Ocean Optics OOIBase32 - Manual (Page 99)

A: Experiment Tutorials
Absorbance Experiments
Absorbance spectra are a measure of how much light a sample absorbs. For most samples, absorbance
relates linearly to the concentration of the substance. OOIBase32 calculates absorbance (A
λ ) using the
following equation.
S λ - D λ
A λ = -
log
10
(
R λ -
D λ
)
Where:
S
λ = Sample intensity at wavelength
λ
D
λ = Dark intensity at wavelength
λ
R
λ = Reference intensity at wavelength
λ
Typical absorbance setup: The light source (far right) sends light via an input fiber into a cuvette in a
cuvette holder (bottom center). The light interacts with the sample. The output fiber carries light from the
sample to the spectrometer (top center) connected to the PC (far left).
Absorbance is also proportional to the concentration of the substance interacting with the light (this is
known as Beer’s Law). Common absorption applications include the quantification of chemical
concentrations in aqueous or gaseous samples.
► Procedure
Follow the steps below to take an absorbance measurement using OOIBase32:
1. Place OOIBase32 in scope mode by clicking the scope mode icon on the toolbar or selecting
Spectrum | Scope Mode from the menu bar.
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