This note provides a method for improving GC performance in order to perform trace level GC/MS analysis. The note summarizes suggestions for improving GC performance, including using high purity carrier gas, optimizing sample injection and using optimized GC columns.
The document serves as a "how-to" guide for improving the performance of an Agilent 6890 Series GC used with a 5973 MSD. It focuses on optimizing the gas plumbing, inlet system, and column connections to enhance sensitivity and reduce chemical noise.
Key recommendations include using high-purity helium (≥99.999%), installing mass spectrometer gas purifier traps vertically or diagonally, and utilizing specific consumables like single tapered deactivated liners and Merlin Microseal™ septum systems. The text also details the proper installation of column nuts and ferrules to ensure leak-tight seals.
| Carrier gas purity requirement | at least 99.999% helium |
|---|---|
| Recommended column dimensions for trace analysis | 30 m, 0.25 mm ID, 0.25 µm film |
| Recommended septum replacement frequency | every 100 injections |
The carrier gas must be at least 99.999% helium to prevent impurities from damaging the column.
It must be installed diagonally or vertically for optimum performance and never horizontally.
10% graphite, 90% Vespel ferrules are highly recommended to prevent thermal degradation and tailing.