
320
Nitrogen Phosphorus Detector (NPD)
Recommended settings
4 of 32
Jun 2001
Agilent 6890 Gas Chromatograph Service Manual
Recommended settings
Equilibration time
We recommend an equilibration time of 0.0 minutes and the automatic
Adjust offset
process. Some beads do not respond well to the automatic
process. For these, start at 2.0 volts and bring up the bead voltage gradually,
10 mV at a time, until the desired offset is reached.
Turning hydrogen off during a solvent peak
The baseline shifts after a solvent peak and can take some time to stabilize,
especially with chlorinated solvents. To minimize this, turn off the hydrogen
flow during the solvent peak and turn it back on after the solvent elutes. With
this technique, the baseline recovers to its original value in less than 30
seconds. This also extends the life of the bead. The hydrogen can be turned
on and off automatically as part of a Run Table.
Turning hydrogen off between runs
To extend bead life, turn off the hydrogen flow between runs. Leave all other
flows and the detector temperature on. Turn on the hydrogen flow for the
next run; the bead will ignite almost immediately. The process can be
automated with Run Table entries.
Bead voltage
Typical voltages for new beads range from 2.5 to 3.7 volts. Higher values
reduce bead life.
Extending the life of the bead
•
Use the lowest practical adjust offset or bead voltage.
•
Run clean samples.
•
Turn the bead off when not in use.
•
Keep the detector temperature high (320 to 335°C).
Содержание 6890 Series
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Страница 27: ...24 of 24 Jun 2001 Contents Contents Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 195: ...260 Solvent Vapor Exit Accessory Leak testing 10 of 10 Jun 2001 Inlets Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 389: ...360 Auxiliary EPC Replacement procedures 16 of 16 Jun 2001 Detectors Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 479: ...520 Gases Supplying valve actuator air 14 of 14 Jun 2001 Site Preparation Agilent 6890 Gas Chromatograph Service Manual ...
Страница 485: ...530 Power Grounding 6 of 6 Jun 2001 Site Preparation Agilent 6890 Gas Chromatograph Service Manual ...
Страница 491: ...540 Instrument Specifications Detectors 6 of 6 Jun 2001 Site Preparation Agilent 6890 Gas Chromatograph Service Manual ...
Страница 492: ...600 Performance Verification How to check the performance of the 6890 instrument 610 Checkout Chromatograms ...
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Страница 555: ...840 Shutdowns 10 of 10 Jun 2001 Error Codes and Internal Diagnostics Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 637: ...1110 Valves Liquid sample valves 6 of 6 Jun 2001 Valves Agilent 6890 Gas Chromatograph Service Manual ...
Страница 647: ...1120 Valve Box Removing the valve box assembly 10 of 10 Jun 2001 Valves Agilent 6890 Gas Chromatograph Service Manual ...
Страница 675: ...1150 Troubleshooting Pressure check 6 of 6 Jun 2001 Valves Agilent 6890 Gas Chromatograph Service Manual ...
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Страница 717: ...1225 Main Board 6890N Fuses 6 of 6 Jun 2001 Electrical Agilent 6890 Gas Chromatograph Service Manual ...
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