Troubleshooting
104
6
Unusually high LC back-
pressure
Continued
APCI probe filter pad is
blocked.
Replace the filter pad. See
Tubing from LC system is
blocked.
Remove the finger-tightened
nut and tubing from the back
of the probe. If the back pres-
sure remains relatively high,
replace the tubing.
The ESI stainless steel
sample capillary inside the
probe is blocked.
Try reversing the capillary to
clear any blockage. If this
fails to correct the problem,
replace the capillary.
The ESI capillary is not fully
seated in the LC union or
the APCI capillary is not
properly seated in the filter.
Remove and disassemble
the probe, and reseat the
capillary correctly in union.
Unusually low LC back-
pressure
Leaking connector.
Check all fittings and tighten
where necessary.
Problem with LC solvent
delivery.
Troubleshoot the LC system.
Broken flow cell in UV
detector.
Replace the flow cell.
Insufficient vacuum – (any
reading higher than 1
×
10
–4
mbar on the Pirani
gauge)
Leaking ion block O-rings.
Disassemble the source, and
examine the ion block
O-rings. See
Roughing pump not oper-
ating correctly.
Examine the vacuum pump
oil. If it is dirty, flush the
pump with clean oil. Then
refill it with fresh oil. Repeat
the procedure, if necessary.
Leak in vacuum backing
line.
Examine the vacuum hose
for cracks or vacuum leaks.
Restriction in vacuum pump
exhaust tubing.
Examine the exhaust line for
restrictions.
The turbomolecular pump
does not operate properly.
Check for operating defects.
Table 6-1 Hardware Troubleshooting (Continued)
Symptom
Possible Cause
Corrective Action
Summary of Contents for Micromass ZQ 2000
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