Technological Method in Forensic Science
BSC-FS-302
Unit 1: Instrumentation
Basics of Instrumentation
Introduction to Instrumentation: Instrumentation refers to the science and technology of measurement and
control of physical, chemical, and biological variables using instruments. It involves the design, construction,
and application of measuring tools to obtain accurate and reproducible data.
Key Components of an Instrument:
Component Function
Sensor/Detector Detects the physical or chemical property (e.g., light, temperature, pressure).
Transducer Converts one form of energy into another (e.g., heat to voltage).
Signal Conditioner Amplifies, filters, or modifies the signal from the sensor.
Display/Output Unit Shows the final readable result (analog/digital).
Data Processor Stores, analyzes, and processes the data (optional, in modern instruments).
Types of Measurements in Instrumentation
• Physical – temperature, pressure, volume, flow, etc.
• Chemical – concentration, pH, conductivity, etc.
• Biological – enzyme activity, DNA/RNA quantification, etc.
Classification of Instruments
Type Examples
Analytical Instruments UV-Vis Spectrophotometer, Chromatograph, AAS, FTIR
Measuring Instruments Thermometer, Manometer, Multimeter
Control Instruments pH meter (with control), temperature controllers
Important Instrumental Techniques
,Technique Principle Application
Spectrophotometry Absorption of light by substances Concentration analysis
Drug, toxin, DNA
Chromatography Separation based on differential partitioning
profiling
Movement of charged molecules in an
Electrophoresis DNA/RNA separation
electric field
Ionization and detection of mass-to-charge
Mass Spectrometry (MS) Molecular identification
ratio
Atomic Absorption Spectroscopy
Absorption of radiation by atoms Metal analysis
(AAS)
Microscopy Magnification of small objects Cellular/tissue study
Chromatography
Introduction to Chromatography: Chromatography is an important biophysical technique that enables the
separation, identification, and purification of the components of a mixture for qualitative and quantitative
analysis.
Chromatography is a physical separation technique used to separate, identify, and quantify components in a
mixture based on their differential distribution between two phases:
• Stationary phase (fixed)
• Mobile phase (moving)
Basic Principle: The principle of chromatography is based on differential partitioning or adsorption of
components between the stationary phase and the mobile phase.
Each component in a mixture moves at a different speed due to differences in:
• Solubility
• Molecular size
• Polarity
• Affinity for the stationary phase
Result: The components separate as they migrate through the stationary phase with the mobile phase.
Major Types of Chromatographic Techniques
,Type Stationary Phase Mobile Phase Example
Paper Chromatography Filter paper Solvent (liquid) Pigment separation
Thin Layer Chromatography (TLC) Silica gel on a plate Solvent (liquid) Drug analysis
Liquid/solid in a Inert gas (e.g., Volatile compound
Gas Chromatography (GC)
column helium) separation
Liquid Chromatography (LC) Silica or polymer Liquid solvent Pharmaceutical testing
High-Performance Liquid Drug/metabolite
High-pressure column Liquid solvent
Chromatography (HPLC) quantification
Silica or alumina in a Natural product
Column Chromatography Liquid solvent
column purification
Key Concepts:
a. Retention Time (tR): Time taken by a compound to pass through the column from the point of injection to
detection.
b. Retention Factor (Rf): (used in TLC/Paper Chromatography)
c. Partition Coefficient (K):
This influences how strongly a component is retained.
Modes of Chromatographic Separation:
Mode Principle
Adsorption chromatography Separation based on adsorption on solid surfaces (e.g., TLC, Column)
Separation based on solubility in two liquid phases (e.g., Paper
Partition chromatography
Chromatography)
, Mode Principle
Ion exchange
Based on charge of molecules (e.g., protein purification)
chromatography
Size exclusion
Based on molecular size (large molecules elute first)
chromatography
Affinity chromatography Based on specific binding (e.g., antibody-antigen)
Thin Layer Chromatography
Definition: Thin Layer Chromatography can be defined as a method of separation or identification of a mixture
of components into individual components by using finely divided adsorbent solid / (liquid) spread over a plate
and liquid as a mobile phase.
Principle of Thin Layer Chromatography (TLC)
• Thin-layer chromatography is performed on a sheet of glass, plastic, or aluminium foil, which is coated
with a thin layer of adsorbent material, usually silica gel, aluminium oxide (alumina), or cellulose. This
layer of adsorbent is known as the stationary phase.
• After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase)
is drawn up the plate via capillary action. Because different analytes ascend the TLC plate at different
rates, separation is achieved.
• It is thus based on the principle of adsorption chromatography or partition chromatography or
combination of both, depending on adsorbent, its treatment and nature of solvents employed. The
components with more affinity towards stationary phase travel slower. Components with less affinity
towards stationary phase travels faster.
BSC-FS-302
Unit 1: Instrumentation
Basics of Instrumentation
Introduction to Instrumentation: Instrumentation refers to the science and technology of measurement and
control of physical, chemical, and biological variables using instruments. It involves the design, construction,
and application of measuring tools to obtain accurate and reproducible data.
Key Components of an Instrument:
Component Function
Sensor/Detector Detects the physical or chemical property (e.g., light, temperature, pressure).
Transducer Converts one form of energy into another (e.g., heat to voltage).
Signal Conditioner Amplifies, filters, or modifies the signal from the sensor.
Display/Output Unit Shows the final readable result (analog/digital).
Data Processor Stores, analyzes, and processes the data (optional, in modern instruments).
Types of Measurements in Instrumentation
• Physical – temperature, pressure, volume, flow, etc.
• Chemical – concentration, pH, conductivity, etc.
• Biological – enzyme activity, DNA/RNA quantification, etc.
Classification of Instruments
Type Examples
Analytical Instruments UV-Vis Spectrophotometer, Chromatograph, AAS, FTIR
Measuring Instruments Thermometer, Manometer, Multimeter
Control Instruments pH meter (with control), temperature controllers
Important Instrumental Techniques
,Technique Principle Application
Spectrophotometry Absorption of light by substances Concentration analysis
Drug, toxin, DNA
Chromatography Separation based on differential partitioning
profiling
Movement of charged molecules in an
Electrophoresis DNA/RNA separation
electric field
Ionization and detection of mass-to-charge
Mass Spectrometry (MS) Molecular identification
ratio
Atomic Absorption Spectroscopy
Absorption of radiation by atoms Metal analysis
(AAS)
Microscopy Magnification of small objects Cellular/tissue study
Chromatography
Introduction to Chromatography: Chromatography is an important biophysical technique that enables the
separation, identification, and purification of the components of a mixture for qualitative and quantitative
analysis.
Chromatography is a physical separation technique used to separate, identify, and quantify components in a
mixture based on their differential distribution between two phases:
• Stationary phase (fixed)
• Mobile phase (moving)
Basic Principle: The principle of chromatography is based on differential partitioning or adsorption of
components between the stationary phase and the mobile phase.
Each component in a mixture moves at a different speed due to differences in:
• Solubility
• Molecular size
• Polarity
• Affinity for the stationary phase
Result: The components separate as they migrate through the stationary phase with the mobile phase.
Major Types of Chromatographic Techniques
,Type Stationary Phase Mobile Phase Example
Paper Chromatography Filter paper Solvent (liquid) Pigment separation
Thin Layer Chromatography (TLC) Silica gel on a plate Solvent (liquid) Drug analysis
Liquid/solid in a Inert gas (e.g., Volatile compound
Gas Chromatography (GC)
column helium) separation
Liquid Chromatography (LC) Silica or polymer Liquid solvent Pharmaceutical testing
High-Performance Liquid Drug/metabolite
High-pressure column Liquid solvent
Chromatography (HPLC) quantification
Silica or alumina in a Natural product
Column Chromatography Liquid solvent
column purification
Key Concepts:
a. Retention Time (tR): Time taken by a compound to pass through the column from the point of injection to
detection.
b. Retention Factor (Rf): (used in TLC/Paper Chromatography)
c. Partition Coefficient (K):
This influences how strongly a component is retained.
Modes of Chromatographic Separation:
Mode Principle
Adsorption chromatography Separation based on adsorption on solid surfaces (e.g., TLC, Column)
Separation based on solubility in two liquid phases (e.g., Paper
Partition chromatography
Chromatography)
, Mode Principle
Ion exchange
Based on charge of molecules (e.g., protein purification)
chromatography
Size exclusion
Based on molecular size (large molecules elute first)
chromatography
Affinity chromatography Based on specific binding (e.g., antibody-antigen)
Thin Layer Chromatography
Definition: Thin Layer Chromatography can be defined as a method of separation or identification of a mixture
of components into individual components by using finely divided adsorbent solid / (liquid) spread over a plate
and liquid as a mobile phase.
Principle of Thin Layer Chromatography (TLC)
• Thin-layer chromatography is performed on a sheet of glass, plastic, or aluminium foil, which is coated
with a thin layer of adsorbent material, usually silica gel, aluminium oxide (alumina), or cellulose. This
layer of adsorbent is known as the stationary phase.
• After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase)
is drawn up the plate via capillary action. Because different analytes ascend the TLC plate at different
rates, separation is achieved.
• It is thus based on the principle of adsorption chromatography or partition chromatography or
combination of both, depending on adsorbent, its treatment and nature of solvents employed. The
components with more affinity towards stationary phase travel slower. Components with less affinity
towards stationary phase travels faster.
