Agilent Technologies 7500 ICP-MS Operator's Manual page 154

Agilent 7500 ICP-MS ChemStation Operator's Manual
Tuning
g.Readjust the Omega Lens-cs, QP Focus, and OctP RF to obtain best
sensitivity.
h.(Background Check) Aspirate fresh DI water and measure the background
of mass (58 amu), which is to be measured in He mode. If the count of 58
amu is too high, increase 0.4 mL/min of He flow rate, and then repeat step e
to step g.
i. If the sensitivity is low, change the Omega Bias-cs and the Cell Exit to a
lower voltage. In this case, sometimes, the background may increase.
Monitor the background when adjusting.
Typical values of Tuning Parameters in the He Mode
(with ShieldTorch, Micro Flow Nebulizer, self-aspiration)
Parameter
RF Power (W)
Sampling Depth (mm)
Carrier Gas (L/min)
Makeup Gas (L/min)
PeriPump 1 (rps)
ºC
S/C temp ( )
Extract 1 (V)
Extract 2 (V)
-cs
Omega Bias (V)
-cs
Omega Lens (V)
Cell Entrance (V)
QP Focus (V)
Cell Exit (V)
OctP RF (V)
OctPBias (V)
QP Bias (V)
He Gas (ml/min)
4-78
Typical Value Adjustment
1500 Normally used 1500
8
0.8
0.45
0.1
2
Normally used at 2
5.4
-100
-40
8.6
-30
-12
-40
180
-18 Normally used -18
-16 -Normally used -16
3.5
7 to 10
0.6 to 1.0
0.3 to 0.7
ºC
4 to 8
-150 to -60
-50 to -30
5 to 10
-50 to -30
-20 to 0
-80 to -20
100 to 200
2.5 to 5.5