Methods and systems are provided herein for varying the CoV about a nominal CoV-apex while monitoring the ion of interest corresponding to the nominal CoV-apex as it is transmitted by a DMS. In various aspects, the CoV can be swept or stepped across a series of values during the injection of ions into the DMS such that a composite spectra of the ion of interest transmitted by the DMS (or its product ions following one or more stages of fragmentation) can be generated so as to include the transmission of the particular ion at a CoV with optimum sensitivity (i.e., if distinct from the CoV-apex), thereby improving the robustness, accuracy, and/or selectivity during experimental conditions relative to known DMS techniques, which typically used a fixed CoV value for each ion of interest.

A method of mass spectrometry or ion mobility spectrometry is disclosed in which analyte ions of a desired charge state are isolated. The method comprises: separating analytes according to their electrophoretic mobility; ionising the analytes; and mass filtering the resulting analyte ions, wherein the mass to charge ratios of the ions transmitted by a mass filter are varied as a function of the electrophoretic mobility and according to a predetermined relationship such that substantially only ions having said desired charge state are transmitted by the mass filter.

A method of analysis using mass spectrometry and/or ion mobility spectrometry is disclosed comprising: (a) using a first device to generate smoke, aerosol or vapour from a target in vitro or ex vivo cell population; (b) mass analysing and/or ion mobility analysing said smoke, aerosol or vapour, or ions derived therefrom, in order to obtain spectrometric data; and (c) analysing said spectrometric data in order to identify and/or characterise said target cell population or one or more cells and/or compounds present in said target cell population.

A method of analysis using mass spectrometry and/or ion mobility spectrometry is disclosed comprising: (a) using a first device to generate smoke, aerosol or vapour from a target in vitro or ex vivo cell population; (b) mass analysing and/or ion mobility analysing said smoke, aerosol or vapour, or ions derived therefrom, in order to obtain spectrometric data; and (c) analysing said spectrometric data in order to identify and/or characterise said target cell population or one or more cells and/or compounds present in said target cell population.

In a system for affinity selection by mass spectrometry, wherein a plurality of drug candidates in solution are separated based on affinity, a method is provided comprising introducing a solid-phase device having binding affinity for a selected protein into the solution, binding at least one of the plurality of drug candidates to the solid-phase device as a selected drug candidate, washing the solid-phase device and selected drug candidate to separate unbound material, sampling the selected drug candidate in capture fluid flowing through a sampling region of an open port sampling interface and directing the sampled selected drug candidate and capture fluid to an ionization source.

In a system for affinity selection by mass spectrometry, wherein a plurality of drug candidates in solution are separated based on affinity, a method is provided comprising introducing a solid-phase device having binding affinity for a selected protein into the solution, binding at least one of the plurality of drug candidates to the solid-phase device as a selected drug candidate, washing the solid-phase device and selected drug candidate to separate unbound material, sampling the selected drug candidate in capture fluid flowing through a sampling region of an open port sampling interface and directing the sampled selected drug candidate and capture fluid to an ionization source.

An apparatus comprising an ion selecting device; an individual ion counter device; and an interface device integral with the ion selecting device and downstream of an ion separating chamber of the ion selecting device. The interface device comprises a tagging particle generator and a tagging chamber. Sample gas containing ions of a selected mobility enters the tagging chamber from the ion selecting device and is exposed to uncharged neutral tagging particles from the tagging particle generator. The ions collide with the tagging particles to form a mixture of tagged ions and uncharged neutral tagging particles which is then separated in a tagged ions separator forming part of the individual ion counting device before the separated tagged ions are counted.

An apparatus comprising an ion selecting device; an individual ion counter device; and an interface device integral with the ion selecting device and downstream of an ion separating chamber of the ion selecting device. The interface device comprises a tagging particle generator and a tagging chamber. Sample gas containing ions of a selected mobility enters the tagging chamber from the ion selecting device and is exposed to uncharged neutral tagging particles from the tagging particle generator. The ions collide with the tagging particles to form a mixture of tagged ions and uncharged neutral tagging particles which is then separated in a tagged ions separator forming part of the individual ion counting device before the separated tagged ions are counted.

An ion mobility filter is disclosed. The present invention relates to but not exclusively a field asymmetric ion spectrometry filter. For example, we describe an ion filter for filtering ions in a gas sample. The ion filter is comprised of a plurality of electrodes, a first ion channel, and a second ion channel. The first ion channel filters ions from a target chemical in the gas sample, defines a gap between a first pair of electrodes in the plurality of electrodes, and has a first ion channel gap width. The second ion channel filters ions from the target chemical in the gas sample, defines a gap between a second pair of electrodes in the plurality of electrodes, and has a second ion channel gap width. The first ion channel gap width is greater than the second ion channel gap width.

An ion mobility filter is disclosed. The present invention relates to but not exclusively a field asymmetric ion spectrometry filter. For example, we describe an ion filter for filtering ions in a gas sample. The ion filter is comprised of a plurality of electrodes, a first ion channel, and a second ion channel. The first ion channel filters ions from a target chemical in the gas sample, defines a gap between a first pair of electrodes in the plurality of electrodes, and has a first ion channel gap width. The second ion channel filters ions from the target chemical in the gas sample, defines a gap between a second pair of electrodes in the plurality of electrodes, and has a second ion channel gap width. The first ion channel gap width is greater than the second ion channel gap width.