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Mass Spectrometry II

Mass Spectrometry II. Ion trap. Magnetic Sector. F B. Magnetic Sector. Magnetic Sector. Ion-source. detector. +. +. +. +. +. +. +. +. Mass is determined by the time it takes the ion to move from source to detector. +. +. +. +. +. +. +. +. +. +. +. +. +. +. +. +.

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Mass Spectrometry II

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  1. Mass Spectrometry II

  2. Ion trap

  3. Magnetic Sector FB

  4. Magnetic Sector

  5. Magnetic Sector

  6. Ion-source detector + + + + + + + + Mass is determined by the time it takes the ion to move from source to detector + + + + + + + + + + + + + + + + L (length) t = + + + (velocity) - + √ (acceleration voltage) 2V Field-free flight zone Acceleration zone  = (m/z) (mass-to-charge) Time of Flight MS In a quadrupole MS masses are separated based on their flight path In a time-of-flight MS masses are separated based on their inertia

  7. 301.14 to 301.16 amu 169.09 to 169.08 amu 179.10 to 179.12 amu 193.12 to 193.14 amu 281.13 to 281.15 amu 235.16 to 235.19 amu

  8. MS Application

  9. MS Application • Environmental Issue: • Presence of bioloigcally-active compounds (pharmaceuticals…) that are not degraded in a wastewater treatment plant • Compound of interest is trimethoprim, an anti-microbial used to treat infectious diseases in humans • Analytical - want to analyze for trimethoprim • LC/GC? • Ionization source? LC – why? ESI – why? • Hypothesis • Primary treatment of wastewater with nitrifying activated sludge will degrade trimethoprim

  10. MS Application • Hypothesis • Primary treatment of wastewater with nitrifying activated sludge will degrade trimethoprim • Experiment • Small scale laboratory batch reactor was used to degrade trimethoprim • LC-ESI coupled to a single quadrupole MS to determine the unit mass of degradation products • LC-ESI coupled to an ion trap MS to determine structural features of the degradation products • LC-ESI coupled to a quadrupole time of flight MS to determine the accurate mass of the degradation products to get a chemical formula

  11. MS Application • Hypothesis • Primary treatment of wastewater with nitrifying activated sludge will degrade trimethoprim • Experiment • Small scale laboratory batch reactor was used to degrade trimethoprim • LC-ESI coupled to a single quadrupole MS to determine the unit mass of degradation products • LC-ESI coupled to an ion trap MS to determine structural features of the degradation products • LC-ESI coupled to a quadrupole time of flight MS to determine the accurate mass of the degradation products to get a chemical formula

  12. MS Application Data from LC-ESI-single quad MS MW: 290.32 g mol-1 Total ion chromatogram Degradation products Parent [M+1] Single ion chromatogram Anything strange…

  13. MS Application • Experiment • LC-ESI coupled to a single quadrupole MS to determine the unit mass of degradation products • 2 degradation products • [M+H] of 307 m/z and 325 m/z • Increased mass but earlier LC elution • Suggests oxidation • Mass difference between 291 m/z and 307 m/z is 16 m/z (oxygen) • Mass difference between 291 m/z and 325 m/z is 34 m/z (2O and 2 H)

  14. MS Application Data from LC-ESI-Ion trap MS (MS2) LC mobile phase is H2O and CH3OH 291 (trimethoprim) trapped in ion trap Accelerated/dissociated and the products detected [M+H] is 291 291 m/z → products

  15. MS Applications • Experiment • LC-ESI coupled to a single quadrupole MS to determine the unit mass of degradation products • 2 degradation products • [M+H] of 307 m/z and 325 m/z • Increased mass but earlier LC elution • Suggests oxidation • Mass difference between 291 m/z and 307 m/z is 16 m/z (oxygen) • Mass difference between 291 m/z and 325 m/z is 34 m/z • LC-ESI coupled to an ion trap MS to determine structural features of the degradation products • Parent • Demonstrates that the phenyl rings are recalcitrant to dissociation • Useful information for the ion trap analysis of the degradation products

  16. MS Application Data from LC-ESI-Ion trap MS (MS2) 307-18 Loss of water [M + H – H2O]+ Degradation product 307 m/z trapped in ion trap Accelerated/dissociated and the products detected 307 m/z → products D2O and CD3OD

  17. MS Application Data from LC-ESI-Ion trap MS (MS3) Degradation product 307 m/z trapped in ion trap Accelerated/dissociated and 289 m/z trapped in ion trap Accelerated/dissociated and the products detected Can be formed from the dissociation of 307m/z or 289 m/z 307 m/z → 289 m/z → products D2O and CD3OD

  18. MS Application Data from LC-ESI-Ion trap MS (MS3) Degradation product 307 m/z trapped in ion trap Accelerated/dissociated and 274 m/z trapped in ion trap Accelerated/dissociated and the products detected Can be formed from the dissociation of 289 m/z and 274 m/z 307 m/z → 274 m/z → products D2O and CD3OD

  19. MS Application • Experiment • LC-ESI coupled to a single quadrupole MS to determine the unit mass of degradation products • 2 degradation products • [M+H] of 307 m/z and 325 m/z • Increased mass but earlier LC elution • Suggests oxidation • Mass difference between 291 m/z and 307 m/z is 16 m/z (oxygen) • Mass difference between 291 m/z and 325 m/z is 34 m/z • LC-ESI coupled to an ion trap MS to determine structural features of the degradation products • Parent • Demonstrates that the phenyl rings are recalcitrant to dissociation • Useful information for the ion trap analysis of the degradation products • Products • Use MS3 data to propose a fragmentation pathway for 307 m/z degradation product • Structure confirmation

  20. MS Application Data from LC-ESI-Ion trap MS (MS2 and MS3) Propose fragment structures - H, - OH, - CH3

  21. MS Application • Experiment • Small scale laboratory batch reactor was used to degrade trimethoprim • LC-ESI coupled to a single quadrupole MS to determine the unit mass of degradation products • LC-ESI coupled to an ion trap MS to determine structural features of the degradation products • LC-ESI coupled to a quadrupole time of flight MS to determine the accurate mass of the degradation products to get a chemical formula • Hypothesis • Primary treatment of wastewater with nitrifying activated sludge will degrade trimethoprim • Answer • Degradation of trimethoprim is possible using nitrifying activated sludge • Degradation products identified using several MS techniques

  22. MS Application Data from LC-ESI-Ion trap MS LC mobile phase is D2O and CD3OD 296 (d-trimethoprim) trapped in ion trap Accelerated/dissociated and the products detected [M+D] is 296

  23. MS Application Data from LC-ESI-Ion trap MS H2O and CH3OH D2O and CD3OD

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