Function Switching With Fast Asynchronous Acquisition

A method as claimed in any preceding claim, wherein said step of switching a state or mode of said mass spectrometer comprises switching the polarity of an ion source.

A method as claimed in any preceding claim, wherein said step of switching a state or mode of said mass spectrometer comprises fragmenting or reacting parent ions to produce fragment or product ions.

A method as claimed in any preceding claim, wherein said step of switching a state or mode of said mass spectrometer comprises switching the transmission characteristics of a mass, mass to charge ratio, ion mobility or differential ion mobility filter or separator.

A method as claimed in any preceding claim, wherein said step of switching a state or mode of said mass spectrometer comprises selecting a different species of parent or precursor ion.

A method as claimed in any preceding claim, wherein said step of switching a state or mode of said mass spectrometer comprises selecting a different Collision Induced Dissociation collision energy.

A method as claimed in any preceding claim, wherein said step of switching a state or mode of said mass spectrometer comprises selecting a different fragmentation or reaction state of said mass spectrometer so that different ions are fragmented or reacted and/or ions are fragmented or reacted to different degrees.

A method as claimed in any preceding claim, wherein said step of switching a state or mode of said mass spectrometer comprises switching or altering an operational parameter of said mass spectrometer.

A method as claimed in any preceding claim, wherein said stream of mass spectral data which is acquired is substantially continuous.

A method as claimed in any preceding claim, wherein said step of acquiring a stream of mass spectral data comprises continuously acquiring a stream of mass spectral data.

A method as claimed in any preceding claim, wherein said step of acquiring a stream of mass spectral data comprises substantially continuously acquiring mass spectral data without dividing a mass spectral data acquisition period into a plurality of mass spectral data acquisition windows separated from each other by an equilibration delay time period during which time period:

• (i) no mass spectral data is acquired;
• and/or (ii) said mass spectrometer is allowed to equilibrate;
• and/or (iii) said mass spectrometer is switched between states or modes.

A method as claimed in any preceding claim, wherein said step of acquiring a stream of mass spectral data comprises substantially continuously acquiring mass spectral data without pausing the acquisition of said mass spectral data immediately before and/or during and/or immediately after a state or mode of said mass spectrometer has been switched.

A method as claimed in any preceding claim, further comprising:

• repeatedly switching said mass spectrometer between a first state or mode and a second state or mode, wherein said mass spectrometer is in said first state or mode for a time T1 and is in said second state or mode for a time T2;
• wherein said stream of mass spectral data is continuously acquired over a time period>T1 and >T2.

A method as claimed in any preceding claim, further comprising mass analysing said first ions and/or said second ions.

A method as claimed in any preceding claim, wherein during a single mass spectral data acquisition period a state or mode of said mass spectrometer is switched a plurality of times.

A method as claimed in any preceding claim, wherein a state or mode of said mass spectrometer is repeatedly switched with a frequency f1 and wherein mass spectral data is acquired during acquisition periods with a frequency f2, wherein f2<f1.

A method as claimed in any preceding claim, wherein said stream of mass spectral data is acquired substantially independently of any switching of a state or mode of said mass spectrometer.

A method as claimed in any preceding claim, wherein:

• said stream of mass spectral data is acquired during a mass spectral data acquisition period;
• and
• said acquisition period is substantially asynchronous with and/or is not synchronised with the switching of said mass spectrometer between states or modes.

A method as claimed in any previous claim, wherein said step of post-processing said stream of mass spectral data comprises detecting ion peaks in said stream of mass spectral data and determining a plurality of ion peak times and a plurality of ion peak intensities associated with said stream of mass spectral data.

A method as claimed in any previous claim, wherein said step of post-processing said stream of mass spectral data comprises determining which portions or sample periods of said stream of mass spectral data relate to said first ions or to said second ions.

A method as claimed in any preceding claim, wherein said step of post-processing said stream of mass spectral data comprises determining which portions or sample periods of said stream of mass spectral data relate to both said first ions and to said second ions, and rejecting those portions or sample periods.

A method as claimed in any preceding claim, wherein said step of post-processing said stream of mass spectral data comprises producing a mass spectrum for (i) said first ions and/or (ii) said second ions by combining portions or sample periods of said stream of mass spectral data determined to relate to said first ions and/or by combining portions or sample periods of said stream of mass spectral data determined to relate to said second ions.

A method as claimed in any previous claim, wherein said step of post-processing said stream of mass spectral data comprises producing reconstructed mass chromatograms for ion peaks appearing in said stream of mass spectral data.