Plasma Condition - Agilent Technologies 7500 ICP-MS Operator's Manual

N O T E
Agilent 7500 ICP-MS ChemStation Operator's Manual
Tuning
Typical value of Sensitivity and RSD (Using the normal torch)
Counts / 10 ppb
Mass Integ. Time = 0.1sec
7
Li
89
Y >16000
205
Tl

Plasma Condition

• RF Power
Controls RF power supplied to the load coil. A higher RF power increases the
sensitivity and reduces oxide and doubly charged ions. However, the sensitivity
of lighter masses may be decreased when the RF power is too high.
• RF Matching
Adjusts reflected RF returned from the load coil.
To reduce the reflected power, use of the automatic adjustment function is
recommended. To use the automatic adjustment function, select Tune>>RF
Matching on the Tuning window, and then follow the displayed dialog box.
If you adjust the RF Matching manually, use only the scroll arrows to change this
value. If you click on the scroll bar itself, the instrument will turn off the plasma.
Adjust until the RF reflected power meter reads as low as possible. Standard value
for RF matching is approximately 1.6 to 2.0 V.
• Smpl Depth
Controls distance between the edge of the load coil and the tip of the sampling
cone. A shorter sampling depth increases sensitivity, but oxide level increases as
well. If the torch is too far from the interface opening for the plasma flow to sus-
tain the interface pressure, the plasma is turned off.
• Torch-H, Torch-V
Controls torch position. The Torch-H and Torch-V parameters measure the
horizontal and vertical movement of the torch relative to the interface. Adjusts to
get the highest sensitivity for all masses. When the sampling depth is changed,
4-8
RSD
>6400 <15%
<15%
>9600 <15%