Download introduction into Analytical Chemistry

Pharmaceutical Analytical
Chemistry / PHC 213
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Analytical Chemistry
is the study of the separation, identification, and
quantification of the chemical components of
natural and artificial materials
Analytical chemistry answer two
important questions
How much is it ??
What is it ??
(quantitative analysis)
(Qualitative analysis)
determines the amount
gives an indication of the
(concentration) of one or
identity of the
more of the components
chemical species in the
in the sample
sample
Classification of Analytical Methods :
Gravimetric method
Volumetric method
Instrumental methods
Gravimetric method :
Gravimetric methods of analysis are based on
the measurement of mass.
Volumetric method (Titration(:
involves the addition of a reactant to a solution
being analyzed until some equivalence point
is reached
Types of Titration:
Acid _ base titration
Precipitimetric titration
Complexmetric titration
Redox(oxidation-reduction) titration
Instrumental methods :
 Spectrophotometry
Chromatography
Application of Analytical Chemistry :
Analytical chemistry play an important role in
nearly all aspect of chemistry
 Medicine
 Industry
 Environmental
 Food and Agriculture
 Quality control
Application of Analytical Chemistry :
In medicine, analytical chemistry is the basis
for clinical laboratory tests which help the
physicians diagnose disease
In industry, analytical chemistry provides the
means of testing the raw materials for
assuring the quality of finished products
whose chemical composition is critical (eg.
Drugs )
The nutritional value of food
determined by chemical analysis for
major component such as protein and
carbohydrate and trace components
such as vitamins and minirals
Definition of some terms :
Sample:
is a material that we wish to analyze
 Analyte:
is the substance or element in the sample whose
presence or concentration we wish to determine
 titrant:
is a solution of known concentration which is added
(titrated) to another solution to determine the
concentration of second chemical species
Titration:
is a process which is performed
by
slow addition of standard
solution
"titrant" from a burette to
a solution of the analyte until
the reaction between the two
is complete.
Standard Solution:
- is a solution of known concentration
- prepared by dissolving a known amount of the
substance (primary standard substance)in a known
volume of liquid
- They provide a reference to determine unknown
concentrations
-Two types,, primary and secondary standard solution
Standard solution
Secondary standard
Primary standard
1-Must be easily obtained in very high
grade of purity and of known
composition.
2-Very stable, and resists reactions with
air
( non-hygroscopic )
3- It is recommended to have high
equivalent weight to minimize
weighing error.
1-The concentration of which
can’t be directly calculated from
the weight of the solute and
volume of the solution.
2- The exact concentration is
determined by:
- Titration against a primary
standard solution
4- It must react with other substances in
quantitative way according to
balanced chemical equations
(stoichiometry)
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Dr. Hadir Shalaby
Examples:
Standard solution
Primary standard
Acids
Secondary standard
potassium acid phthalate, oxalic
acid, benzoic acid, sulphamic acid.
Hydrochloric acid, sulphuric acid.
Borax, sodium carbonate.
Sodium hydroxide, ammonia
Oxidizin
g agents Potassium dichromate, potassium
bromate and potassium iodate.
Potassium permanganate
Bases
Reducing agents
Sodium oxalate, arsenious
oxide, and potassium ferrocyanide.
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Dr. Hadir Shalaby
Equivalence point:
The point in a titration
when the amount of added
standard reagent is exactly
equal to
( is chemically equivalent
to) the amount of the
analyte.
End point:
The point in a titration
when a physical change
occurs that is associated
with the condition of
chemical equivalence.
Volume difference between the equivalence point
and the end point should be small .
This difference in volume is the titration error
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Detection of the end point
Indicator :
a substance that indicate the presence, absence, or
concentration of another substance ,,often used in a
titration to indicate the point at which the reaction is
complete by means of a characteristic change,
especially in color
such as: litmus paper
in acid media
in base media
Methods of expressing concentration of standard
solutions
I-Molarity
Molar solution:
It is a solution of the substance containing one mole (gram
molecular weight) of the substance per one liter of solution.
Molarity (M) :
It is the number of moles (gram molecular weight )of solute
per one liter of solution.
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Dr. Hadir Shalaby
Some useful algebraic relationships:
M = no. moles solute
V( L)
M=Molarity
V=volume in liter
No. of moles = M x V ( L )
No. of moles = wt.solute, g
fwt
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Dr. Hadir Shalaby
Fwt= formula
weight or
molecular
weight ( g)
Examples:
Example 1:
Calculate the molarity of 17g Na2CO3 in 500ml of solution
(fwt=106)
Convert 500 ml
to liter by
M= …… wtg …….. =
17
= 0.320
÷1000 = 0.5 L
fwt × VL
106 × 0.5
Example 2: ( HOME WORK)
Calculate the weight in grams of Na2CO3 required to
prepare 250ml of 0.15M solution. (fwt=106)
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Dr. Hadir Shalaby
II-Normality
II. Normal solution:
It is the solution that contains one gram equivalent weight
of solute per liter of solution.
Normality (N) :
It is the number of equivalents (gram equivalent weight) per
liter of solution.
If the equivalent weight = formula weight
so,
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N=M
Dr. Hadir Shalaby
Normality (N) = Number of equivelant weight
Volume(V) in (Liter)
No.of eq.wt = N x V(L)
OR \
No.of eq.wt = weight of solute (g)
equivalent weight (Eq.wt)
Eq.wt = Formula weight (F.wt )
n (no. of (H+) OR (OH-) )
N=nM
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Dr. Hadir Shalaby
N=Normality
n = number of
(H+) or (OH-)
M= Molarity
Problem???
Calculate the eq.wt for each of the following:
HCl , H2SO4 , H2CO3 , H3PO4 , Ba(OH)2
*In case of HCl or NaOH
HCl  1 H+ eqwt = fwt / 1
NaOH  1 OH*In case of Ba(OH)2
Ba(OH)2  2 OHeqwt = fwt / 2
*In case of H3PO4
H3PO4 
H2PO4- + H+
eqwt = fwt / 1
H3PO4 
HPO4-2 + 2 H+
eqwt = fwt / 2
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Dr. Hadir Shalaby
Examples:
1-How much primary standard potassium acid phthalate,
KHC8H4O4, is required to prepare 499.5 ml of 0.10 N
solution?(fwt = 204.23)
Weight ( g) = ??
Convert 499.5 ml to Liter
by ÷1000 = 0.4995 L
No of eq.wt = N x V (L)
Wt/ eqwt = N x V
Wt ( g) = N x V x eqwt
= 0.1 x 0.4995 x 204.23
= 10. 20 g KHC8H4O4
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Dr. Hadir Shalaby
TYPES OF WATER USED:
• Distilled water:
is water that has many
of its impurities
removed through
distillation
• Deionized water :
is water that has had
all minerals removed
from it,as cations like
sodium, calcium,
iron, and copper, and
anions such as
chloride and sulfate,
using an ion
exchange process
Lab glassware and equipment
burette
Pipette:
Graduated pipettes
Volumetric pipettes
beaker
cylinder
funnels
Volumetric flask
Conical flask:
Glass stopper conical flask
Conical flask
Glass rod
Mortar and pestle
Hot plate
electronic balance
hood
 GENERAL GUIDELINES:
1- When first entering the lab , do not touch any
equipment, chemicals, or other materials in the
laboratory area until you are instructed to do so
2- Follow all written and verbal instructions carefully. If
you do not understand a direction or part of a
procedure, ASK YOUR TEACHER BEFORE
PROCEEDING WITH THE ACTIVITY
3- Never work alone in the laboratory,No student may
work in the laboratory without the presence of the
teacher
4- Do not eat food, drink beverages, or chew
gum in the laboratory,Do not use
laboratory glassware as containers for
food or beverages
5- Observe good housekeeping
practices , Work areas should be
kept clean at all times
7- Labels and equipment instructions
must be read carefully before use
8- Keep hands away from face, eyes, mouth,
and body while using chemicals , Wash your
hands with soap and water after performing
all experiments
9-you should Know the locations and
operating procedures of all safety
equipment
 CLOTHING:
Dress properly during a laboratory activity.
Long hair must be tied back, Shoes must
completely cover the foot
 HANDLING CHEMICALS:
1- All chemicals in the laboratory are to be considered
dangerous. Avoid handling chemicals with fingers , Do
not taste or smell any chemicals
2- Check the label on all chemical bottles twice before
removing any of the contents
3- Never return unused chemicals to their original
container, and Never remove chemicals or other
materials from the laboratory area
 HANDLING GLASSWARE AND
EQUIPMENT:
1- Never handle broken glass with your hands ,
Place broken glass in the sharps container
2- Examine glassware before each use
3- Never look into a container that is being heated
4- hood (how can we use it in the safe way )
COURSE SYLLABUS:
Thank you