This preview shows page 1. Sign up to view the full content.
Unformatted text preview: d the operation of the GENESYSTM 20 before you begin
this laboratory. The GENESYSTM 20 is an expensive and sensitive instrument and must
be operated carefully and intelligently.
The light source in a GENESYSTM 20 is an ordinary tungsten lamp whose radiation
extends over the entire visible range. The light from the lamp passes through an entrance
slit and is dispersed by a diffraction grating. The grating can be rotated so that a small
band of selected wavelengths from the dispersed beam passes through an exit slit, and
then through the cell (cuvette) containing the sample. The cuvettes used with a
GENESYSTM 20 have a path length (internal diameter) of 1.00 cm. The light transmitted
through the sample strikes a solid-state silicon detector that generates an electrical signal
proportional to the radiant power (light intensity). The signal from the detector drives a
meter that can be calibrated to read transmittance or absorbance.
The calibration procedure entails setting 0 Absorbance at a given wavelength with a
cuvette containing a reference or...
View Full Document
- Spring '07