Re-optimizing the ESI probe position
After maintenance or modification, the position of the ESI probe may require re-optimizing.
To fine-tune the ESI probe position:
- Click File > Open and open the sample-infusion tune file.
-
Click the Fluidics tab.
-
Change the sample flow path to Combined.
-
Set temperatures and gas flows for your application.
| Recommended temperatures by flow rate: | |||
|
Flow rate (mL/min) |
Source temperature (°C) |
Desolvation temperature (°C) |
Desolvation gas flow (L/h) |
|
0.000 to 0.020 |
100 | 200 | 800 |
|
0.020 to 0.100 |
120 | 350 | 800 |
|
0.101 to 0.300 |
120 | 450 | 800 |
|
0.301 to 0.500 |
150 | 500 | 1000 |
|
> 0.500 |
150 | 600 | 1200 |
-
Allow the temperatures to stabilize.
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Enter a sample infusion flow rate of 10 μL/min, and start the flow .
7. Start the external (LC) flow.
Tip: In combined (LC and sample-infusion mode), the sample is diluted by the ratio of the LC flow rate to the infusion flow rate. If the mass of interest is not sufficiently intense for tuning, increase the intensity of the signal, as necessary, by increasing the sample flow or concentration.
Notice: If you position the probe too close to the sample cone, nonlinear data, sample suppression, and the need for frequent source cleaning can result.
8. Maximize the peak intensity by turning the Vernier probe adjuster on the probe's mounting flange.
Tip: To ascertain the probe's position, set the capillary voltage to zero. If the signal intensity fails to drop to less than 10% of that observed with optimum capillary voltage, move the probe away from the sample cone slightly. Return the capillary voltage to its previous setting and observe the signal intensity. Repeat as necessary.
9. Adjust the capillary voltage for maximum sensitivity.
10. Optimize the capillary protrusion using the knurled knob atop the ESI probe.
11. Optimize the sample cone voltage for maximum intensity.
12. If advised to do so by your applications specialist, adjust the cone gas flow for your sample requirements.
Tip: Starting from a value of 0, increase the cone gas flow in increments of 50; allow the flow rate to stabilize after each adjustment. To minimize the formation of solvent ion clusters, set the gas flow to the highest value that does not significantly reduce the peak intensity. For samples in involatile or complex matrix applications, using cone gas can also extend the source's cleaning interval.
13. Click File > Save As and save the file with a new name.
id79485, CYCIMS, Electrospray, MLYNX, MLYNXV41, SUPMM