Agilent Technologies 8453 Operator's Manual page 194

Table 45
Diagnostics and Troubleshooting
General Troubleshooting Hints
Excessive Spikes or Glitches on Spectra
Causes and solutions for excessive spikes or glitches on spectra are shown in
Table 45.
Excessive Spikes or Glitches on Spectra
Possible Causes
BLANK on air, SAMPLE on cuvette.
Dramatic changes in the refractive index from
BLANK to SAMPLE.
Wedge shaped cuvettes (low quality
cuvettes, mostly (not always) plastic
cuvettes; there are non-wedge shaped plastic
cuvettes available).
Bubbles in the cell (even very small ones are
sufficient to create spikes).
Floating particles in the cell (from cleaning
tissues, or the application, or other kind of
dirt).
Any kind of addionally mounted optical
devices put into the light path of the
instrument.
Turbid samples (especially in kinetics when a
mixing process occurs during measurement).
88
Action
Measure Blank on the same solvent as used
for the sample.
Measure Blank on the same solvent as used
for the sample.
Use high quality quartz cuvettes.
Try to get rid of the bubbles by gently
knocking the cell on a desk. Rinsing the cells
with a cleaning and pasivating solution
makes the bubbles less sticky to the
windows.
Sometimes the use of degassed solvent
prevents the building of bubbles and make to
time between filling the cells and the
measurement as short as possible.
Cells have to be cleaned using cleaning and
pasivating solution. Use optical tissues to
wipe the outer surface of the cells.
The manipulation of the optical
characteristics can cause some decrease in
optical performance. No corrective action
execpt the remove of the optical active device
can change the behavior.
Avoid turbidity, e.g. by filtration.