A time-of-flight, TOF, mass spectrometer, MS, comprising: an ion source for supplying a group of ions, including a first ion having a first mass-to-charge ratio m.sub.1/z.sub.1, a second ion having a second mass-to-charge ratio m.sub.2/z.sub.2 and a third ion having a third mass-to-charge ratio m.sub.3/z.sub.3 wherein m.sub.3/z.sub.3>m.sub.2/z.sub.2>at a time t.sub.0; a first set of electrodes, including a first electrode, and a second set of electrodes, including a first electrode and an Nth electrode, wherein the first set of electrodes and the second set of electrodes are mutually spaced apart by a gap therebetween; an ion detector for detecting the ions; a set of power supplies, including a first power supply, electrically coupled to the first set of electrodes and to the second set of electrodes; and a controller configured to control the set of power supplies to apply respective potentials to the first set of electrodes and the second set of electrodes; wherein the controller is configured to control the set of power supplies to: provide a first substantially field-free region between the ion source and the first set of electrodes to allow the group of ions to expand theretowards and/or therein, at the time t0; apply an extraction potential V.sub.extraction to the first set of electrodes at a time t.sub.extraction>t.sub.0, to extract the expanded group of ions, while maintaining a second substantially field-free region beyond the first set of electrodes, in the gap between the first set of electrodes and the second set of electrodes; and optionally, change an acceleration potential V.sub.acceleration applied to the second set of electrodes during a time period Δt=t.sub.off−t.sub.on, wherein ton>t.sub.extraction, to vary acceleration of the extracted group of ions based, at least in part, on respective mass-to-charge ratios.

A method of mass spectrometry for analyzing a sample within a mass range of interest includes the steps: ionizing the sample to produce a plurality of precursor ions; performing an MS1 scan of the precursor ions comprising mass analyzing the precursor ions across the mass range of interest, to obtain an MS1 mass spectrum of the precursor ions; determining ion intensity values within the MS1 mass spectrum; selecting precursor mass segments within the mass range of interest, and for each precursor mass segment: fragmenting the precursor ions within that precursor mass segment; and performing an MS2 scan of the fragmented ions by: controlling an amount of fragmented ions for that precursor mass segment, based on an intensity value for that precursor mass segment derived from the MS1 spectrum; and mass analyzing the amount of fragmented ions.

An ion mobility spectrometry apparatus and method wherein ions are selected using an AC gate, then separated along a drift axis while providing a drift gas flow in a direction that is substantially neither in the direction of the drift axis nor opposite to the drift axis.

Systems and methods are used to analyze a sample using variable mass selection window widths. A tandem mass spectrometer is instructed to perform at least two fragmentation scans of a sample with different mass selection window widths using a processor. The tandem mass spectrometer includes a mass analyzer that allows variable mass selection window widths. The selection of the different mass selection window widths can be based on one or more properties of sample compounds. The properties may include a sample compound molecular weight distribution that is calculated from a molecular weight distribution of expected compounds or is determined from a list of molecular weights for one or more known compounds. The tandem mass spectrometer can also be instructed to perform an analysis of the sample before instructing the tandem mass spectrometer to perform the at least two fragmentation scans of the sample.

A method of data-independent mass spectrometric analysis of compounds of a compound class of interest comprises: determining or retrieving a distribution, over a mass-to-charge (m/z) ratio range of interest, of a number of primary ion species of members of said compound class having m/z ratios within each respective one of a plurality of m/z sub-ranges of the m/z ratio range of interest; defining m/z positions of a set consisting of a number, n.sub.sb, of finite-width bins, within the m/z ratio range of interest, the set of bins excluding m/z sub-ranges within the m/z ratio range of interest that encompass fewer than a threshold number, t.sub.sb, of the primary ion species, wherein the defining based on the determined or received distribution; and performing a plurality of tandem mass analyses, each tandem mass analysis pertaining to primary ion species within a respective one of the defined bins.

The invention generally relates to systems and methods for performing multiple precursor, neutral loss and product ion scans in a single ion trap. In certain aspects, the invention provides systems including a mass spectrometer having a single ion trap, and a central processing unit (CPU), and storage coupled to the CPU for storing instructions that when executed by the CPU cause the system to apply at least one of the following ion scans to a single ion population in the single ion trap: multiple precursor ion scans, a plurality of segmented neutral loss scans, or multiple simultaneous neutral loss scans.

A method is disclosed comprising providing a biological sample on a swab, directing a spray of charged droplets onto a surface of the swab in order to generate a plurality of analyte ions, and analysing the analyte ions.

Provided herein, among other things, is a method of ionizing a first stream of liquid by an electrospray ion source having a nebulizer, wherein the first stream of liquid may comprise an analyte. In some embodiments, the method may comprise: a) providing the first stream of liquid to the nebulizer; b) adding a second stream of liquid to the first stream of liquid, wherein the second stream of liquid comprises a co-solvent that has a relatively high boiling point and an enhancement solvent that a relatively high boiling; and c) nebulizing and ionizing the resulting liquid.

A method for measuring a sample comprising silicon by mass spectrometry is implemented from an inductively coupled plasma-tandem mass spectrometer, or ICP-MS/MS. The measurement method comprises a step of measuring by mass spectrometry by a reactive gas. The reactive gas comprising nitrous oxide.

A method is disclosed comprising providing a biological sample on a swab, directing a spray of charged droplets onto a surface of the swab in order to generate a plurality of analyte ions, and analysing the analyte ions.