Agilent Technologies 7500 ICP-MS Operator's Manual page 113

Agilent 7500 ICP-MS ChemStation Operator's Manual
Tuning
Tuning parameter Typical
QP Focus (V)
Plate Bias (V)
QP Bias (V)
4 Monitor 39(ArH), 56(ArO), and 59(Co) AMU.
5 Adjust the torch position (Torch-H, Torch-V).
Adjust the torch position to which the mass 56 signal is low and the mass 59 signal
is high.
6 Adjust the Carrier gas and the Makeup gas.
Adjust the Carrier gas and the Makeup gas to which the mass 59 signal is high.
7 Adjust the sampling depth (Smpl Depth).
Adjust the sampling depth to which the mass 39 and 56 signals are low.
8 Adjust the lens parameters.
Adjust to the mass 59 higher and the mass 39 and 56 lower. If the mass 39 and 56
signal behave the same as the mass 59 signal, there may be Fe and K contamination
in the Co tuning solution. In such case, monitor the mass 76 (ArAr) instead of the
mass 39.
9 Adjust the plasma condition.
Adjust to the parameters related to the plasma condition (RF power, Carrier gas,
Makeup gas, Sampling depth). Adjust to the mass 59 higher and the mass 39 and 56
lower.
The behavior of 39 m/z (ArH) is different from 56 m/z (ArO). Decreasing the
plasma temperature decreases ArO sensitivity asymptotically. However, ArH
sensitivity reaches a minimum and then increases at very low plasma temperatures.
Polyatomic ions at mass 40 (Ar) and 55 (ArOH or KO) behave the same as ArH.
When K, Ca, Mn and Fe are analyzed, check that you are getting low background
values for both masses 39 and 56 simultaneously.
Range
∼
0
0 5
∼
-10
-10 -5
∼
-10
-10 -5
Because the ion energy is low, it is necessary to make this value
smaller than the standard torch. Make sure to use with 0 or (+).
In the case of (-), the background will sharply rise.
Because the ion energy is low, it is necessary to add negative
voltage.
Because the ion energy is low, it is necessary to add negative
voltage.
Note
4-37