Agilent Technologies 7000 Series - High Vacuum Pressure in EI Mode

5 Operating in EI Mode
High Vacuum Pressure in EI Mode
106 7000/7010 Series TQ GC/MS Operating Manual
High Vacuum Pressure in EI Mode
The largest influences on operating pressure in EI mode are the carrier gas
(column) and CC gas flows. Table 7 lists typical pressures for various helium and
nitrogen CC gas flows. These pressures are approximate and will vary from
instrument to instrument by as much as 30%.
If the pressure is consistently higher than those listed, refer to the online help in
the Agilent MassHunter GC/MS Acquisition software for information on
troubleshooting air leaks and other vacuum problems.
Table 7 Influence of carrier and CC gas flows on ion vacuum gauge readings
CC Gas On 
N
2
= 1.5, He = 2.25

CC Gas Off
CC Gas On
N
2
= 1.5, He off
Column Flow
(mL/min)
Rough Vac High Vac Rough Vac High Vac Rough Vac High Vac
0.5 1.58 * 10
-1
1.11 * 10
-4
8.82 * 10
-2
6.05 * 10
-7
1.36 * 10
-1
1.31 * 10
-4
0.7 1.61 * 10
-1
1.10 * 10
-4
9.92 * 10
-2
7.75 * 10
-7
1.39 * 10
-1
1.31 * 10
-4
1 1.66 * 10
-1
1.10 * 10
-4
1.00 * 10
-1
8.38 * 10
-7
1.44 * 10
-1
1.31 * 10
-4
1.2 1.69 * 10
-1
1.10 * 10
-4
1.05 * 10
-1
9.38 * 10
-7
1.47 * 10
-1
1.31 * 10
-4
2 1.80 * 10
-1
1.11 * 10
-4
1.22 * 10
-1
1.36 * 10
-6
1.60 * 10
-1
1.32 * 10
-4
3 1.95 * 10
-1
1.12 * 10
-4
1.41 * 10
-1
1.82 * 10
-6
1.75 * 10
-1
1.32 * 10
-4
4 2.10 * 10
-1
1.12 * 10
-4
1.57 * 10
-1
2.33 * 10
-6
1.90 * 10
-1
1.31 * 10
-4
6 2.37 * 10
-1
1.13 * 10
-4
1.89 * 10
-1
3.29 * 10
-6
2.18 * 10
-1
1.34 * 10
-4