Optical Specifications Of Cells - Agilent Technologies Cary 8454 Installation Manual

3 Good Measurement Practices
General Considerations

Optical Specifications of Cells

The accuracy of the readings of a diode array instrument is very sensitive to
spatial shifts of the analysis light beam. Cells having non parallel opposite
faces, or so called wedge shaped cells, lead to a spatial shift of the light beam
(see Figure 5). Therefore, the opposite cell walls illuminated by the analysis
light beam have to be parallel. The degree of parallelism is measured in terms
of the angle between the two opposite cell walls. We recommend that you use
10 mm path length cells with an angle which is below 0.1 degrees of an arc.
Figure 5
34
Parallel
Cell Walls
Non-parallel
Cell Walls
Shift of the instrument light beam due to non parallel cell walls
Agilent Cary 8454 UV-Visible Spectroscopy System Installation Guide
Light Beam in
Light Beam out
Light Beam in
Light Beam out