Agilent Technologies 5975T LTM GC/MSD, Руководство по устранению неисправностей и техническому обслуживанию

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42 Troubleshooting and Maintenance Guide
3
Chromatographic Symptoms
Baseline Rise During LTM Column Temperature Program
• Inspect the column for bleed.
• Check for leaks/oxygen in carrier gas supply.
• Check gas supply oxygen trap indicator or date.
•
Make solvent blank runs to evaluate baseline without
sample.
• Make “no injection” blank runs (remove the syringe from the
injector and start a run) to evaluate baseline without
solvent.
• Check for contamination. (See “Contamination or
Carryover” on page 37.)
• Consider the effect of column film thickness on bleed.
• Check for leaks at the column fittings. (See “Checking for
Leaks” on page 99.)
• Prepare and use a column compensation profile.
Baseline is rising
• Column bleed
• Other contamination
Baseline is high
• Column bleed
• Other contamination
• Electron multiplier voltage is too high
Baseline is falling
A falling baseline indicates contamination is being swept away. Wait
until the baseline reaches an acceptable level. Common causes
include:
• Residual water air and water from a recent venting
• Column bleed
• Septum bleed