The key difference between filter photometer and spectrophotometer is that filter parameter uses a single or limited number of parameters determined by fixed wavelengths, whereas spectrophotometer uses numerous parameters determined by the wavelength range.
A filter photometer is a colorimeter in which the length of the light is selected by the use of appropriate glass filters. A spectrophotometer is an analytical instrument that can measure the concentration of a sample by measuring light absorption.
CONTENTS
1. Overview and Key Difference
2. What is Filter Photometer
3. What is Spectrophotometer
4. Filter Photometer vs Spectrophotometer in Tabular Form
5. Summary – Filter Photometer vs Spectrophotometer
What is Filter Photometer?
A filter photometer is a colorimeter in which the length of the light is selected by the use of appropriate glass filters. This type of photometer uses optical filters to give monochromatic light. In other words, these photometers allow monochromatic light to pass through a container known as a cell with optically flat windows that consists of the solution.
Then the light reaches a light detector that can measure the intensity of the light in comparison to the intensity after the light pass through an identical cell having the same solvent but without the colored substance. Thereafter, we can use the ratio between the light intensities and the capacity of the colored substance to absorb light for the calculation of the concentration of the substance using Beer’s law.
What is Spectrophotometer?
A spectrophotometer is an analytical instrument that can measure the concentration of a sample by measuring light absorption. It uses the reflection or transmission properties of a material as a function of wavelength. This instrument can operate in visible light, near UV, and near IR lights, as well. We use a cuvette to place the sample inside the instrument. Then a light beam passes through the sample and diffracts into a spectrum of wavelengths. Then the instrument measures the intensities via a charge-coupled device. Finally, we get the results of the analysis on the display device after passing the detector.
We can use this instrument to detect organic compounds as well. That is by determining the absorption maxima. Moreover, we can use it to determine the colour within a spectral range. Most importantly, we use it to measure the concentration of a component in a sample by determining the amount of light absorbed by that component.
What is the Difference Between Filter Photometer and Spectrophotometer?
A filter photometer is a colorimeter in which the length of the light is selected by the use of appropriate glass filters. A spectrophotometer is an analytical instrument that can measure the concentration of a sample by measuring light absorption. The key difference between filter photometer and spectrophotometer is that filter parameter uses a single or limited number of parameters determined by fixed wavelengths, whereas spectrophotometer uses numerous parameters determined by the wavelength range. In addition, filter photometer has stationary parts, is light weight, and good for field use, while spectrophotometer has moving parts, is heavier, and good for bench use.
The below infographic presents the differences between filter photometer and spectrophotometer in tabular form for side by side comparison.
Summary – Filter Photometer vs Spectrophotometer
Photometers are important analytical instruments. The key difference between filter photometer and spectrophotometer is that filter parameter uses a single or limited number of parameters determined by fixed wavelengths, whereas spectrophotometer uses numerous parameters determined by the wavelength range.
Reference:
1. Ken, Phillips. “What Is a Spectrophotometer and How Does It Work?” HunterLab Horizons Blog, 22 Sept. 2020.
Image Courtesy:
1. “Spectrophotometer for nutrients analysis (in urine)” By SuSanA Secretariat (CC BY 2.0) via Flickr
2. “Spectrophotometer Model 2” By Viv Rolfe – Own work (CC BY-SA 4.0) via Commons Wikimedia