Agilent Technologies 1290 Infinity User Manual page 113

When The interval to replace the Needle Seal depends on the number of penetrations. Two factors may be
considered for the decision to replace the Needle seal:
• Leak, seal not reliable
• Carry-over
Parts required #
1
LC Injector HTC/HTS Firmware (level 2.4.X or higher) provides a counter for the number of
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injections performed with the LC Injector HTC/HTS System. This counter monitors the
valve switches and not the number of penetrations into the injection port, e.g. for cleaning
the valve an extra penetration is required. It is advisable to monitor this counter in
conjunction with the test for the tightness of the Needle Seal as described above.
• After running routinely a few weeks, the warning limit for the Inject Counter gradually
• Path: Menu > Info > Maintenance > Inject Limit (Inject Counts reflects the actual
To ensure reproducible sample injection and minimize carry-over it is critical that:
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• The valve needle guide and the valve needle seal be installed properly,
• The valve needle seal be changed on a regular interval, details see below,
• The needle penetration depth be set accurately.
Agilent 1290 Infinity LC Injectors HTC/HTS User Manual
Remove the Needle Seal from the inlet port and insert a syringe manually with the corresponding
needle gauge (standard Gauge 22 OD 0.72 mm). Move the needle below the seal point of the
ferrule. If no resistance is observed at this point, replace the Needle seal.
In case of any doubt of possible contamination of the Needle Seal with a compound, replace the
Needle Seal. Contamination can occur if the sample solution is accidentally dispensed too fast
into the valve system. The restriction of valve and loop may cause backpressure and the sample
solution can be forced backwards into the inlet port of the valve.
p/n Description
5188-6478 Needle Seals, Rheodyne Valve (10/pk) FEP tubing with SST ferrule, Needle
Gauge 22 (OD 0.72 mm)
becomes more evident and will be a valuable tool for the user in routine work.
number of injections).
LC Injector HTC/HTS Description and Installation
3
Injection Valve
113