1. Pharmaceutical Analytical Chemistry-1 (PHC 103)
The 100 marks of this Course is divided into:
Midterm : 10 marks
Online Quizes : 5 marks
Attendance and behavior : 5 marks
Practical exam : 20 marks
Oral exam : 10 marks
Written final exam : 50 marks

2. Quantitative analysis
It deals with the determination of the quantity of the substance to be analyzed (concentration).

3. Classification of quantitative analysis according to the quantity measured
Macro-analysis
100 mg and more
Semi-micro – analysis mg
Micro-analysis
not exceeding 1 mg

4. Classification of quantitative analysis according to the physical state of the substance to be analysed
e.g. gas analysis, when the substance to be analyzed is available in gaseous state.

5. Classification of quantitative analysis according to the process of measurement
Volumetric analysis
Gravimetric analysis
Instrumental methods of analysis
Ionic combination reactions
Electron transfer reactions
Redox reactions
Neutralization reactions
Complexation reactions
Formation of weakly ionisable salt
Formation of water
Displacement titration
Formation of weak acid
Formation of weak base

6. Classification according to the process of measurement
1- Volumetric analysis (titration)
depends on measuring the volume of the analyzed sample and the volume of standard solution used for complete reaction,
OR measuring the capacity of the sample to combine with the standard quantitatively
2- Instrumental method of analysis (physico-chemical methods)
depends on measuring optical or electrical properties which are quantitatively related to the analyzed sample concentration.
3- Gravimetric analysis
depends on weighing the final product of reaction after its isolation in pure and stable form of definite chemical structure.

7. Requirements of titrimetric reactions:
The reaction must be simple and expressed by a chemical equation.
A single reaction must occur between the sample and titrant as described by a chemical equation.
The reaction must be instantaneous (rapid).
Suitable standard solution must be available.
The end point should be easily detected.

8. A quantitative reaction
N.B.
A quantitative reaction
reaction that proceeds forward to produce stable product(s) such as weakly ionizable compounds, e.g. H2O, weak acid, weak base, sparingly soluble salts (precipitate), complex ion, …
I- Ionic combination reactions:-
- The reaction goes to completion due to formation of slightly ionizable
or slightly insoluble products.
a- Neutralization reaction :
In which acid reacts with base to form slightly ionized water.
H+ + OH H2O
b- Formation of precipitate :
Ag+ + Cl AgCl ↓
Ba+2 + SO BaSO4 ↓

9. c- Formation of slightly ionizable complex :
Ag+ + 2 CN [Ag(CN)2]-
Ca+2 + H2Y-2 [EDTA] H+ + CaY-2 [Ca-EDTA complex]
II- Electron transfer reactions :
In which electron transfer from one reactant to another.
It is called (oxidation -reduction reactions)
Ce+4 + Fe Ce+3 + Fe+3
i.e. Fe Fe+3 + e oxidation (loss of electron)
Ce+4 + e Ce+3 reduction (gain of electron)
Standard Solutions
They are solutions of exact, known concentration. They are classified according to the type of concentration into molar, normal and empirical solutions.

10. 1. Molar solution (M)
It is a solution of known concentration, each liter contains the gram molecular weight or its fractions or multiples.
e.g.
Molecular weight (M.wt) / liter (L), it is expressed as 1M or M
½ M.wt /L, it is expressed as M/2 or 0.5M.
4 M.wt/L, it is expressed as 4M.

11. 2. Normal solution (N)
It is a solution of known concentration, each liter contain the gram equivalent weight (eq.wt) or its fractions or multiples.
e.g.
eq.wt/L, it is expressed as 1N or N solution.
0.1eq.wt/L, it is expressed as 0.1N or N/10 solution.
3 eq.wt/L, it is expressed as 3N solution.

12. How to Calculate the equivalent weight ?
Acids
Eq.wt = (M.wt )/ number of replaceable hydrogen
HCl eq.wt = M.wt / 1
H2SO4 eq.wt = M.wt / 2
Bases
Eq.wt = (M.wt )/ number of replaceable hydroxyl ion
NaOH eq.wt = M.wt / 1
Ba(OH)2 eq.wt = M.wt / 2
Salts
Eq.wt = M.wt / number of cations x its valency
Or =M.wt / number of anions x its valency
Na2SO4 eq.wt = M.wt / 2 x 1 or M.wt / 1 x 2

13. 3. Emperical solution
It is a solution of known concentration, prepared in such a way that 1ml of it reacts with a definite amount of the analyzed substance. It is used for determination of one substance only. (used for routine analysis)
e.g. empirical standard AgNO3, 1ml of it reacts with g. NaCl.
AgNO3 + NaCl  AgCl + NaNO3
M.wt AgNO3 = M.wt NaCl
170 gm AgNO3 = 58.5 gm. NaCl
x = gm NaCl
x = x 170 / 58.5 = gm AgNO3
i.e. each 1ml empirical AgNO3 should contain gm AgNO3 to be equivalent to gm NaCl.

14. Standard solution is classified into: 1- Primary standard chemicals
Primary standard chemicals are substances of definitely known composition and high purity.
They must fulfill the following requirements:
Easily available in high purity and known composition.
Easily tested for impurity.
Stable, i.e. not absorbing water or CO2 from air, non volatile and withstand drying at oC.
Must react with other substances quantitatively according to a balanced chemical equation (react stoichiometrically).
Readily soluble in the solvent.
Having high equivalent weight to minimize error during weighing.
Examples of primary standard chemicals:
Potassium hydrogen phthalate (KHC8H4O4),
benzoic acid (HC7H5O2), Primary standard acid
constant-boiling-point hydrochloric acid,
anhydrous sodium carbonate (Na2CO3),
anhydrous potassium bicarbonate (KHCO3) Primary standard base
mercuric oxide (HgO).

15. 2- Secondary standard chemicals:
Secondary standard chemicals are substances which may be used for standardization and whose content have been found by comparison against primary standard.
e.g.
HCl,
NaOH,
borax (Na2B4O7.10H2O) and
oxalic acid (H2C2O4.2H2O).

16. Preparation of standard solutions
a. Direct method:
An accurately weighed amount of the solute is transferred into a volumetric flask, dissolved in the solvent then completed to the required volume and mixed well. The solute must be a chemical of primary standard quality.
b. Indirect method:
If the solute is not primary standard, prepare solution of approximate concentration (approximate standard), which must be standardized against primary standard solution.

17. The standardization factor (f)
f = volume of exact standard / volume of approximate standard
It ranges from , out this range the solution is not of expected strength.
The volume of secondary standard must be multiplied by its standardization factor (f) to obtain the volume of exact normality or molarity.
Calculation of equivalent factor (F)
It is how much of sample substance is equivalent to 1ml standard.
Finally, calculation of sample concentration
- Concentration of sample solutions in gm/L
= Volume of exact standard consumed x f x Equivalent factor (F) x 1000
Volume of the Sample
In case of powdered sample (solid), - Concentration of sample g %
= Volume of exact standard consumed x f x Equivalent factor (F) x100
wt. of sample