Hi-Resolution Mass Spectrometer

The Agilent LC-QTOF is located in Chem 175.  The instrument is used to separate components based on their affinity for the stationary phase of the LC column, while the quadrupole time-of-flight MS provides high resolution analysis of the separated compound based on highly accurate time-of-flight measurements.  This provides mass to charge ratios reportable to 4 decimal places.  QTOF is a valuable confirmation technique for synthesis and drug discovery because the chance that a different compound has the same exact mass is extremely low.

LC system: Agilent 1260 Infinity II Prime


*800 bar pump, 0.1 - 5.0 ml/min flow rate

*Heated column compartment

*66 vial autosampler, 0.1 - 40.0 ul injection volume



MS system: Agilent 6545B QTOF


*Agilent Jet Stream dual ESI source: analysis of positively or negatively charged ions by electrospray ionization (ESI); reference nebulizer continually introduces reference mass solution to provide drift correction; superheated nitrogen concentrates ions and increases sensitivity


*Quadrupole time-of-flight instrument provides resolution of ~20,000 (100 m/z) - 45,000 (>1000 m/z) that is independent of acquisition rate

*MS mode allows all ions to be transmitted through quadrupole

*MS/MS mode allows only selected ions to pass through quadrupole.  Ions are then fragmented in collision cell for further characterization

*Instrument can operate in 1700 m/z, 3200 m/z, and 10000 m/z mass range

*Extended dynamic range mode uses high gain and low gain channel to provide up to 5 orders of linear dynamic range.  Results of each channel are stitched together to create the resulting spectrum.  Both trace and bulk components in a sample can be observed.  The resolution is cut in half using this mode.

*Acquisition rate of up to 50 spectra/sec for MS and 33 spectra/sec for MS/MS

*Mass accuracy as low as 0.8 ppm for MS and <2 ppm for MS/MS

*Femtogram scale sensitivity

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