Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual page 114

UltiMate 3000 Series:
Fluorescence Detectors FLD-3100 and FLD-3400RS
Problem
Poor peak area
precision
(Cont'd)
Page 106
Probable Cause
Carry-over occurs in the
system.
The capillary connections are
not installed properly or they
are not tight.
There are dead volumes in the
capillary connections.
The piston seals are not tight.
There is air in the working
head.
There is pump pulsation.
The gradient is irreproducible.
The sample is unstable and
decomposes.
Baseline fluctuations
The wrong emission
wavelength was selected, e.g.,
in a UV spectrum flank.
The selected response time is
too small.
The environmental conditions
are unstable.
Contamination occurs
somewhere in the system.
The detector had to
automatically adapt the
Sensitivity.
Remedial Action
Flush the needle using an appropriate
solvent (→ Autosampler Manual).
Check and tighten the capillary
connections.
Exchange the needle seat if necessary
(→ Autosampler Manual).
Exchange the needle if necessary
(→ Autosampler Manual).
Replace the fittings. Make sure that the
capillaries are installed correctly.
Thermo Fisher Scientific recommends
using Viper capillary connections
whenever possible.
Replace the seals (→ Pump Manual).
Purge the pump; check general function
(→ Pump Manual).
Use degassed solvents.
Change the gradient.
Check the pump function and degassing.
Check the filter frits in the solvent lines
for contamination and replace as
necessary.
Use new sample or change the
conditions. Cool the sample in the
autosampler.
see "Periodic baseline fluctuations,
pulsation"
Choose an emission wavelength which
is located near the apex of the spectrum.
A wavelength switch might be required.
Select a suitable response time, e.g.,
using the Chromeleon Program Wizard
(→ Fig. 31).
Make sure that the temperature and air
humidity are constant. Use column
thermostatting and/or flow cell
thermostatting. Avoid draft.
Flush the system with an appropriate
solvent.
Select an appropriate Sensitivity. Check
the Chromeleon Audit Trail to find out
whether the Sensitivity was adjusted
automatically.
Operating Instructions