L1 /
8
CH3041
UV-VIS SPECTROSCOPY
UltraViolet-Visible Spectroscopy (UV-Vis)
• In a double-beam
spectrophotometer the
sample is placed in a plastic (Vis) or quartz (UV) cuvette of 1cm path length (l).
sample is placed in a plastic (Vis) or quartz (UV) cuvette of 1cm path length (l).
• 1) run the solvent in
both cuvettes
• 2) calibrate with
calibration samples
• 3) the test samples are run.
• eg. PTotal IDL 0.1 ppm.
“Moly-Blue” method
Monochromator
Detector
Light
Source
Source
(W lamp
visible)
visible)
Semi-transparent mirror
Rotating mirror
beam-chopper
beam-chopper
Visible absorption signal
Reference
Sample
mirror
mirror
(1 wavelength)
(photomultiplier
or
diode array)
