Analytical techniques

Analytical
Techniques
By
Dr. Sachin M. Hiradeve
Associate Professor
Nagpur College of Pharmacy, Nagpur

Introduction to Analysis
Pharmaceutical analysis is defined as a branch of chemistry, which involves the series of process for the identification,
determination, quantitation, and purification.
Based upon the determination type, there are mainly two types of analytical methods. They are as follows:
a. Qualitative analysis: This method is used for the identification or recognition of the chemical compounds by means of:
• Colour, taste, viscosity and solubility
• Reaction producing a colour
• Reaction producing a precipitate
• Reaction involving a change of a physical parameter.
b. Quantitative analysis: This method is used for the determination of the amount of the sample. Also the quantitative chemical
analysis carried out by determining the volume of a solution of accurately known concentration which is required to react
quantitatively with a measured volume of the substance to be determined.

Different Techniques of Analysis

Titration Techniques
• It is based on the complete chemical reaction between the analyte and
the reagent (titrant) of known concentration.
• Analyte + Titrant → Product
• Terms used in titration
• Analyte:- Unknown concentration of solution
• Titrant:- The solution of known concentration.
• Standard solution:- A solution of known concentration is called the
standard solution.

Types of standard solution
• Primary standard
• Extremely pure.
• Highly stable.
• Can be weighed easily.
For e.g. Na2CO3, KHP
• Secondary standard:-
• Less pure than primary standard.
• Less stable than primary standard.
• Can not be weighed easily.
For e.g. NaOH, HCl

• Euivalence Point:- Point where the amount of two reactants are just equivalent .
• End point:- Point at which the reaction is observed to be complete, this point is
usually observe with the help of indicator.
• Indicator:- An auxiliary substance which helps in the usual detection of the
completion of the titration process at the end point.
• For examples:- Methyl orange, Phenolphthalein, Cresol red, Thymol blue.

• Concentration Terms:-
• The concentration of standard solutions
• (titrants) are generally expressed in units of either molarity (CM, or M) or normality (CN,
or N).
• Molarity (M):-It is the number of moles of a solute per liter of solution.
• Normality:- It is the gram equivalent weight of solute dissolved per litre of solution.
• Molality:- It is the number of moles of solute present in per kilogram of solvent.

Titrimetric calculation :-
It is based on the following law of equivalence:-
NaVa =
or
NsVs
MaVa = MsVs
Where, Na is the normality of analyte.
Vais the volume of the analyte.
Ns is the normality of standard solution.
Vs is the volume of standard solution used.
Ma is the molarity of analyte.
Ms is the molarity of standard solution.

Titrimetric apparatus :-

Instrumental methods
Spectroscopy
Spectroscopy measures the interaction of
the molecules with electromagnetic
radiation. Spectroscopy consists of many
different applications such as atomic
absorption spectroscopy, atomic emission
spectroscopy, ultraviolet-visible
spectroscopy, x-ray fluorescence
spectroscopy, infrared spectroscopy,
Raman spectroscopy, dual polarisation
interferometry, nuclear magnetic
resonance spectroscopy, photoemission
spectroscopy, Mössbauer spectroscopy
and so on.
Block diagram of an analytical instrument showing
the stimulus and measurement of response

Summary of the spectroscopic Techniques
Radiation Absorbed Effect on the molecule of the substance and information
obtained
Ultra-violet (190-400 nm) and
Visible (400-800 nm)
Changes in electronic energy levels within the molecule,
conjugated unsaturation, conjugation with non-bonding
electrons, extent of π electron system.
Infra-red
667-4000 cm-1
Changes in the vibrational and rotational movements of the
molecule. Detection of almost all functional groups which has
specific vibrational frequencies such as C=O, O-H, NH2 etc.
Radio-frequency
Frequency 60-300 MHz
Nuclear magnetic resonance, induces changes in the
magnetic properties of certain atomic nuclei, notably that of
hydrogen. Hydrogen atom that of different environments can
be detected, counted and analysed for structure
determination
Electron Beam Impact
70 eV, 6000 kJ/mol
Ionisation and fragmentation of the molecule into a spectrum
of fragment ions (determination of molecular weight and
deduction of molecular structure from the fragments
obtained)

UV Spectra of Isoprene

Mass Spectrum

NMR Spectrum

INTRODUCTIONTO
CHROMATOGRAPHY
ANDITSAPPLICATIONS
1

Introduction
Chromatography, literally "color writing",
was first employed by Russian-Italian
scientist MikhailTsvetin 1900, primarily for
the separation of plant pigments such as
chlorophyll, carotenes, andxanthophylls.
Theword chromatography is derivedfrom
two Greekwords
Chroma….……..color
Graphos………..writing
2

Definition
‘A technique by which a mixture isseparatedinto its
components on the basisof relative ability of each
component to bemoved along/through astationary
phaseby mobilephase’
The technique of chromatography is based on the
differences in the rate at which the components of a
mixture move through aporous medium (called
stationary phase) under the influence of some solvent
or gas (called moving/mobilephase).
Chromatography is anondestructiveprocedure
Applied both for both qualitative and
quantitative studies
3

Principle
Like-dissolve-like orlike-prefer-like.
The basis-partition or distribution coefficient ‘K’
which describes the way in which acompound
distributes itself between two immiscible phases.
Defined asthe molar concentration of analyte in the
stationary phase divided by the molar concentration
of the analyte in the mobilephase
𝐾 = 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 𝑜𝑓 𝑐𝑜𝑚𝑝𝑜𝑛𝑒𝑛𝑡 𝑖𝑛 𝑠𝑡𝑎𝑡𝑖𝑜𝑛𝑎𝑟𝑦 𝑝ℎ𝑎𝑠𝑒
𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 𝑜𝑓 𝑐𝑜𝑚𝑝𝑜𝑛𝑒𝑛𝑡 𝑖𝑛 𝑚𝑜𝑏𝑖𝑙𝑒 𝑝ℎ𝑎𝑠𝑒
4

CommonlyUsed
Terms
7
Analyte
Thesubstanceto be separated during
chromatography
Analytical chromatography
Determines the existence and the
concentration of analyte(s) in asample
Chromatogram
Visual output of the chromatograph

Analytical techniques

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