Lab 1 Spectrophotometry (Practical) PDF
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This document is a practical guide to spectrophotometry that outlines types of spectrophotometers, their parts (light sources, monochromators, beam splitters, sample holders, detectors), and measurements. It's an educational resource for students learning about light and color measurement for lab experiments or research.
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Colorimetry and Spectrophotometry (practical) Lab 1 Types of Spectrophotometer 1. Single beam spectrophotometer: It operates between 325 nm to 1000 nm wavelength using the single beam of light The light tra...
Colorimetry and Spectrophotometry (practical) Lab 1 Types of Spectrophotometer 1. Single beam spectrophotometer: It operates between 325 nm to 1000 nm wavelength using the single beam of light The light travels in one direction and the test solution and blank are read separtely 2. Double beam spectrophotometer: It operates between 185 nm to 1000 nm wavelength. It has two photocells This instrument splits the light from the Monochromator into two beams One beam is used for reference and the other for sample reading. Parts of Spectrophotometer Parts of Spectrophotometer 1. Light source – To generate light Tungsten Halogen lamp for visible light (400- 800 nm) Hydrogen or deuterium lamp for Ultraviolet light (200-400 nm) Xenon flash lamp for both visible and UV radiations (190-1000 nm) 2. Monochromator – To select the particular wavelength Accept polychromatic input light and outputs monochromatic light Entrance slit Exit slit Dispersion device Prizm Absorption filter (Glass) Interference filter (Metal or thin film) Monochromator 3. Beam splitters A beam splitter is an optical device that splits a beam in two directions The radiation coming from the monochromator is split into two beams and passed simultaneously through the reference and the sample cell 4. Sample holder and Sample Cell – Test tube or Cuvettes are used to hold the colored solutions They are made up of plastic, glass or optical grade quartz 5. Photodetector system – When light falls on the detector system, an electric current is generated that reflects the galvanometer reading 6. Measuring device – The current from the detector is fed to the measuring device – the galvanometer The meter reading is directly proportional to the intensity of light Galvanometer Spectrophotometer Galvanometer
