Methods 3
To create a method for positive/negative mixed mode operation
To create a method for positive/negative mixed mode operation
1Open the MSD Spray Chamber dialog box by clicking the Instrument > Set Up MSD Signals in the Method and Run Control view.
2Select
3Check that Installed Spray Chamber is also set to
4Make any other changes that are necessary for your method.
5Click the OK button.
6Open the Set up MSD Signals dialog box by clicking the Instrument > MSD Spray chamber in the Method and Run Control view.
7Modify the settings so that Signal 1 has Positive polarity and Signal 2 has Negative polarity as shown in Figure 21.
8Make any other changes that are necessary for your method.
9Click the OK button.
Fast positive/negative polarity switching is a very useful technique but it requires time for the ion chemistry to be established and the optics path to refill with ions. The gas density plays a role in the speed of refilling the ion path. The gas density is affected by source temperature. For a method running positive/negative switching, use a lower vaporizer temperature (150 to 200°C) and a lower Vcap (approximately 1000 V). These will greatly affect the quality of the results in positive/negative switching experiments.
Multimode Source for 6100 Series Single Quad LC/MS | 37 |