User`s guide

Troubleshooting
372
diffuse back into the system if the filters become
overloaded.
Action: The inlet and outlet split and desorb charcoal
filters must be replaced periodically, especially
if large amounts of solvent are split from the
sample. Contact your PerkinElmer service
engineer.
Cause: Contamination is coming from the cold trap.
Action: If the contamination appears to be coming from
the cold trap itself, i.e., the contamination level
does not increase with exposure time to the gas
flow, the trap should either be conditioned or
repacked with fresh adsorbent. See Cold Trap
Maintenance on page 277 for details on
conditioning and repacking the trap.
Cause: If you are using an on-column connection, the
injection volume may be too high and the GC
column is being overloaded.
Action: Increase the inlet or outlet split ratios, to reduce
the sample that reaches the GC.
Action: Increase the flow of carrier gas through the
transfer line, and then set the transfer line
temperature to 210°C. Allow the transfer line to
purge overnight.
Cause: If you are using an on-column connection, the
transfer line temperature may be too high for the
column liquid phase.
Action: Ensure that the column liquid phase can
withstand the transfer line temperature. If not,
then set the transfer line temperature to the
maximum allowable for the selected column
liquid phase.
Minimize contamination of the carrier gas flow path within the
ATD/TD at all times by ensuring that the line and valve
temperatures are sufficiently high for the sample type and the
desorption conditions used.
Ensure that no adsorbent or sample material migrates from the tube