Agilent Technologies 7500 ICP-MS - Information on Sensitivity Adjustment

4-46
Agilent 7500 ICP-MS ChemStation Operator’s Manual
Tuning
resolution are not good, adjust it up to -2 V.
QP bias needs to be more positive than the OctP bias by the value shown as
below:
• In standard mode: 2 to 4 V (Block polyatomic ions produced from the residual
gas in the ion lens chamber.)
• In reaction mode: 1 to 2 V (Block polyatomic ions produced from the residual
gas in the ion lens chamber and the Ar-related polyatomic ions, which lost
energy by reaction. If the QP Bias is set to a high voltage, the sensitivity will
also decrease.)
Reaction Cell
• Reaction Mode
Switch between standard mode, cool mode and reaction mode. When a check
box is ON, it is in reaction mode and when a check box is OFF, it's in standard
mode, cool mode
• H
2
Gas
Adjust the flow rate of hydrogen gas (H
2
) used as the reaction gas. The higher
the flow rate of H
2
gas, the lower the sensitivity of a sample and the intensity of
the background. Adjust the flow rate in order to make the background low
enough and to get the necessary level of sensitivity.
• He Gas
Adjust the flow rate of helium gas (He) used as the reaction gas. The higher the
flow rate of He gas, the lower the sensitivity of a sample and the intensity of the
background. Adjust the flow rate in order to make the background low enough
and to get the necessary level of sensitivity.
• Optional Gas (option)
On the Agilent 7500ce, if an optional gas line is added other than H
2
gas and He
gas, another type of gas can be introduced.
Information on Sensitivity Adjustment
The Agilent 7500ce can be used with no gas (standard mode) or may use a reaction
gas (reaction mode). In reaction mode, either hydrogen gas (H
2
mode) or helium
gas (He mode) is used as a reaction gas.
Even using reaction mode (H
2
mode and He mode) is used, if tuning is done in the
standard mode beforehand, tuning can be completed easily just by a partial change