To set up a SCIEX high flow source for microflow LC (Turbo V ion source, DuoSpray source or IonDrive Turbo V ion source), first you must replace the wider bore electrodes with more narrow bore hybrid electrodes. Note with the OptiFlow Turbo V ion sources, there are pre-set probes and electrodes that are already optimized for low flow LC applications.
First, remove the original electrode. Remove the probe from the source and unscrew the black nut at the top of the probe and pull out the high flow metal electrode. Also remove the spring.
Next, take the taller spring that comes with the microflow hybrid electrode (25 µm P/N 5028467: 50 µm P/N 5028466) and place it in the probe. Now the hybrid electrode can be slotted into the probe. Be careful to line up the flat sides of the PEEK body of the electrode with the flat sides in the probe. Screw the black nut down onto the probe and this will push the electrode in. The black O-ring will slowly be compressed to make the seal. If you have to apply too much pressure, first check that you have the electrode aligned correctly, and next try wetting the O-ring with a drop of water. Screw the black nut down until you just start to see the electrode protruding out of the bottom of the probe.
Place the probe back into the source and activate the hardware profile. While infusing the PepCalMix at the desired flow rate, start acquiring data on the sample in Manual Tune, to monitor intensity and stability of signal (see SOP document that comes with kit for acquisition details). Set the source conditions on the Source/Gas Tab as shown (reasonable starting conditions for 5uL/min are shown below).
Slowly turn the black nut clockwise to increase the protrusion of the electrode (start with the electrode flush with the bottom of the probe). Turn the nut in increments of 1/8th of a turn and pause to see the signal stabilize. If the signal increases, turn again, if not the protrusion is good (should be roughly 1mm protrusion).
Now that the protrusion is optimized, you can adjust the source conditions slightly to get the best signal and stability. For 5uL/min, the values will be close to the values shown above. Avoid adjusting the temperature too hot, better electrode lifetime will be achieved. Transfer these settings into your acquisition method and you are ready to run microflow LC-MS!