Methods and apparatus for mass spectrometry

A method of mass spectrometry comprising the steps of:

• providing an ion source which generates ions;
• filtering said ions so that substantially only ions having a mass-to-charge ratio greater than a first value are transmitted, said first value being between 100 and 500;
• passing the filtered ions to a fragmentation means operated in a first mode with an applied voltage ≧15V wherein at least a portion of the filtered ions are fragmented to produce daughter ions;
• mass analysing at least some of the ions which have passed through said fragmentation means operating in said first mode;
• characterised in that said method further comprises the steps of:
• identifying as daughter ions, at least some ions which are determined to have mass-to-charge ratios less than said first value;
• wherein if one or more daughter ions are determined to be present, then said method further comprises the step of determining whether said one or more daughter ions correspond with one or more predetermined daughter ions, and wherein if it is determined that said one or more daughter ions does correspond with one or more predetermined daughter ions, then said method further comprises the steps of:
• operating said fragmentation means in a second mode with an applied voltage ≦5V wherein substantially less of aid ions are fragmented than in said first mode;
• and then
• mass analysing at least some of the ions which have passed through said fragmentation means operating in said second mode.

A mass spectrometer comprising:

• an ion source for generating ions;
• a multi-element ion optical lens for filtering ions so that ions having a mass-to-charge ratio within a first range are substantially transmitted and so that the transmission of ions having a mass-to-charge ratio outside of said first range is substantially reduced;
• a fragmentation means arranged and adapted to be operated in a first mode wherein at least a portion of the ions received by said fragmentation means are fragmented to produce daughter ions;
• a mass analyser for mass analysing at least some of the ions which have passed through said fragmentation means operating in said first mode;
• and
• a control system for controlling said mass spectrometer;
• characterised in that:
• said control system is arranged to identify as daughter ions, at least some ions which are determined to have a mass-to-charge ratio which falls outside of said first range, wherein if one or more daughter ions are determined to be present, then said control system determines whether said one or more daughter ions correspond with one or more predetermined daughter ions, and wherein if said control system determines that said one or more daughter ions does correspond with one or more predetermined daughter ions, then said control system switches said fragmentation means so as to operate in a second mode wherein substantially less of the ions received by said fragmentation means are fragmented than in said first mode and whereupon said mass analyser is arranged to mass analyse at least some of the ions which have passed through said fragmentation means operating in said second mode.

A mass spectrometer comprising:

• an ion source for generating ions;
• a multi-element ion optical lens for filtering ions so that ions having a mass-to-charge ratio greater than a first value are substantially transmitted and so that the transmission of ions having a mass-to-charge ratio less than said first value is substantially reduced, said first value being between 100 and 500;
• a fragmentation means arranged and adapted to be operated in a first mode with an applied voltage ≧15V wherein at least a portion of the ions received by said fragmentation means are fragmented to produce daughter ions;
• and
• a mass analyser for mass analysing at least some of the ions which have passed through said fragmentation means operating in said first mode;
• wherein:
• said mass spectrometer is configured to identify as daughter ions, at least some ions which are determined to have a mass-to-charge ratio which is less than said first value, wherein if one or more daughter ions are determined to be present, then said mass spectrometer is arranged to determine whether said one or more daughter ions correspond with one or more predetermined daughter ions, and wherein if it is determined that said one or more daughter ions does correspond with one or more predetermined daughter ions, then said mass spectrometer is arranged and adapted to switch said fragmentation means so as to operate in a second mode with an applied voltage ≦5V wherein substantially less of the ions received by said fragmentation means are fragmented than in said first mode and whereupon aid mass analyser is arranged to mass analyse at least some of the ions which have passed through said fragmentation means operating in said second mode.

A method of mass spectrometry comprising the steps of:

• providing an ion source which generates ions;
• characterised in that said method further comprises the steps of:
• passing the ions to a fragmentation means which operates in at least a first mode wherein at least a portion of the ions are fragmented to produce daughter ions and a second mode wherein substantially less of the ions are fragmented than in said first mode;
• mass analysing at least some of the ions which have passed through said fragmentation means operating in said first mode;
• mass analysing at least some of the ions which have passed through said fragmentation means operating in said second mode;
• identifying at least one daughter ion and at least one candidate parent ion;
• and
• determining whether:
• (i) said at least one daughter ion corresponds with one or more predetermined daughter ions;
• and/or (ii) said at least one daughter ion and said at least one candidate parent ion could be related by the loss of a predetermined ion or neutral particle.

A method of mass spectrometry comprising the steps of:

• providing an ion source which generates ions;
• characterised in that said method further comprises the steps of:
• passing the ions to a fragmentation means which operates in at least a first mode with an applied voltage ≧15V wherein at least a portion of the ions are fragmented to produce daughter ions and a second mode with an applied voltage ≦5V wherein substantially less of the ions are fragmented than in said first mode;
• mass analysing at least some of the ions which have passed through said fragmentation means operating in said first mode;
• mass analysing at least some of the ions which have passed through said fragmentation means perating in said second mode;
• identifying at least one daughter ion and at least one candidate parent ion;
• and
• determining whether:
• (i) said at least one daughter ion corresponds with one or more predetermined daughter ions;
• and/or (ii) said at least one daughter ion and said at least one candidate parent ion could be related by the loss of a predetermined ion or neutral particle.

A mass spectrometer comprising:

• an ion source for generating ions;
• a fragmentation means switchable between at least a first mode wherein at least a portion of the ions received by said fragmentation means are fragmented to produce daughter ions and a second mode wherein substantially less of the ions are fragmented than in said first mode;
• a mass analyser for mass analysing at least some of the ions which have passed through said fragmentation means operating in said first mode and for mass analysing at least some of the ions which have passed through said fragmentation means operating in said second mode;
• and
• a control system for controlling said mass spectrometer;
• wherein said control system is arranged to identify at least one daughter ion and at least one candidate parent ion and to determine whether:
• (i) said at least one daughter ion corresponds with one or more predetermined daughter ions;
• and/or (ii) said at least one daughter ion and said at least one candidate parent ion could be related by the loss of a predetermined ion or neutral particle.

A mass spectrometer comprising:

• an ion source for generating ions;
• a fragmentation means switchable between at least a first mode with an applied voltage ≧15V wherein at least portion of the ions received by said fragmentation means are fragmented to produce daughter ions and a second mode with an applied voltage ≦5V wherein substantially less of the ions are fragmented than in said first mode;
• and
• a mass analyser for mass analysing at least some of the ions which have passed through said fragmentation means operating in said first mode and for mass analysing at least some of the ions which have passed through said fragmentation means operating in said second mode;
• wherein said mass spectrometer is configured to identify at least one daughter ion and at least one candidate parent ion and to determine whether:
• (i) said at least one daughter ion corresponds with one or more predetermined daughter ions;
• and/or (ii) said at least one daughter ion and said at least one candidate parent ion could be related by the loss of a predetermined ion or neutral particle.