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2
Mass Reference Solution
To enable reference mass correction
1 In the MassHunter Acquisition program, in the Reference Mass tab, enter
2 Repeat for the other IRM compound if it is used.
3 Check the Enable Reference Mass box.
4 Set the acquisition mass range in MS mode to be wide enough to include the
5 Save the method.
Shortly after loading the IRM solutions, the ion signals stabilize at around
20,000 to 150,000 counts abundance when the instrument is operated at
approximately 5,000 to 10,000 transients per spectrum.
Actual values depend primarily on:
For best results:
The ion signals from the IRM compounds decay quickly at first but stabilize at
a lower usable level for days. An increase to the drying gas temperature
increases the abundances for the IRM compounds but also leads to a faster
rate of decline of the IRM abundances. The IRM response can be reduced when
using mobile phase compositions that contain high organic content,
particularly high amounts of acetonitrile. (This is especially true for methyl
stearate.)
50
the m/z value. Mark the check the box in front of the entry.
reference masses selected.
•
the amount that was loaded
•
cleanliness of the interface assembly
•
operating parameters used for the MS
•
mobile phase composition
•
number of transients per scan
• Keep the abundances above 5,000 counts for all scan speeds to obtain
adequate ion statistics.
• Keep the abundances below the value of 90 * (number of transients per
scan) to avoid saturation effects.
• For 2 scans/second (4,880 transients/scan), the desirable range is
between 5,000 to 440,000 counts abundance.
Nanospray Ion Source User Guide
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