Polymer Laboratories PL-ELS 2100, Service Manual, Page: 17 / 80

Version 2.0
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General Proble ms
Fault/Proble ms Possible Cause(s) Remedy
Baseline noise The particle plume is not sufficiently
dried in the evaporator tube.

Increase the temperature of the
evaporator by 10ƒ intervals until the
noise is acceptable
Baseline noise Poor nebulisation of solvent

Increase the gas flow rate

Decrease the nebulisation
temperature
Baseline noise Pump pulsations, especially in
microbore applications where low flow
rates are used.

Use a pulse free pump

Increase the back pressure on
the pump by fitting a back pressure
regulator between the pump and the
injection valve.

Use a pulse dampener directly
after the pump in the system.
Baseline spikes 1. Particulate matter in the gas supply
2. Column shedding
3. Poor nebulisation

Filter the incoming gas, or
change the supply

Replace column or fit an inline
filter with a 0.2…m membrane filter
directly after the column.

Nebuliser temperature may be
too high and solvent may be boiling;
reduce nebuliser temperature
Low sensitivity and
baseline noise Diffuser saturated with solvent

Stop the eluent flow and
increase the evaporator temperature
to 50ƒC above the current set
temperature. Increase the flow rate
to 2.8SLM and wait 15mins.
Large Baseline offset 1. Inefficient evaporation
2. High concentration of non-volatile
buffer or stabiliser
3. Contaminated diffuser

Increase the evaporator
temperature and/or gas flow.

Use a lower concentration of
stabiliser, unstabilised solvent or a
more volatile buffer

Perform ‘steam clean’.
(Section 4.2 Operation’s manual)
Peak tailing Eluent particles lingering in the optical
chamber

Increase gas flow rate
Instrument Fails to zero Offset too high or output unstable

Ensure the instrument is in
RUN mode

Refer to local distributor or
Polymer Laboratories
No power 1. Mains lead not connected
2. Fuse failure

Attach mains lead to socket and
inlet on rear of instrument

Replace fuse
No response
(completely flat
baseline) 1. Data acquisition leads not
connected
2. Light source inactive
3. Instrument in STANDBY mode

Ensure connectors to computer
or integrator are sound

Check LED

Select RUN mode
Temperature error as
soon as instrument
powered on Temperature probe fault or
disconnected

Check RTD connections
Display not on, but
power connected, blue
glow ON. Instrument in service mode

Rear panel switch-set to RUN