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Why are ultraviolet-visible absorption peaks useful for measuring small concentrations?

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Ultraviolet-visible (UV-Vis) absorption peaks are highly effective for measuring small concentrations because the height of these peaks for many organic and inorganic compounds is significantly larger than those observed in other spectral regions. Because these absorption peaks are high, even small analyte concentrations can be detected and measured with greater ease.1

This quantitative utility is grounded in the Beer-Lambert law, which establishes that the amount of radiation absorbed is directly proportional to the concentration of the substance and the length of the path the light travels. For substances that do not naturally absorb strongly in the UV-Vis region, scientists often use spectrochemical analysis to add a reagent that forms a strongly absorbing complex, allowing for the precise measurement of very small amounts of the original analyte.231