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Running a TOF LC/MS Method

Running a Method

  1. Confirm that the Context is set to Acquisition
  2. The most common layout is the default.lyt.  This allows the run method to be on the left monitor and the spectrum and chromatogram plots to be shown on the right monitor.  You may find a layout that suits your needs better, but this is a good starting place.
  3. If you are using an existing method it may be found in the drop down Method list which holds recently used methods.  Other stored methods can be found using the tool bar at the top of the screen.  Pull down Method menu and select Open.  Many methods used as of January 2016 are found in the Data folder, in the sub folder Data.  As users increase this organization may change.
  4. A new method may also be written, Begin by selection Method on the top tool bar, using the pull down menu select New.
  5. A current method can be edited by opening the method and saving changes under a new name.
  6. In the Method Editor portion of the screen there is a tool bar which allows each parameter of the method be set.
  7. Properties shows the location of your file, allows pre and post run script (such as all pumps off or divert MS to waste), and a place to add a description of the method.
  8. DA allows for the detection method to be paired with a data analysis method.
  9. HiP Sampler can set the injection volume
  10. The Binary Pump tab allows the flow rate, solvent selection, solvent mixing percents,
  11. Column Comp can adjust the temperature of the columns.
  12. DAD sets the wavelengths of light detected by the diode array and the reference bandwidth can be set as a background absorption to be subtracted from the selected wavelengths.
  13. The TOF tab adjusts the MS parameters.  Ion source should match the source attached to the MS,  Under Ion Polarity select Positive or Negative, check that the LC Stream is going to the mass spec (MS) and not the waste.
  14. Click Apply.  Note: Apply now sends only the information in that box to the instrument, such as changing only where the flow is directed, Apply sends all the settings in all the method tabs to the instrument,
  15. Save new method under a new name.  From the Method drop down select save as. If there is an error in your method a warning will appear now.
  16. A single sample can be run from the Sample Run tab at the bottom of the screen or a series of samples can be run using the auto sampler from the Worklist tab.
  17. From either the Sample Run or Wordlist tab the run is started by clicking to black triangle and stopped by clicking the black square.
  18. Clicking F1 while in any window will bring up a help menu specific to that topic.

Introducing Samples

  1. Manual injection-Samples can be injected without using the LC.  The tubing that lead from the outlet of the LC to the inlet of the detector’s spray nozzle can be disconnected and connected directly to a syringe.  The syringe is then placed in the kdScientific™ automatic pump.  The pump can be set to the desired rate and final volume.  It is recommend that the volume selected is slightly less than the total volume of the syringe.
  2. Auto Sampler-Multiple samples can be run using the auto sampler.  The auto sampler uses small vials and caps that are placed in the auto sampler tray.  Check that the tray you are using matches the tray in your method.  The tray positions are numbered front to back and left to right.  For example the column on the left begins at the front of the tray and is numbered one through ten front to back.  The second column from the left is numbered eleven through twenty front to back.
  3. Through LC-Samples may also be eluted through chromatography columns and directly on to the MS.  When using the LC double check the Method to ensure that the elution from the LC is going to the MS instead of to the waste.