Is there a way to turn off the detector mid-run so that a solvent peak can be removed, while still getting peaks both before and after the solvent?

I'm decently familiar with Agilent's ChemStation software, but this is tricky. I'm developing a method for analyzing ethanol solvent impurities, and there's potentially 8 peaks. While a solvent delay works for testing everything after the solvent peak, my solvent is coming out at #3 of the 8 peaks. Is there a way to run the method and only turn off the detector for say between the 3-5 minute marks, so as to both observe all the impurities before/after the ethanol solvent without being drowned out by the solvent and to protect the MS detector from the solvent hit?


Top Replies

  • Hi  ,

    If you are using Chemstation that I see tagged in the post, you could try timed events in your MS Sim/ Scan parameters setting in the method. Timed events does have detector on and off as settable timed events. I havent tried this, so let us know the results.



  • I'll give that a try.  Thanks for the suggestion, and I'll let you know if it works.

  • Hi Rider.barnum,

    Did James answer your question?



  • I'm still trying to get this new method development working, but yes it did work.  Thanks for the suggestion, James!  Because I'm trying to look at low-level analyses of different ethanol impurities, I'm trying to fight off the myriad of siloxane peaks at the end of the method run.  I tried changing out the septum and reconditioning the column, but still there.  I'm probably going to just reduce the split ratio or increase sample inject volume to overcome what I believe is the column bleed.  It's just that the abundances are way higher than I'd expect, around the 700k range.  Any thoughts on that?  m4esti or James....any suggestions on that?
    Current brief method specs:  Sample: 95% ethanol, carrier HP helium 2mL/min, max method temp 125oC, runtime 10 min, m/z range: 29-250, injection 0.2uL, split 1:100, previous column condition at 225oC for 3 hrs.

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