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1. By Imtiyaz Bagban
M. Pharm. (Pharmacology)
Assistant Professor
Department of Pharmacology
Krishna School of Pharmacy & Research (KSP)
Drs. Kiran & Pallavi Patel Global University
(KPGU)
1
Introduction to
Pharmaceutical Analysis
B. Pharm. Semester I
Subject – Pharmaceutical Analysis
Subject Code- BP102T
UNIT 1

2.  Contents
• Definition and Scope Pharmaceutical Analysis.
• Different techniques of analysis.
• Methods of expressing concentration.
• Primary and secondary standards.
• Preparation and standardisation of various molar and normal solution:
Oxalic acid, sodium hydroxide, hydrochloric acid, sodium
thiosulphate, sulphuric acid, potassium permanganate and ceric
ammonium sulphate
• Errors : Sources of errors, types of errors, methods of minimizing
errors.
2

3.  Pharmaceutical analysis
• Pharmaceutical analysis is a branch of practical chemistry that involves a
series of process for identification, determination, quantification and
purification of a substance, separation of the components of a solution or
mixture, or determination of structure of chemical compounds
3

4. 1. In pharmaceutical industry- There are different sectors in pharmaceutical industry as
research and development (R&D) and Quality control (QC) in which pharmaceutical analysis
utilizes regularly.
2. In Food industry- As we all know packed food which consumed by consumer should have
all parameters like quality, purity and safety which enhance acceptability by consumer. For
this it is require analyzing all these parameters for packed food.
Different kind of preservatives, coloring, flavouring and sweetening agents are used in packed
food which can natural or synthetic chemical ingredient so these should analyze qualitatively
and quantitatively, for this various kind of analytical techniques can be applicable.
3. In Cosmetic Industry- Preparation of cosmetics, as lipsticks, creams nail paints, lotion
shampoo and conditioners etc play with two things as colour and odour and these colouring
agents and fragrances are also build by different chemical ingredients so the quality and
quantity of these ingredients should be known which can be analyse by different techniques of
analysis.
4. In Disease diagnosis- Different disease can be diagnosed by pharmaceutical analysis
techniques like HIV is observed by ELISA method 4
 Scopes of analysis

5. 5.Geology- Geologist uses analytical procedure for analyzing ground water, minerals,
soil sample etc.
6. Environmental science- Many industrial process give raise to pollutants which can
present health problem. Quantitative analysis of air, water and some times soil sample
carried out to determine the level of pollution and establish safe limits for pollutants.
7. Agriculture science- In farming the nature and level of fertilizer application is based
on information obtained by anlayzing soil to determine its content of essential plant
nutrients, nitrogen, phosphorus, potassium and trace elements required for healthy plant
growth.
8. Government legislation can only be enforced by the work of analytical chemist, e.g
national and international agreements on water pollution and atmospheric pollution,
regulation on substances hazardous to health and laws governing the misuse of drugs.
5

6.  There are main two types of chemical analysis
• Qualitative analysis- These tests are performed to indicate whether
the substance or compound is present in the sample or not.
• Various qualitative tests are detection of evolved gas, formation of
precipitates, limit tests, color change reaction, melting point and
boiling point test etc.
• Quantitative analysis- Techniques are mainly used to quantify any
compound or substance in the sample. 6
1. Qualitative analysis ( identification )
2. Quantitative analysis ( estimation )

7.  Quantitative analysis are classified as
1. Chemical Methods
A. Volumetric Method- In volumetric methods assay is
based on the measurement of volume of solution of
known strength that is required to react completely
with the substance to be analyse
• Neutralization- Neutralisation reaction between acid
and base
• Precipitation titration- The reaction between titrate and
titrant result in formation of precipitates.
• Complexometric titration- it include complex
formation between the analyte and titrant.
• Redox titration- The titration based on redox reaction
7

8. B. Gravimetric Methods- Gravimetric analysis is a quantitative
analysis by weight and is a process of isolating and weighing
the compound of known composition. i.e. purest form
• The separation of compound is affected by number of ways
like precipitation, volatilization etc
C. Gasometric Methods- These methods involve measurement
of the volume of gases
• These measure gas liberated in the given chemical reaction
under the conditions that are described in the process.
• The volume measured is corrected to standard conditions of
temperature and pressure.
• Decrease in the volume of gas when a suitable agent is placed
to absorb one of the gases present and reduced to standard
conditions of temperature and pressure.
• Cyclopropane, CO2, Nitrous oxide, O2, octyle nitrate, amyl
nitare and nitrogen gases are determined by these method
• Gas Burettes and Nitrometer

9. 2. Instrumental Methods
A) Electrical Methods
• Voltametry- measurement of current at a microelectrode
• Coulometry-measurement of current and time to complete
electrochemical reaction
• Potentiometry- measurement of potential of an electrode
• Condutometry- measurement of electrical conductivity
• Electrogravimetry- electrolysis is carried out and material deposit on electrode is weighed
B) Spectroscopic Methods
a) Absorption Methods-
Visible spectroscopy, Infrared spectroscopy,
UV spectroscopy,
Nuclear Magnetic Resonance Spectroscopy,
Mass spectrometry
b) Emission Methods- Flame photometry, Fluorimetry
9

10. c) Thermal Methods
I. Thermogravimetry
II. Differential thermal analysis
III. Differential scanning calorimetry
d) Separation Methods
a) Chromatographic Methods-
HPLC, TLC, HPTLC,
Paper chromatography,
Gel chromatography,
Ion exchange chromatography
II. Electrophoretic Methods
10

11. 3) Microbiological Method-
• The microbiological assay is based upon comparison of the inhibition of growth of
bacteria by measured conc. of antibiotics to be examined with that produced by known
conc. of standard preparation of antibiotics having known activity.
I. Cylinder plate method ( cup plate)
II. Turbidimetric method
4) Biological Method-
• Biological analysis are carried out to observe biological effect of drug on some living
matter they also called bioassay.
• This method carried out by comparing biological effect of sample to be tested with
biological effect produced by standard compound in identical test condition.
• Bioassay involves measurements of various parameters including tissue of organ,
weight of organ, blood parameters such as blood glucose, cholesterol urea, enzyme
conc.etc
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12.  Methods of expressing concentration
• Concentration is a general term that expresses the quantity of solute contained in a given
amount of solution.
• Solute - Substances that are dissolved
• Solvents- Substance in which solutes are dissolved (usually water)
• Titrant- A solution of known concentration
• Analyte- A solution of substance which is titrated
• Indicator- it is an auxiliary reagent used in all stoichiometric reactions to detect end point
of the reaction.
• Equivalence point- a point at which the reaction just completed.
• End Point-when the reaction between titrant and analyte just complete and the indicator
gives a visual color change in the liquid.
• Stoichiometric end point- equivalent quantity of titrant and analyte has reacted is called
Stoichiometric end point 12

13. Concentration can be express in
1. Molarity (M)
2. Molality (m)
3. Normality (N)
4. Formality (F)
5. Parts per million (ppm)
6. Mole fraction
7. By Percentage

14. • Molar Concentration /Molarity (M) – It is the number of moles of solute dissolved in
1 lit of solution
Molarity (M) = Number of moles of solute
Volume of solution in L
• Volume temperature dependent – Molarity can change with temperature
• Example - 1 mole (40g) of NaOH dissolved in 1 litere solution said to be 1M
• Half mole (20g) of NaOH dissolved in 1 litter solution said to be 0.5M
• Half mole (20g) of NaOH dissolved in 500ml solution said to be 1M
Molal concentration /Molality (m) – Although rarely practice It is defined as number of
moles of solute dissolved in 1000g of solvent
Molality (m) = weight of solute × 100
Weight of solvent × Mol. wt. of solvent 14

15. • Equivalent Weight – The equivalent weight of a substance is defined as the
parts by weight of that substance which is chemically equivalent to 1.008 parts
by weight of hydrogen.
• Equivalent Weight = Molecular Weight
Acidity/Basicity
• EX 1) HCL Eq. Wt = 36.5/1=36.5
• 2) H2SO4 Eq.Wt = 98/2=49
15
Equivalent
Acid
Base
Salt

16. Equivalent Mass of Acid (Neutralization Reaction)
• Equivalent mass of acid =
Molecular mass acid
Number of replaceable OH-(Basicity)
Example
Equivalent mass of HCL and H2SO4
HCl 
H
 CL
H2SO4
 2H
 SO4
--
Equivalent mass of HCl = 1+35.5 = 36.5
1
Equivalent mass of H2SO4 = 32 + 4 × 16 + 2 × 1 = 49
2
16

17. Equivalent Mass of Base (Neutralization Reaction)
• Equivalent mass of base =
Molecular mass
Number of replaceable OH-(Acidity)
Example
Equivalent mass of NaOH and Ca(OH)2
NaOH 
Na
 OH
Ca(OH)2 
Ca
 2OH
Equivalent mass of NaOH = 23+16+1 = 40
1
Equivalent mass of Ca(OH)2 = 40+2 × 16 + 2 × 1 = 37
2 17

18. Equivalent Mass of Salt ( Complexometric and Precipitation Reaction)
• Equivalent mass of salt =
Molecular mass
Total number of positive or negative charge
Example
Equivalent mass of NaCl and MgCl2
AgNO3  Cl

 AgCl ↓  NO3

NaCl  Ag

 NA
 AgCl
Equivalent mass of AgNO3 = 169.9/1 = 169.9 g/mol
Equivalent mass of NaCl = 58.44/1 = 58.44 g / mol
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19. Equivalent weight in Oxidation and Reduction Reaction
a) Ion Electron Method
• Ascertain the reactants and products of the reaction.
• Write partial equation for oxidising and reducing agent.
• Example:
• Reduction:- Mno4
- → Mn  
• The balance atomically and electrically
Mno4
- + 8H+ + 5e → Mn  
 2H2O
• Equivalent weight =
Molecular weight
Number of electron transferred
Equivalent weight of KMnO4 = 158/5 = 31.6
19

20. • Oxidation:
• Example
Fe+2 → Fe+3
The balance electrically
Fe+2 -e → Fe+3
• Equivalent weight =
Molecular weight
Number of electron transferred
Equivalent weight of FeSO4 = 278/1 = 278
b) Oxidation Reduction Method
• Oxidation and reduction method are the process involving the changes in the valency.
• Oxidation Number (O.N) indicates the amount of oxidation or reduction required to
convert on atom of the element from free state to that in the compound.
• If oxidation takes place O.N is positive and If reduction takes place O.N is negative.
20

21. • O.N of free or uncombined element is zero.
• O.N of hydrogen ( except hydrides ) is +1
• O.N of Oxygen (except peroxides) is -2
• Equivalent weight =
Molecular weight
change in O.N
Example:
(I) K+Mn+7O4
-8 → Mn+2S+6O4
−8
change in oxidation number of manganese is from +7 to +2
Equivalent weight = 158/5= 31.6
(II) 2Fe+2S-2O4 → Fe2
+6(SO4
-6)3
Change in O.N of iron is from +2 to +3 hence
Equivalent weight = 151.90/1= 159.90
(III) K2
+2Cr2
+12O7
-14 → Cr2
+6(SO4
-6)2
Change in O.N of iron is from +12 to +6 hence
Equivalent weight = 294/6 = 49
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22. Normality (N) - it is the number of equivalent weight of solute dissolved in 1
litter of solution
Normality (N) = Weight of solute
Equivalent Weight × Volume of solution in liter
• Normality varies according to the reaction as the equivalent weight of a
substance may very according to the reaction in which the solute precipitates.
Formality / Formal solution
• Some substances do not exist in molecular form whether in solid or solution
form they remain in ionic form in solid state as well as in solution
• In such cases instead of mol. wt. formula weight used in preparation and its
conc. expressed in terms of formality
Formality (F) = Weight of solute Formula weight
• Volume of solvent
 Parts per Million – Parts per Million is frequently used to express the conc.
Of vary solution and is expressed as “ppm”
22

23.  Mole fraction (X)- it is defined as moles of component divided by total
number of moles making up solution
Mole fraction (x) = Moles of of component
total number of moles making up solution
• Example- A solution is prepared by dissolving 1 mole of ethyl alcohol
C2H5OH in 3 moles of water where nA and nB represent the number of moles
of ethyl alcohol and water respectively
• Mole fraction of ethyl alcohol = XA= nA/nA+nB
=1/1+3=1/4=0.2
• Mole fraction of water =XB= nB/nA+nB=3/1+3=3/4=0.75
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24. 24
By Percentage
 Volume Percentage (v/v)
• It is defined as the volume of solute in mL present in 100 mL solution.
Volume % = (volume of solute/ total volume of solution) X 100
• For example:
• 10% solution of HCl by volume means that 10 mL of liquid HCl is present in 100 mLof the solution.
 Mass by Volume Percentage (w/v)
• It is defined as the mass of solute present in 100 mL of solution.
Mass by Volume % = (mass of solute/ total volume of solution) X 100
• For example:
• A10% mass by volume solution means that 10 gm solute is present in 100 mL of solution.
 Mass by Mass Percentage (w/w)
• It is defined as the mass of solute present in 100 gm of solution.
Mass % = (mass of solute / total mass of solution) X 100
• For example:
• A10% mass by volume solution means that 10 gm solute is present in 100 gm of solution.

25. 1.Calculate the masspercentageofaspirin(C9H8O4)inacetonitrile(CH3CN) when 6.5 gofC9H8O4 is
dissolvedin450 gof CH3CN.
Ans.Mass of solution = 6.5g + 450g = 456.5g
Mass% of aspirin= Mass of aspirin X 100
Mass of solution
= 6.5/456.5 X 100 = 1.424%
2. Calculatethe molarityofa solutioncontaining5 gofNaOHin450 mL.
Ans. Moles of NaOH =5 g/40 g /mol (molar mass of NaOH=40 g /mol)
= 0.125 mol
Volume of the solution in liters = 450 mL / 1000mL/L
=0.45L
Molarity(M)= Moles of NaOH / Volume of the solution in liters
= 0.125 mol / 0.45L
= 0.278 mol /L
NUMERICALS ON CONCENTRATION

26. 3. Calculate the mole fraction of ethylene glycol (C2H6O2) in a solution containing 20%
of C2H6O2 by mass.
Ans. Solution will contain 20 g of ethylene glycol and 80 g of water.
Molar mass of C2H6O2 = 12 × 2 + 1 × 6 + 16 × 2 = 62 g /mol
Moles of C2H6O2 = 20 g/62 g mol = 0.322 mol
Moles of water = 80 g/18 g mol = 4.444 mol
Mole fraction of C2H6O2 = (moles of C2H6O2 /moles of C2H6O2+moles of water)
= 0.322/0.322+4.444 = 0.068
Mole fraction of water = 1-0.068 (mole fraction of C2H6O2 + mole fraction of water=1) = 0.932
4. Calculatemolalityof2.5 gofethanoicacid(CH3COOH)in 75 gof benzene.
Ans. Molar mass of CH3COOH : 12 × 2 + 1 × 4 + 16 × 2 = 60 g /mol
Moles of CH3COOH = 2.5 g/60 g /mol = 0.0417 mol
Mass of benzene(solvent) in kg =75 g/1000 g/ kg =0.075kg
Molality(m)of CH3COOH = Moles of CH3COOH
Mass of benzene(solvent) in kg
= 0.0417 mol/0.075kg
= 0.556 mol/kg

27. 5. Calculate the mass percentage of Benzene (C6H6) and Carbon Tetrachloride (CCl4) if
22g of Benzene is dissolved in 122g of Carbon Tetrachloride.
Ans.
Mass percentage of benzene = Mass of benzene X 100
Mass of solution
=22g X100 /144g = 15.28%
Mass percentage of carbon tetrachloride=100-15.28 = 84.72
6. Calculate the mole fraction of Benzene in solution containing 30% by mass in Carbon
tetrachloride.
Mole fraction of benzene= No. of moles of benzene
(No. of moles of benzene + No. of moles of carbon tetrachloride)
No. of moles of benzene= mass of benzene/molar mass of benzene
= 30g/78g/mol(molar mass of benzene 78g/mol)
=0.385
No. of moles of carbon tetrachloride= mass of carbon tetrachloride/molar mass of carbon tetrachloride
=70g/154g/mol =0.455
Mole fraction of benzene=0.385/(0.385+0.455) = 0.458
Mole fraction of carbon tetrachloride=1-0.458 = 0.542

28. 7. CALCULATE THE MOLARITY OF EACH OF THE FOLLOWING SOLUTIONS:
(A) 30 g OF CO(NO3)2. 6H2O IN 4.3 L OF SOLUTION (B) 30 ML OF 0.5 M H2SO4
DILUTED TO 500 ML.
Ans.
(A)Molarity of solution = No. of moles of solute
Volume of solution in L
No. of moles of solute = Mass of Co(NO3)2. 6H2O
Molar mass of Co(NO3)2.6H2O
=30g/310.7g/mol = 0.0966
Volume of solution in L=4.3L
Molarity of solution=0.0966/4.3=0.022M
(B) M1V1=M2V2
M1=0.5M,V1=30ML, V2=500ML, M2=?
M2=0.5X30/500
=15/500
=0.03M

29. 8. Calculate (A) Molality (B) Molarity and (C) Mole fraction of KI if the density 20%
(mass/mass) aqueous KI is 1.202 g/mL.
Ans. Here Mass of KI=20g,
Mass of solution=100g,
Mass of solvent=80g
(A)Molality(m)=0.12/0.080=1.5m
(B) Molarity(M)=0.12/0.0832=1.44M
(volume of solution=mass of solution/density)
=100/1.202=83.2ml=0.0832L)
(c) Mole fraction of KI= No.of moles of KI
Total no. of moles in solution
= 0.12/(0.12+4.44)
=0.0263

30. 30
Primary Standard
These are extremely pure, stable, it not a hydrate/has no water of hydration, and has a high molecular weight.
Ex. Potassium hydrogen phthalate, Benzoic Acid, Arsenious Oxide, Sodium Carbonate, Sodium Oxalate, Potassium
Iodide, Potassium dichromate, Potassium hydrogen iodate
Properties:
It is extremely pure,
Highly stable
It is anhydrous
It is less hygroscopic
Has very high molecular weight
Can be weighed easily
Should be ready to use and available
Should be preferably non toxic
Should not be expensive

31. Secondary Standard:
 Don’t meet requirements for a primary standard but are available with sufficient
purity and properties to be generally acceptable. It is usually standardized against a
primary standard.
• EX. - NaOH , KOH , Ba(OH)2, HCl , HNO3 , HClO4 Sulfamic Acid, KMnO4 , Na2S2O3
• Properties:
Prepared from primary standard
Stable
Reacts rapidly and completely with analyte
31

32. Quality Control
• Quality control is powerful productivity technique for effective diagnosis of lack of
quality or conformity to settle standards in any of the material.
• The science of quality control is largely statistical in nature. The statistical quality
control technique is based on theory of probability and sampling and is extensively used
in pharmaceutical industries and quality control laboratory.
• Statistical quality control is classified into two part:
• Process control- To maintain satisfactory quality level in production.it ensure that the
product confirms to the specified quality standards.it is achieved through technique of
control chart.
• Product Control- Controlling the quality of product by critical examination at strategic
points which achieved through sampling inspection plans.
• Random samples of work in process are taken and inspected. data collected and
presented in chart from which is essential part of quality control system.
32

33. • Improve quality and uniformity level.
• Better use of raw material.
• Efficient utilisation of equipment.
• Batter inspection.
• Batter specification.
• Improve consumer and manufacturer relation.
33
Objective of statistical quality control

34. QC functions and responsibilities
• This department is staffed with scientist and technicians responsible
for sampling of raw material and inspection of packaging components
, including labelling.
• They conduct in process testing, environment monitoring and inspect
operation for compliances. test on finished dosage form
• QC is responsible for monitoring product quality through
distribution, including testing of product complaint sample,
evaluating product stability etc.
• QC play important in the selection and qualification of vendors from
whom these materials are purchased.
• QC is responsible, as part of its testing and inspection for monitoring
the environmental conditions under which products are
manufactured and held. different level of control are established
depending on intended use of dosage form. Ex Parenteral Product
(sterile condition).
34

35. • Another major element of quality is Non sterile Products such as
liquids, tablets, and capsules. The objective here is to determine an
acceptable level of particulates and microbial contaminates and then to
control them to this level.
• If particulates are found to be excessive steps must be taken to bring
them within acceptable limits. So as not to compromise the quality of
product.
• Control of Packing components especially those that come into direct
contact with a product. These materials must be inspected and tested
against rigid specifications to ensure they meet functional standard.
• Labelling is understandably a critical component not just in original
design and acceptance but also with regard to secure storage and to
ensure accountability. Final product labelling must be inspected to
ensure that it is correct.
35

36. Quality Assurances
• Quality assurance system involves a set of procedure put in place to
ensure that quality control activities are performed.
• QA system permit certain level of confidence to be assigned to result
that are obtained from an analytical procedure.
• QA system normally involves accreditation with an outside
independent organisation within many countries numerous analytical
procedures may now be accredited via for example the International
standards organization.
36

37. Importance of QA
• The Pharmaceutical industry as avital segment of the health care
system.
• Conduct research
• Manufacture and market pharmaceutical and biological products and
medical devices use for acute and chronic treatment and diagnosis of
disease.
• Recent advances in drug discovery are presenting new challenges to
QC and the system that operate internally in the industry.
• The external regulations established by the food and drug
Administration and other regulatory bodies also added to these
challenges.
• Quality must be built into a drug product during product and process
design and it is influenced by physical plant design, space, ventilation,
and sanitation during routine production.
37

38. QA Function and Responsibilities
• QA has to play a major role in the identification and preparation of the
necessary policies and standard operating procedures. (SOPs)
relative to control quality.
• Specification and test for active ingredients, the excipients, and the
product itself,
• Specific stability procedures for the product,
• Freedom from microbial contamination,
• Proper storage of the product and containers, packaging, and
labelling to ensure that container closure systems provide functional
protection of the product against factor like moisture, oxygen, light,
volatility, and drug /package interaction.
• Quality Monitoring – this activity is able to determine if operation
have adequate system facilities and written procedure to control the
quality of product produced.
38

39. • Establish control or checkpoints to monitor the quality of the product
as it is proceed and upon completion of manufacture.
• Raw material and component testing
• In process , packaging, labelling, and finished product testing
• Batch auditing and stability monitoring
• Responsibility for final product release- It must determine that the
product meets all the applicable specification and it was manufactured
according to internal standard an cGMPs.
• Audit Function: QA department combine this reviews of SOPs with
an audit of facilities and operations.
• Then it give company management an inside report on its level of
compliances and will allow the necessary changes or correction to be
made prior to either causing product failure or as a deficiency during
inspection by FDA
39

40. Preparation and standardization of various Molar and Normal solution
• For the preparation of standard solution a known quantity of standard
substances depending upon the requirement is dissolved in known amount of
water and desired volume is made.
• These substances have a constant weight, high purity, non hygroscopic, the
solution is of known and definite concentration.
• Example- Prepare 0.1N Oxalic acid
1) Oxalic acid – (COOH)2.H2O
• Mol.weight – 126
• Acidity – 2
• Equivalent weight – 63
• Therefor weight 6.3gm of oxalic acid (COOH)2.H2O and transfer it in to
volumetric flask and make up to the mark.
40

41. 2) Sodium Hydroxide
Preparation of 0.1N NaOH solution=40
Mol. weight of NaOH= 40
Acidity ( number acceptable Oh groups) = 1
Equivalent Weight of NaOH= 40
Therefor 4g of NaOH dissolved in 1 lit of solution will give 0.1N solution
Procedure
weigh accurately 4 g of NaOH in a beaker and dissolve it in distilled water.
weighing should be performed quickly as it is hygroscopic. Transfer the contents
and the washings to a 1 lit volumetric flask. Cool and then make volume up to the
mark. Shake well.
Standardization
The 0.1N NaOH prepared as per above mentioned procedure is standardized by
titrating against 0.1N Oxalic Acid using Phenolphthalein as an indicator. 10 ml
0.1 N oxalic acid is taken in a conical flask to which 2 – 3 drops of
Phenolphthalein is added and mixed well. 41

42. • This solution is titrated slowly with constant stirring against 0.1N NaOH
taken in burette. Titration is continued till the appearance of permanent pale
pink colour as the end point.
• Calculation of normality of NaOH using formula
• N1V1=N2V2 where N1= Normality of NaOH ?
V1= Volume of NaOH Solution used
N2= Normality of standard oxalic acid solution
V2= Volume of standard oxalic acid solution
3) Potassium Permanganate:
Preparation of 0.1N KMnO4 Solution
Mol.weight of KMnO4 = 158g/mol
Equivalent weight of KMnO4= 31.6
42

43. • Equivalent weight of KMnO4 is reaction specific. In acidic medium
KMnO4 is used as an oxidiser. So there will be 5 electron gained by Mn
atom. Hence the Equivalent weight of KMnO4 = Molecular weight /
Number of electrons gained in redox reaction = 158/5= 31.6 so 3.16 or
3.2 g of KMnO4 is weighed and dissolved in 1 lit of distilled water to get
0.1N KMnO4 solution.
• In alkaline or neutral medium, reaction of KMnO4 is different and Mn
gains 3 electrones in redox reaction. So for alkaline medium redox
titration, Equivalent weight of KMnO4=158/3 =52.6 So 5.26 g of KMnO4
is weighed and dissolved in 1 lit of distilled water to get 0.1N KMnO4
solution.
• Procedure
• 3.2 g of KMnO4 is weighed and dissolved in 1 lit of distilled water to get
0.1N KMnO4 solution. the solution is boiled for 10-15 minutes and then
allowed to stand for few days and filtered through glass wool.
43

44. • Standaradization
• 10ml of 0.1N oxalic acid taken in conical flask. Add 5ml dilute sulphuric
acid warm it to 60-70⸰C and titrate against KMnO4 from the burette till light
pinkish colour appears. Repeat the titration until concomitant result are
obtained the strength of KMnO4 is calculated using the formula
N1V1=N2V2 where N1= Normality of KMnO4 ?
V1= Volume of KMnO4 Solution used
N2= Normality of standard oxalic acid solution
V2= Volume of standard oxalic acid solution
• Note: Ordinary or even pure distilled water contains traces of organic
matter which reduces the KMnO4 solution. That is why the solution is
boiled and kept for some time before standardization. In the absence of
sufficient amount of dilute H2SO4 or due to the time rapid addition of
KMnO4 in titration brown turbidity may appear.
44

45. 4) Sulphuric Acid:
Preparation of 0.1N H2SO4
Equivalent weight of H2SO4= 49
Specific gravity = 1.84 g/ml
So volume of 49 g H2SO4 = 26.6 ml
Concentrated H2SO4 is about 97% pure
Therefore actual amount of Concentrated H2SO4 required for 1 lit of 1N
H2SO4 solution is = (100/97)×26.6 = 27.42
For 1 lit 0.1N H2SO4 solution, 2.74 ml of Concentrated H2SO4 required
Procedure
Take 2.74ml sulphuric acid in beaker filled with small amount of
distilled water. Transfer the contents of beaker to volumetric flask of 1
lit capacity and make volume up to the mark with distilled water. Shake
well.
45

46. Standardization
• 0.1N H2SO4 is titrated with 10ml of 0.1N Na2CO3 using methyl orange as
an indicator. Repeat the titration until at least three concordant readings
are obtained
• Suppose 10ml of 0.1N Na2CO3 = 9.5 ml of H2SO4
N1V1=N2V2
10×0.1=9.5×N2
N2 = 0.1052
To prepare 1 lit 0.1N H2SO4 the volume of 0.1052 N acid required is
1000×0.1= 950ml
0.1052
Take 950ml 0.1052 N acid and dilute to 1 lit.
46

47. 5) Hydrochloric Acid:
Molar mass of HCl is 36.46g/mol, since HCl has only one hydrogen, the
equivalent mass will be 36.46. Specific gravity for 1 lit. volume of HCl is
1.189
For 1 lit. volume, grams of compound needed = (0.1N)(36.46)(1lit)=3.6461
Volume of concentrated (37.5%) needed= 3.6461 =8.1774ml
0.375×1.189
Procedure
Transfer exactly 20ml of the 0.1M HCl solution into 250ml conical flask. Add
3 drops of phenolphthalein as indicator. Titrate against standard 0.1N NaOH
solution until a permanent pale pink colour is appeared. Using the volume of
NaOH, the strength HCl is calculated.
HCL can be standardized by titrating with standard 0.1N Na2CO3 using
methyl orange as indicator, colour change yellow to reddish orange.
47

48. Standardization
• HCl is standardized against 0.1N NaOH which is already standardized
against 0.1N oxalic acid using phenolphthalein indicator.
HCl + NaOH → NaCl + H2O
6) Sodium Thiosulphate:
Preparation of 0.1M Sodium Thiosulphate Solution (Na2S2O3.5H2O):
Dissolve 24.8gm of sodium thiosulphate crystal in previously boiled and
cooled distilled water and make the volume to 1000ml.
Store the solution in a cool place in a dark colored bottle.
After storing the solution for about two weeks, filter if necessary and
standardize as follows:
48

49. Standardization
• Weigh accurately about 5 gm of finely ground potassium
dichromate which has been previously dried to a constant weigh
about at 105+2⸰C into a clean 1 lit. volumetric flask.
• Add distilled water to dissolve the content of volumetric flask and
make up to the mark with distilled water shake thoroughly and
keep in dark place.
• Pipette 25 ml of this solution into 250ml conical flask. Add 5ml
concentrated HCl and 15ml of 10% potassium iodide solution.
Allow to stand for 5 min and titrate the mixture with the solution
of sodium thiosulphate using starch solution as an indicator
towards the end point.
• The end point taken when blue colour changes to green. Calculate
the Normality of the Sodium thiosulphate.
49

50. 7) Ceric Ammonium Sulphate:
Preparation of 0.1M Ceric Ammonium Sulphate:
Dissolve 66gm of ceric ammonium sulphate with gentle heat in a mixture of 30ml of
sulphuric acid and 500ml of water. Cool the mixture, filter and dilute to 1000ml with
water.
Standardization of 0.1M ceric Ammonium sulphate:
Arsenic trioxide is allowed to dry for an hour. From this weigh about 20.2gm of arsenic
trioxide accurately and transfer into 500ml conical flask. Wash the inner walls with of
conical flask with 100ml of water and mix thoroughly. To this , add 300ml of dilute
sulphuric acid ,0.15ml of osmic acid and 0.1ml of ferroin sulphate indicator.
Titrate this solution with ceric ammonium sulphate which has taken in burette. Continue
the titration till the pink colour of solution changed to pale blue or yellowish green
colour.
Each ml of 0.1n ceric ammonium sulphate≅ 0.6326 gm of ceric ammonium sulphate
≅4.946 gm of arsenic trioxide
50

51.  DEFINITION:
• Errors may be defined as the difference between a measured value and its true value.
• True value of a measurement is determined by taking the mean value of a series of repeated
measurements.
 TYPES OF ERRORS:
• Errors are classified in two types
I. Systemic (Determinate) errors
II. Random (Indeterminate) errors
A) DETERMINATE ERRORS:
• Errors which can be avoided or whose magnitude can be determined is called as systemic
errors. It can be determinable and presumably can be either avoided or corrected.
ERRORS
51

52. 52
Systemic errors further classified as:
1. Operational and personal error
2. Instrumental error
3. Errors of method
4. Additive or proportional error
1. Operational and personal error:
• Errors for which the individual analyst is responsible and are not connected with the method
or procedure is called as personal errors.
• We can assign indeterminate errors to several sources, including collecting samples,
manipulating samples during the analysis, and making measurements.
e.g. unable to judge colour change when errors occur during operation is called as operational
error e.g. transfers of solution, effervescence, incomplete drying, underweighting of precipitates,
overweighing of precipitates, and insufficient cooling of precipitates.
These errors are physical in nature and occur when sound analytical techniques is not followed

53. 53
2.Instrumental and Reagent errors:
Errors occur due to faulty instrument or reagent containing impurities.
e.g. un-calibrated weights, un-calibrated burette, pipette and measuring flasks.
3.Errors of Method:
When errors occur due to method, it is difficult to correct. In gravimetric analysis, error
occurs due to Insolubility of precipitates, co- precipitates, post-precipitates, decomposition,
and volatilization.
In titrimetric analysis errors occur due to failure of reaction, side reaction, reaction of
substance other than the constituent being determined, difference between observed end
point and the stoichiometric equivalence point of a reaction.

54. 54
4. Additive or proportional errors:
• Additive error does not depend on constituent present in the determination e.g. loss in weight
of a crucible in which a precipitate is ignited.
• Proportional error depends on the amount of the constituent e.g. impurities in standard
compound.
B)INDETERMINATE ( Random )ERRORS :
• These errors are also called accidental errors. Indeterminate errors arise from uncertainties in
a measurement that are unknown and which cannot be controlled by the analyst.
• Random error is caused by unpredictable fluctuations in the readings of a measurement
apparatus or experimenters interpretation of the instruments reading.

55. MINIMIZATION OF ERRORS:
Analyst has no control on random errors but systemic errors can be reduced by following
methods.
(I) Calibration of Instruments, Apparatus and Applying Necessary Corrections:
• Most of the instruments, commonly used in an analytical laboratory, such as : UV-
Spectrophotometer-meter, IR- Spectrophotometer, single—pan electric balance, pH-meter,
turbidimeter and nephelometer, Polari meter, refractometer and the like must be calibrated
duly, before use so as to eliminate any possible errors.
• In the same manner all apparatus, namely : pipettes, burettes, volumetric flasks,
thermometers, weights etc., must be calibrated duly, and the necessary corrections
incorporated to the original measurements in some specific instances where an error just
cannot be avoided it may be convenient to enforce an appropriate correction for the effect
that it ultimately causes for instance : the inherent impurity present in a weighed precipitate
can be estimated first and then deducted duly from its weight.

56. II) Performing a Parallel Control Determination:
• It essentially comprises of performing an altogether separate estimation under almost
identical experimental parameters with a quantity of a standard substance that consists of
exactly the same weight of the component as is present in the unknown sample.
• Thus, the weight of the component present in the unknown sample may be calculated with
the help of the following expression :
Result found for standard
× Weight of constituent in standard
Result found for unknown X
Where, X = Weight of the component present in the Unknown sample.

57. (III) Blank Determination :
• In order to ascertain the effect of the impurities present in the reagents employed and reaction
vessels used, besides establishing exactly the extent to which an excess of standard solution
required to locate the exact end-point under the prevailing experimental parameters of the
unknown sample—a blank determination is an absolute necessity.
• It may be accomplished by performing a separate parallel estimation, without using the sample
at all, and under identical experimental parameters as employed in the actual analysis of the
given sample.
• Note : Always avoid using an appreciably large blank correction which gives rise to a vague
and uncertain ‘exact value’ thereby minimizing the precision of the analysis.

58. (IV) Cross-checking Results by Different Methods of Analysis:
In certain specific cases the accuracy of a result may be cross-checked by performing another
analysis of the same substance by an altogether radically different method.
Examples :
(a) HCl-Solution : It may be assayed either by titration with a standard solution of a strong
alkali (NaOH), or by precipitation
(b) In water hardness the calcium and the magnesium conc. Determine by atomic absorption
may be compared with the results obtained by complexometric titration (EDTA titration )
In short, the results thus obtained by the two fundamentally different techniques must be
concordant thereby justifying and ascertaining the fact that the values obtained are fairly
small limits of error.

59. (V)Method of Standard Addition:
• Here, a small known quantity of the component under estimation is added to the sample, which
is subsequently subjected to analysis for the total amount of component present.
• The actual difference in the quantity of components present in samples with or without the
added component ultimately gives the recovery of the amount added component.
• A goods at is factory recovery builds up the confidence in the accuracy of the method of
analysis.
Note : The method of ‘standard addition’ is particularly useful to physicochemical techniques
of analysis, for instance : Spectrophotometry, Turbidimetry.
(VI) Method of Internal Standards:
• The specific method is of immense value both in chromatographic as well as spectroscopic
determinations.
• Here, a fixed quantity of a reference substance (i.e., the ‘internal standard’) is added to a series
of known concentrations of the material to be assayed.
• The ratio of the peak size of the internal standard and the series of known conc are plotted
against the conc. values. This should give straight line.

60. Absolute Error
The absolute error is the difference between the measured value and the actual
value. (The absolute error will have the same unit label as the measured quantity)
E absolute = I X(measured) – X(accepted) I
Relative Error:
Relative error is the ratio of the absolute error of the measurement to the accepted
measurement.
E relative = [measured value- actual value]/actual value
Percent of Error:
Error in measurement may also be expressed as a percent of
error. The percent of error is found by multiplying the relative error by 100%.
E % = [measured value- actual value]/actual value x 100

61. 61
Sources of Impurities in Pharmaceuticals
 Impure Chemical Compound:
• Acompound is said to be impure if it is having foreign matter i.e. Impurities.
 Pure Chemical Compound:
• A pure chemical compound refers to that compound which is having no foreign matter
i.e. impurities.
• Chemical purity means freedom from foreign matter.
• Analytically 100 % pure substances are not available and traces of impurities must be present.
• Impurity is any material that affects the purity of the material of interest.
• Presence of Impurities in the pharmaceutical substances may produce toxic effects on the
body and may also lower down the active strength of the pharmaceutical substance.
• Impurities commonly in chemical substances include small quantities of lead, Arsenic,, Iron,
Chloride and sulphate.

62. 62
Sources of Impurities in Pharmaceuticals
The different sources of impurities in pharmaceuticals are listed below:
1)Raw material used in manufacture
2)Reagents used in manufacturing process
3)Method/ process used in manufacture or method of manufacturing
4)Chemical processes used in the manufacture
5)Atmospheric contamination during the manufacturing process
6)Intermediate products in the manufacturing process
7)Defects in the manufacturing process
8)Inadequate Storage conditions
9)Decomposition of the product during storage
10) Accidental substitution or deliberate adulteration with spurious or useless
materials

63. 63
1) Raw materials employed in manufacture
• When substances or chemicals are manufactured the raw materials from
which these are prepared often contain impurities. These impurities get
incorporated in final product
• Example – Impurities like arsenic, lead, heavy metal etc., are present in
raw material and are found in final product.
• Impurities such as Arsenic, Lead and Heavy metals are present in raw
materials and hence are found in substances. So, it is necessary to use
pure chemicals and substances as raw materials for the manufacturing
process.

64. 64
HgCl2+ 2NH4OH-------------NH2HgCl + NH4Cl + 2 H2O
Soluble soluble Ammoniated mercury (ppt) (soluble)
2) Reagents used in the manufacturing process:
• If reagents used in the manufacturing process are not completely removed by
washing, these may find entry into the final products.
• Example:
Ammoniated mercury may be prepared by adding a solution of Mercuric chloride to dilute
ammonia solution.
The precipitate ofAmmoniated mercury (Final Product)contains ammonium hydroxide.Thus,
this precipitate is washed with cold water to remove ammonium hydroxide.
If it is not removed completely by washing with water, the final product may
contain in it Ammonium hydroxide as impurity.

65. 65
3) Method or the process used in the manufacture:
• Many drugs and chemicals (usually organic) are manufactured from different raw
materials, by using different methods or processes.
• Some impurities are incorporated into the materials during the manufacturing process.
• The type and amount of impurity present in the drug/ chemical varies.
• In certain drugs , a multiple-step-synthesis procedure is used , which produces
• intermediate compounds.
• The purification of intermediates is also important, otherwise the impurities present in
the intermediate will get incorporated in the final product.
• Usually side reactions occur during the synthesis. Impurities of the product side
reactions also occur in the substances.

66. • This may introduce new impurities due to contamination by reagents and solvents at various
stages of the process as described below:
 Reagents employed in the process:
i.e. Calcium carbonate is obtained by interaction of a soluble calcium salt and a soluble carbonate and
therefore the product will contain traces of soluble alkali, which the washing process has failed to remove.
 Reagents added to remove other impurities
i.e. Potassium bromide contains traces of Barium, which is added in the manufacturing process to remove
excess of sulphate.
 Solvents
i.e. Water is the cheapest solvent available and has been used wherever possible
 Action of solvents and reagents on reaction vessels
• During manufacturing process, some of the solvents and reagent may undergo reaction with metals of
reaction vessel and may dissolve these metals, which appear as impurities in the final product.
• i.e. The inorganic compounds manufactured in Iron vessel will containArsenic and Iron as impurities.
• Thus IP has prescribed limit test forArsenic and Iron for most inorganiccompounds
66

67. 4) Chemical process used in the manufacture:
 For the synthesis of drugs, many chemical reactions such as Nitration,
Halogenation, Oxidation, reduction, hydrolysis are involved.
 In these chemical processes, different chemicals are used.
 Tap water is generally used in the various processes and it is often having
Cl-,Mg+2, Ca+2 ions, which are generally found in the substance which is
being manufactured.
67

68. 5)Atmospheric contamination during the manufacturing process:
• In the industrial areas, the atmosphere is contaminated with dust particles and
• some gases like Hydrogen sulphide, Sulphur dioxide, and black smoke.
• During the manufacture or purification of the pharmaceutical products, these
impurities enter the final products.
• There are many pharmaceutical products which when manufactured are
contaminated with atmospheric CO2 and water vapour.
Example - NaOH absorbs atmospheric CO2.
• 2NaOH + CO2 -------------------------------- Na2CO3 + H2O
• Due to this reaction, NaOH should not be kept open for a longer time during its
• manufacture.
• Therefore, IP has prescribed that Sodium hydroxide should not contain more than 3% of
sodium carbonate.
68

69. 6) Defects in the manufacturing process:
• In many manufacturing processes, there are defects like imperfect mixing,
incompleteness, non-adherence to proper temperature, pressure, pH or reaction
conditions, which may give chemical compounds with impurities in them.
• Example:
• Zinc oxide may be prepared by heating metallic zinc to bright redness in a current of
air. The vapours of Zinc burn to form Zinc oxide which is collected as a fine white
powder.
• But if there is less heat or air or both, zinc metal is not completely converted to
zinc oxide.
• Thus the final product, Zinc oxide may still contain metallic zinc as impurity.
• So, IP has prescribed a test for Zinc metal in zinc oxide.
69

70. 7) Intermediate products in the manufacturing process:
• There are some intermediates which are produced during the manufacturing
process.
• Sometimes these intermediates may be carried through to the final product as
impurity.
Example:
Potassium iodide is prepared by reacting Iodine with Potassium hydroxide.
6KOH+ 3I2--------------------5KI + KIO3 + 3H2O
• The resulting solution is first evaporated and then heated with charcoal.
KIO3 + 3C-------------------KI + 3CO
• In this process if the intermediate product (KIO3) is not completely converted into
KI, then it may be carried through to the final product as an impurity.
70

71. 8) Storage conditions:
• The chemical substances when prepared have to be stored in different types of containers
depending upon:
 Nature of the material
 Batch size
 Quantity
• Many types of materials are used for storage purpose like plastic, polythene, iron vessels,
stainless steel and aluminum copper etc.
• Reaction of these substances with the material of the storage vessel takes place and the
products formed occur as impurities in the stored material.
Examples-
• Leaching out effect: Alkalis stored in ordinary glass containers extract lead from it, which
in found as impurity in the final product.
• Strong chemicals react with iron containers and extract Iron an impurity in final product.
71

72. 10) Decomposition of the product during storage:
• Chemical decomposition, analysis or breakdown is the separation of a chemical
compound into elements or simpler compounds.
• It is sometimes defined as the exact opposite of a chemical synthesis. Chemical
decomposition is often an undesired chemical reaction.
• Some substances decompose on storing due to presence of air, light and oxygen. So,
the final product is contaminated.
• Deliquescent substances, absorb water from the atmosphere and get liquefied.
• Crude vegetable drugs are especially susceptible to decomposition.
• A number of organic substances get spoiled because of decomposition on exposure to
the atmosphere. e.g. amines, phenols potent drug etc.
• Decomposition products appear as impurities in the substances.
72

73. 11)Accidental substitution or deliberate adulteration with spurious or
useless materials:
• It is possible to avoid accidental substitution by storing the toxic
substances together
• separately or in a locked cupboard.
• Many pharmaceutical chemicals are adulterated with cheaper substances.
• E.g The expensive potassium may be adulterated with sodium bromide
73

74. Effect of Impurities
The impurities present in the substances may give following effects:
1. Impurities having toxic effects may be injurious to health, if present above
certain limits.
2. Traces of impurities may exert a cumulative toxic effect after a certain time.
3. Impurities may lower the active strength of the substance.
4. Impurity may decrease shelf life of substance.
5. Impurity may cause incompatibility with other substances.
6. Impurities may cause a physical or chemical change in the properties of the
substance, so making the substance medicinally useless.
7. May cause change in color, odour and taste.
74

75.  Pharmacopoeia of various countries prescribe “Test for purity” for substances
which are to be used for medical purpose. The so called tests for purity are as a
matter of fact tests for detecting impurities in the substances.
 Pharmacopoeia will decide and fix the limit of tolerance for these impurities.
 For certain common impurities for which pharmacopoeia prescribes the test of
purity are:
 Colour, odour, taste:- Along with other test for purity, description of test, odour,
colour, etc., are given in pharmacopoeias.
 Physicochemical constants :- Solubility of the substances in various solvents ,
determination of melting and boiling points for organic substances, optical rotation
for optically active substances and refractive index for liquids are some values which
tell us about the purity of substances.
75
Test for purity:

76.  Acidity, alkalinity, pH:- Substances that are prepared from chemical reaction involving
acids and alkalis often contain considerable amount of the acid or alkali, as an impurity.
So the tests for acidity and alkalinity are of a great help to estimate the extent of the
impurity.
• Solution of certain substances have a definite pH at a given conc. The presence of an
impurity will bring change in pH and it can be detected.
 Cations and anions:- A large number of synthetic drugs both inorganic and organic is
prepared using strong acids like hydrochloric, nitric, sulphuric, etc.
• The presence of chloride and sulphate ions are common impurities. Test for these ions
(anions) generally carried out.
• Test for sodium , ammonium (cations) are often carried out to detect impurities in
inorganic compounds.
• Tests for heavy metals like lead, iron, copper and mercury are also carried out as these
are very common impurities in substances.
 Ash:- Determination of ash in crude vegetable drugs , organic compound and some
inorganic compounds give good indication about the extent of impurities of heavy
metals or minerals in nature.
76

77. Validation Parameters of analytical methods
Validation: A process involving confirmation of establishing by laboratory studies that a
method/procedure/system/analyte give accurate and reproducible result for intended analytical
application in a proven and established range is called validation.
Analytical parameters to be validated:
1) Accuracy
2) Precision
3) Repeatability
4) Reproducibility
5) Intermediate precision
6) Selectivity (specificity)
7) Linearity and range
8) Sensitivity
9) Limit of detection
10) Limit of quantitation
11) Ruggedness
12) Robustness
77

78. • Accuracy:
• It relates to the closeness of test results to true ( actual ) value. i.e measure of
exactness of analytical method.
• It is expressed as % recovery by the assay of known added amount of analyte in the
linearity range. This is probably most difficult parameter to validate.
• Accuracy of the method can be determine in one of three ways
a) Recovery study
b) Comparison with results using another method known to be accurate
C) Analysis of reference material
• Recovery studies are performed by adding a known amount of the analyte either to
blank matrix or by adding a sample in which the background analyte is measured
by the same procedure and subtracting from the total value to obtain recovery.
• A better validation is to perform the analysis by two independent methods in which
the second method is known to be accurate for the sample matrix of interest
• The ideal way to validate a method is to analyse a reference material in composition
to given sample.
78

79. • Precision:
• Precision may be defined as the degree of agreement between the replicate
measurements of the same quantity.
• The precision is usually expressed as
• Standard deviation
• Relative standard deviation
• Repeatability: Repeatability is the precision of the method when repeated by the same
analyst using same test method and under same set of laboratory conditions within a
short interval of time, deference being the sample analysed.
• Reproducibility: when the subject method is carried out by different analyst in
different laboratories, using different equipments, reagents and laboratory setting
and on different days using the sample for same then the study carried out is
reproducibility study.
• Intermediate precision: Precision of the method when repeated in same laboratory.
Different days, different analyst, different equipment, different reagent lots etc.
79

80. 15

81. • Selectivity (specificity):
• Selectivity is the extent that the method can measure the analyte of interest in the matrices of
the sample being analysed without interference from matrix (including other analyte)
• The method must allow distinct analytical measurement of analyte of interest and exclusion of
all other relevant interferences.
• Linearity and range:
• The linearity of an analytical method is its ability to obtain test result that are directly
proportional to the concentration of analyte in samples.
• Range: Lowest and highest level of analyte that the method can determine with reasonable
accuracy and precision in the range of 80/100/120% of the claim.
• Linearity and range may be demonstrated directly one the test substance and or by using separate
weighing or synthetic mixture of the test product components, using proposed procedure.
• Sensitivity:
• The sensitivity is the ability to differentiate two different concentration and is determined by
the slop of the calibration curve.
• Sensitivity is the slop of the calibration curve that is obtained by the response against the
analyte concentration.
81

82. • Limit of detection (LOD): it is defined as the lowest conc. of analyte in sample that can
be detected but not necessarily quantify under stated experimental condition.
• Limit of quantitation (LOQ): it is defined as the lowest conc. of the analyte in a
sample that can be estimated quantitively with acceptable precision, accuracy and
reliability by a given method under stated experimental condition.
• Ruggedness: refer to the precision of test result obtain by analyse the same sample
under Varity of normal test condition such as laboratories, analysts, instruments,
days, reagents.
• Ruggedness is a measure reproducibility of test results under normal expected
operational conditions from laboratory to laboratory and from analyst to analyst.
• Study will identify those factor that will contribute to variability of the results and should
not be changed.
• Robustness: Robustness or reliability refer to how sensitive the method is to control
small change in parameters such as the size of sample, temperature, pH of the
solution, reagent of concentration, time of reaction.
• It is the measure the capacity of the analytical method to remain unaffected by small but
deliberate variation in procedure.
82

83. Sampling techniques:
• Sampling: Sampling is withdrawal of small portion from bulk which is
truly representative of whole bulk material.
• Sample Preparation: the problem involves obtaining a sample that is
representative of the whole. This sample is called the gross sample.
• Its size very from a few gram or less to several pound, depending of the
type of bulk material.
• Once gross sample is obtained it may have to reduced to a sufficiently small
size to be handled. This is called sample.
• Once sample is obtained an aliquot, or portion of it will be analysed, this
aliquot is called the analytical sample.
• Several replicate analyses on the same sample may be performed by taking
separate aliquots.
83

84. 1) Sampling techniques for solid compound:
• In homogeneity of the material, variation in particle size, and variation
within the particles make sampling of solid more difficult than other
material.
• The easiest but usually most unreliable way to sample a material is the grab
sample which is one sample taken at random and assumed to be
representative.
• The grab sample will be satisfactory only if the material from which it is
taken is homogeneous.
2) Sampling techniques for liquid compound:
• These material tend to be homogeneous and are much easier to sample.
Liquid must be shaken to obtain a homogeneous mixture.
• If mixture is indeed homogeneous a simple grab sample will suffice. For all
practical purpose this method is satisfactory for taking blood samples.
84

85. • If liquid samples are not homogeneous and if they are small enough they can be
shaken and sample immediately. Example they may be particles in the liquid that
have tend to settle.
• Large stationary liquids can be sampled with thief sampler which is device for
obtaining aliquots at different levels.
• The separate aliquots of liquids can be analysed individually and the result obtained,
or the aliquots can be combined into one gross sample and replicate analyses
performed.
3) Sampling techniques for gaseous compounds:
• The usual method of sampling gases involves displacement of a liquid. The liquid
must be one in which the sample has little solubility and with which it does not
react.
• Mercury is the liquid is allowed to trickle from the bottom of the container,
whereupon the gas is pulled in at the top.
• A grab type sample is satisfactory in some cases. In the collecting of breath sample.
• Example- the subject could blow into an evacuated bag . Auto exhaust could be
collected in large evacuated plastic bag.
85

86. Sampling error minimization:
1) By increasing the size of the sample:
The sampling error can be reduced by increasing the sample size. If the sample size n is
equal to the population size N, then the sampling error is zero.
2) By stratification:
When the population contains homogeneous units, a simple random sample is likely to
be representative of the population. But if the population contain dissimilar units, a
random sample may failed to be representative of all kinds of units, in the population.
To improve the result of the sample, the sample design is modified. The population is
divided into different groups containing similar units this groups are called strata.
From each group a sub sample is selected in a random manner. Thus all groups are
represented in the sample and sampling error is reduced. It is called stratified
random sampling.
The size of sub sample from each stratum is frequently in proportion to the size of
the stratum.
86

87. 1) Define and classify errors? Describe the various methods to minimize theerrors.
2) What are different methods of expressing concentration?
3) What are primary and secondary standards? Give examples of primary standards used in different
types of titrations. Enlist the ideal properties ofthe primary standard.
4) How do you calculate the equivalent weight and molecular weight of asubstance. Give examples.
5) What is pharmaceutical analysis? Explain different types of analysis. What is its scope in
pharmacy?
6) What is sampling? Discuss sampling techniques.
7) Explain: Validation, Accuracy, Precision, Limit of Detection, Limit of Quantitation,
8) Explain: Specificity, Selectivity, Ruggedness, Robustness, Repeatability, Reproducibility,
Intermediate precision, Linearity and range.
9) Discuss various sources of impurities, effect of impurities, and test for purity.
10) What is analytical method validation? Enumerate validation parameters and define any four.
11)Give the importance of quality control and quality assurance in formulation analysis.
12)Define limit test. Write a principle and reaction of limit test for chloride, iron, arsenic, lead, and
sulphate
87

88. Thank you
88