How to check the presence of a charging effect on a specific compound ?

For research use only. Not for use in diagnostic procedures.

Answer

Procedure to perform a charging effect test on a specific compounds coupled with a repeatability test:

1) Prepare sufficient quantity of a mid-range standard to be used for the repeatability and charging effect tests.

2) Create a method called "Switch Polarity". To do this, open your usual method in POS or NEG mode. Change the polarity to the opposite of that normally used, then save the result as "Switch Polarity".

3) Equilibrate the system for a sufficient period using the "Normal" method.

4) Once the equilibration is complete, immediately run a batch with the following sequence:
    → Standard mid-range + "Switch Polarity" method
    → Standard mid-range + "Switch Polarity" method
    → (Standard mid-range + "Normal" method) x10
    → Standard mid-range + "Switch Polarity" method
    → Standard mid-range + "Switch Polarity" method
    → (Standard mid-range + "Normal" method) x10

5) Send all the raw data (.wiff2 / .wiff / wiff.scan) to the SciexNow team.

• If you have no charging effect on a specific mass, you will have the following profile:

• If you have a charging effect on a specific mass, you will have the following profile:

The presence of a charging effect implies to clean the MS.