point during the redox titration.
 It should be capable of undergoing the oxidation and reduction. The indicators can
be of 2 types:
1) Self indicators:
The titrant itself acts as a self indicator and it shows the intense color at the end point. For
example:

9.  potassium permagnate (KMnO₄) end point is pink to color less.
 Iodine end point is brown to black color.
2) Internal indicator:
These are added to the reaction mixture during the titration. For
example:
 Phenanthroline blue
 Methylene blue etc.
3) Non-aqueous titrations:
 Almost all of the organic substances are insoluble in water and thus cannot be
determined with ordinary titrimetric analysis.
 In 1912, another method for the determination of such substances was introduced. In
this method, the substances are titrated or analyzed during non-aqueous solvent.
Principle:
The organic acid or bases are insoluble in water. These are extremely weak and cannot be
analyzed using normal method. So the non-aqueous titrimetric method is used and the main
principle involved in this method is the samples are dissolved in the non-aqueous solvents.
Example:
Titration analysis of pyridine which is very weak base and used as sample dissolved in acetic
acid which is acidic solvent titrated with perchloric acid (HClO₄) (titrant) dissolved in acetic acid.

10. HClO₄ +CH₃COOH CH₃COOH₂⁺ + ClO₄¯
C6H5N + CH₃COOH C6H5NH⁺ + CH₃COO‾
CH₃COOH₂⁺ + CH₃COO- 2CH₃COOH
Summing up:
HClO₄ + C6H5N C6H5NH⁺ + ClO₄‾
APPLICATIONS OF TITRIMETRIC ANALYSIS:
1) Pharmacist used titration for quality assurance and determination of different
substances.
2) Anesthetics concentrations are determined before administering them to the patients
before major surgeries.

11. 3) Titration is also used to measure the blood glucose level in the diabetic patients.
4) Food industry uses titration to determine the amount of saturated and unsaturated
fatty acids.
5) Titration helps in the determination of salts, sugar and various vitamins in the food that
we consume.
6) Used for the standardization of bio-diesel in the auto mobile industry.