Biotage ELSD-1080, Operation Manual

Page: 51 / 59

Biotage ELSD-1080
5.3 General Problems
Faults or
Problems Possible Cause(s) Remedy
Baseline noise Poor nebulization of solvent
Insufficient evaporation
Non-volatile additive in
mobile phase
Pressure difference created
inside nebulizer chamber
Pump pulsations, especially
in microbore applications
where low flow rates are
used
Increase the temperature of
the evaporator by 10°
intervals until the noise is
acceptable
Increase the evap gas flow
rate
Decrease the nebulization
temperature
Ensure that the end of the
liquid waste tube is not
immersed in liquid
Ensure that the exhaust tube
at rear of unit is not blocked,
or extraction is too strong
Use a pulse free pump
Increase the back pressure
on the pump by fitting a
back pressure column
between the pump and the
injection valve
Use a pulse dampener
directly after the pump in
the system
Use a volatile mobile phase
as shown
Baseline spikes Particulate matter in the gas
supply
Column shedding
Poor nebulization
Non-volatile additive in
mobile phase
Filter the incoming gas, or
change the supply
Replace column or fit an
inline filter with a 0.2 µm
membrane filter directly
after the column
Replace additive in mobile
phase with volatile buffer
Low sensitivity
and baseline
noise/drift Diffuser saturated with
solvent Stop the eluent flow and
increase the evaporator
temperature to
maximum. Increase the flow
rate to 2.8 SLM and wait 1
hour
Publication date: July 2010 51