4: Sample Experiments
Where:
S
λ
= the sample intensity at wavelength
λ
D
λ
= the dark intensity at wavelength
λ
R
λ
= the reference intensity at wavelength
λ
The figure below shows a typical absorbance setup. The light source sends light via an input fiber into a
cuvette in a cuvette holder. The light interacts with the sample. The output fiber carries light from the
sample to the spectrometer, which is connected to the PC.
Typical Absorbance Setup
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
To take an absorbance measurement using OOIBase32, follow the steps below:
1. Place OOIBase32 in Scope mode by clicking the scope mode icon on the toolbar or selecting
Spectrum | Scope Mode
from the menu bar.
2. Ensure that the entire signal is on scale. The intensity of the reference signal should peak at about
50,000 counts. If necessary, adjust the integration time until the intensity is approximately 50,000
counts.
3. Place a sample of the solvent into a cuvette and take a reference spectrum. You must take a
reference spectrum before measuring absorbance.
220-00000-000-02-0605
19