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How does an absorption spectrometer measure the amount of light absorbed by a sample?

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An absorption spectrometer measures the amount of light absorbed by a sample by comparing the intensity of incident radiation before and after it passes through the material.1

The process relies on three essential components:
* Radiation Source: Provides electromagnetic radiation in the specific energy region required for the analysis.1
* Sample Cell: A transparent container that holds the analyte, allowing the radiation to pass through a fixed path length.1
* Detector: Measures the intensity of the radiation after it has traversed the sample.1

As radiation passes through the sample, molecules absorb photons, causing the intensity of the beam to decrease. Because the amount of absorption is proportional to the concentration of the analyte and the path length of the cell, this relationship is governed by the Beer-Lambert law. By using a monochromator or filters to control the wavelength, the instrument can isolate specific energy bands to perform precise quantitative or qualitative analysis.12