Optimizing Your Method; Changing The Chromatographic Separation - Thermo Scientific TSQ 8000 Evo User Manual

Optimizing Your Method

Changing the Chromatographic Separation

Thermo Scientific
If you are not getting the expected results from your method, you can modify it using the
following procedures for better results.
Contents
• Changing the Chromatographic Separation
• Finding the Best Way to Make an Injection
• Improving the Way You Prepare Samples
• Changing the Dwell Time or Scan Rate
• Narrowing the Mass Range
• Adjusting the Transfer Line and Ion Source Temperature
• Optimizing an SRM Method
• Optimizing an NCI Tune
• Modifying an Automatic Tune
Peak shapes are defined by the chromatographic conditions. If your peak is too wide, too
narrow, or not symmetrical enough, then changing the chromatographic conditions are the
best way to improve your method. Start by changing the GC carrier gas flow or oven
temperatures (the initial temperature, initial hold time, ramp temperature, final temperature
for that ramp, and hold time at that final temperature). These temperatures can be adjusted
for each ramp.
Oven changes are strongly dependent on the nature of the compounds you are analyzing. At
some point, the GC oven has to be above the boiling point of the compounds you are looking
for. If the GC oven is not at the boiling point, the compounds will not volatilize and they will
become immobilized. You can change ramp rates to separate coeluting peaks. Refer to the GC
user documentation for further suggestions on optimizing chromatographic separation.
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