Prevention Of Em Deterioration - Agilent Technologies 7500 ICP-MS Operator's Manual

Agilent 7500 ICP-MS ChemStation Operator's Manual
Creating a Method

Prevention of EM deterioration

When higher signals are analyzed for a long time with too high sensitivity, the EM
may deteriorate fast. EM deterioration causes the drift of the signal and the lifetime
of the EM may be shorten. The following methods will prevent EM deterioration:
• Set suitable integration time
Shorten the integration time according to the suitable setting required for the pro-
duction of reproducible data. The following table shows the recommended value
of integration time for the prevention of the EM deterioration. Please refer to it
and set the integration time for each mass.
The Standard of
concentration *
< a few 10 ppb
A few 10 ppb to
approx.100ppb
> approx.100ppb
These values are only for reference, so please set the longer integration time
according to your application, if necessary. For more information regarding the
settings for integration time, please refer to Chapter 5, "Creating a method" and
the Application Handbook.
• Decrease the intensity
When the group of signals that you want to analyze is large, high sensitivity is not
required. It is recommended to decrease the sensitivity. If you want to decrease
the intensity, adjust the ion lens voltage (not EM voltage). To adjust the ion lens
voltage, see "Tuning for Sensitivity" in this chapter.
Recommended Value for Integration Time
Counts
0 to 500kcps
500kcps to 1Mcps
1Mcps to 4Gcps
Integration Time
per Point
> 0.1sec
0.01sec
0.01sec
* the sensitivity is 10,000 cps/ppb
Detector Mode
Pulse
Pulse
Analog
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