Varian 4000 GCMS, Installation Procedures Manual

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Section 5. Achieving Internal EI
Specifications
NOTE: If the MS is configured in external mode please proceed to Section 7 of
this document.
The EI specifications for a 4000 GCMS system in Internal mode:
20:1 RMS signal-to-noise using the m/z 272 ion from a 1 µL injection of a 2 pg/µL
OFN solution (03-931126-01). A 10:1 split ratio can be used to reduce the
amount of OFN from 2 pg to 200 fg. If necessary, a 10:1 dilution can be done
using customer supplied glassware and 2,2,4-trimethylpentane (isooctane) to
reduce the amount of OFN from 2 pg to 200fg. In addition, a background
corrected spectrum should be library searchable with any match > 500. If a Quick
Switch Valve is used in the GC oven the signal-to-noise spec is reduced from
20:1 to 10:1.
5.1 Methodology
NOTE: The 4000 GCMS system will arrive with a Test Files CD containing
factory test method and data files. These method files can be used to pass the
sensitivity tests associated with the installation. At the factory a diluted OFN
standard is injected using a pressure pulse and splitless injection technique. If a
diluted OFN standard is to be used at an installation the method from the Test
Files CD can be used with no editing. If a split style injection is to be used at an
installation, the Test Files CD method should be edited to remove the pressure
pulse and introduce a 10:1 split ratio. Retain the Test Files CD for your records.
Ensure the MS temperatures are set for this acquisition:
•
Trap: 150 °C
•
Manifold: 40 °C
•
Transfer Line: 230 °C
If necessary, edit the Test Files CD internal EI method and activate the method
in System Control.
Figure 5.1 shows System Control in a Ready state. Both the GC window and the
MS window must be Ready for System Control to be Ready.