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106
5977 Series MSD Operation Manual
4
Operating in Chemical Ionization (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 5977 Series MSD with
methane reagent gas before attempting to use other reagent gases.
Changing the reagent gas from methane to either isobutane or ammonia
changes the chemistry of the ionization process and yields different ions. The
principal chemical ionization reactions encountered are described in general
in the 5977 Series Concepts Guide. If you are not experienced with chemical
ionization, we suggest reviewing that material before you proceed.
C A U T I O N
Do not use nitrous oxide as a reagent gas. It radically shortens the life span of the
filament.
C A U T I O N
Not all setup operations can be performed in all modes with all reagent gases. See
for details.
Table 19
Reagent gases
Reagent gas/mode
Reagent ion masses
PFDTD
Calibrant ions
Flow adj ions: Ratio
EI/PCI/NCI MSD Performance turbo pump
Recommended flow: 20% PCI 40% NCI
Methane/PCI
17, 29, 41
*
41, 267, 599
28/27: 1.5 – 5.0
Methane/NCI
17, 35, 235
†
185, 351, 449
N/A
Isobutane/PCI
39, 43, 57
N/A
57/43: 5.0 – 30.0
Isobutane/NCI
17, 35, 235
185, 351, 449
N/A
Ammonia/PCI
18, 35, 52
N/A
35/18: 0.1 – 1.0
Ammonia/NCI
17, 35, 235
185, 351, 517
N/A
*
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.
Содержание G7035A
Страница 1: ...Agilent Technologies Agilent 5977 Series MSD Operation Manual ...
Страница 30: ...30 5977 Series MSD Operation Manual 1 Introduction ...
Страница 88: ...88 5977 Series MSD Operation Manual 3 Operating in Electron Ionization EI Mode ...
Страница 112: ...112 5977 Series MSD Operation Manual 4 Operating in Chemical Ionization CI Mode Figure 18 PCI autotune report ...
Страница 114: ...114 5977 Series MSD Operation Manual 4 Operating in Chemical Ionization CI Mode Figure 19 NCI autotune ...
Страница 170: ...170 5977 Series MSD Operation Manual 6 CI Maintenance ...
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Страница 172: ... G3870 90003 G3870 90003 Agilent Technologies Agilent Technologies Inc Printed in USA February 2013 ...