INTRODUCTION TO SPECTROSCOPIC METHOD OF

ANALYSIS

BASIC INSTRUMENTAL ANALYSIS

Simon J. GarretUiTM chemical engineering

Simon J. GarretUiTM chemical engineering

1.1 Properties of Electromagnetic Spectrum

• Electromagnetic Spectrum/Radiation– A form of energy that is transmitted through

space at enormous velocity

• It could be described as a wave with properties of wavelength, frequency, velocity and amplitude

Wave propertiesElectromagnetic radiation is modeled as waves

consisting of perpendicularly oscillating electric & magnetic fields

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1.1 Properties of Electromagnetic Spectrum

Wave characteristics• Amplitude – length of electric field at the wave maximum• Wavelength λ – linear distance between successive

maxima/minima• Period p – time in seconds required for the passage of

successive maxima/minima through a fixed point in a space• – number of oscillations of the electric field

vector per unit time• – wave front through as a medium depends

on both medium and frequency

1.1 Properties of Electromagnetic Spectrum

1.1 Properties of Electromagnetic Spectrum

Speed of lightVelocity of light c = 3 x 108 ms-1

– number of waves per cm

Particulate Nature of light: PhotonEnergy of a photon:

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1.3 Atomic and Molecular Energy

1.4 Components of Instruments for Optical Radiation

• Most optical instruments are made of five components:1. A stable source of radiant energy2. A wavelength selector that isolates a limited region

of the spectrum for measurement3. One or more sample containers4. A radiation detector which converts radiant energy

to a measurable electrical signal5. A signal processing and readout unit - computer

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