4-78
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 Typical Value Adjustment
RF Power (W) 1500 Normally used 1500
Sampling Depth (mm) 8 7 to 10
Carrier Gas (L/min) 0.8 0.6 to 1.0
Makeup Gas (L/min) 0.45 0.3 to 0.7
PeriPump 1 (rps) 0.1
S/C temp (
ºC)
2
Normally used at 2ºC
Extract 1 (V) 5.4 4 to 8
Extract 2 (V) -100 -150 to -60
Omega Bias
-cs (V)
-40 -50 to -30
Omega Lens-cs (V)
8.6 5 to 10
Cell Entrance (V) -30 -50 to -30
QP Focus (V) -12 -20 to 0
Cell Exit (V) -40 -80 to -20
OctP RF (V) 180 100 to 200
OctPBias (V) -18 Normally used -18
QP Bias (V) -16 -Normally used -16
He Gas (ml/min) 3.5 2.5 to 5.5
To Next Page
Loading...
