Method optimization
PlasmaQuant MS product family
82
8.4
Optimize the iCRC gas flows
When running in iCRC-He or iCRC-H
2
mode the gas flow rates need to be optimized to
ensure best analytical results. The amount of the iCRC gas required to remove the
interferences may vary, depending on the type of samples and interfering ions. The
use of more iCRC gas could also result in a loss of analyte sensitivity due to excessive
loss of ion energy in collisions with the iCRC gas. Hence, care needs to be taken when
adjusting the gas flow rate. Do not use more iCRC gas than necessary; otherwise the
analyte sensitivity will be reduced.
Fig. 46 Signals of analyte, interference and analyte/interference ratio
In general, hydrogen gas is used to remove plasma based interferences, such as
40
Ar
16
O
+
,
40
Ar
35
Cl
+
, and
40
Ar
40
Ar
+
. Helium gas is used to remove sample/matrix based
interferences, such as
35
Cl
16
O
+
and
35
Cl
16
O
1
H
+
.
When should you optimize the iCRC gas flows?
When analyzing any new and complex sample matrix
After any routine maintenance
100 mg/L Analytik Jena Internal Standard Solution (containing Li, Sc, Y, In, Tb, Bi,
prepared in 5 % HNO
3
)
Solution A (prepared from Analytik Jena Internal Standard Solution with 10 µg/L
Li, Sc, Y, In, Tb, Bi), used for iCRC gas flow optimization
Solution B (prepared from Analytik Jena Internal Standard Solution with 10 µg/L
Li, Sc, Y, In, Tb, Bi + analytes of interest, e.g. 1 µg/L V, Cr, Fe, As, Se), used for iCRC
gas flow verification
Solution A and B are prepared from the Internal Standard Solution in a mixed acid
matrix of HNO
3
and HCl (1 % of each).
Check that the iCRC gases (H
2
and/or He) are connected properly, and ensure the
gas supply is switched on.
Select A
CTIONS
I
CRC
G
AS
S
UPPLY
P
URGE
to verify the iCRC gas system is ready.
Required Solutions
Preparation