How to set an MS2 Scan method in Triple Quad 6460 to get proper MS2 scan spectra

Hello MS scientist, 

I am facing a problem to set an MS2 Scan method in Triple Quad 6460 instrument. I am trying to analyze caffeine at the MS2 level but I am not getting a proper MS2 scan peak. 

Please guide me with the proper method.  

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  • Hi, 

    Thank you for your suggestions. Concentration- 100ug/ml, 15ul injection volume, Mobile phase- A-0.1% FA in water, B-0.1% FA in 100% methanol. 

    Please find the Mass Hunter Quantitative software image. This image is showing just the MS spectrum.  

  • So you have a peak in the TIC at approx 14.5 minutes. What does the spectrum look like? Can you share the peak apex spectrum? The monoisotopic mass of caffeine when protonated (M+H+) is 195.1m/z but the molecule can fragment to give a product ion with a monoisotopic mass of 138.1m/z. You should look for those two masses in the spectrum. Anyway it looks like you may have your caffeine peak there - good news Smiley. Caffeine is relatively polar - on our Eclipse Plus C18 columns it typically elutes at approx 10-15% Acetonitrile. If you want an earlier elution time, simply increase the percentage of methanol you are delivering from the pump or shorten the gradient time - its not clear if you are using an isocratic or gradient method. 

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