To Use Other Reagent Gases - Agilent Technologies 5977B Series Operating Manual

5 Operating in CI Mode

To Use Other Reagent Gases

This section describes the use of isobutane or ammonia as the reagent gas. You
should be familiar with operating the CI-equipped 5977B Series MSD with
methane reagent gas before attempting to use other reagent gases.
Do not use nitrous oxide as a reagent gas. It radically shortens the life span of the
C A U T I O N
filament.
Changing the reagent gas from methane to either isobutane or ammonia
changes the chemistry of the ionization process and yields different ions. The
principal CI reactions encountered are described in general in the 5977B
Series Concepts Guide. If you are not experienced with CI, we suggest
reviewing that material before you proceed.
Not all setup operations can be performed in all modes with all reagent gases. (See
C A U T I O N
Table 14
Table 14 Reagent gases


Reagent gas/mode
Methane/PCI
Methane/NCI
Isobutane/PCI
Isobutane/NCI
Ammonia/PCI
Ammonia/NCI
* There are no PFDTD ions formed with any reagent gas but methane. Tune with methane and use the same parameters for
the other gas.
† There are no negative reagent gas ions formed. To pretune in negative mode, use background ions: 17 (OH-), 35 (Cl-), and
235 (ReO3-). These ions cannot be used for reagent gas flow adjustment. Set the flow to 40% for NCI and adjust as 
necessary to get acceptable results for your application.
132
for details.)


Reagent ion masses
*
17, 29, 41
†
17, 35, 235
39, 43, 57
17, 35, 235
18, 35, 52
17, 35, 235

Flow adj ions: Ratio
EI/PCI/NCI MSD Turbo pump 
PFDTD
Calibrant ions Recommended flow: 20% PCI 40% NCI
41, 267, 599 28/27: 1.5 – 5.0
185, 351, 449 N/A
N/A 57/43: 5.0 – 30.0
185, 351, 449 N/A
N/A 35/18: 0.1 – 1.0
185, 351, 517 N/A
5977B Series MSD Operating Manual
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