13: Introduction to Ultraviolet/Visible Absorption Spectrometry
- Page ID
- 333366
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- 13.1: Transmittance and Absorbance
- As light passes through a sample, its power decreases as some of it is absorbed. This attenuation of radiation is described quantitatively by two separate, but related terms: transmittance and absorbance.
- 13.2: Beer's Law
- Beer's law connects absorbance to the concentration of the absorbing species. In this section we derive Beer's law and consider some of its limitations.
- 13.3: Effect of Noise on Transmittance and Absorbance Measurements
- In absorption spectroscopy, precision is limited by indeterminate errors—primarily instrumental noise—which are introduced when we measure absorbance. Precision generally is worse for low absorbances and for high absorbances . We might expect, therefore, that precision will vary with transmittance.
- 13.4: Instrumentation
- As covered in Chapter 7, the basic instrumentation for absorbance measurements consists of a source of radiation, a means for selecting the wavelengths to use, a means for detecting the amount of light absorbed by the sample, and a means for processing and displaying the data. In this section we consider two other essential components of an instrument for measuring the absorbance of UV/Vis radiation by molecules: the optical path that connects the source to the detector and a means for placing t