A spectrophotometer is an instrument that measures the intensity of light passing through a sample based on Beer's Law and Lambert's Law. It works by using a light source, monochromator, and detector to measure how much light is absorbed by a sample in a cuvette. The amount of light absorbed can then determine the presence, concentration, and purity of chemicals in samples and measure changes over time.

1. BASICS OF
SPECTROPHOTOMETER
Dr. J. Merrylin
Assistant Professor
Dept. of Food Science & Nutrition
Sarah Tucker College

3. SPECTROPHOTOMETER
• An instrument which measures the light intensity passing through the sample

4. Principle
• Beer’s Law – concentration of a chemical is directly proportional to
the absorbance of a solution

5. Contd….
• Lambert’s Law - When a beam of light is allowed to pass through a
transparent medium, the rate of decrease of intensity with the thickness of
medium is directly proportional to the intensity of light

6. Parts - Internal
• Light Source
• Monochromator
• Cuvette
• Detectors

7. Light Source
• Tungsten
• Helium
• Deutrium
• UV

8. Monochromator

9. Detectors
• Photocell
• Phototube
Detector

10. External Parts

11. Working

12. Application
• Determines the presence and concentration of samples
• Determines the purity of a sample
• Measures the change of sample over time

13. Thank You