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.

Provided are synthetic dendrimer calibrants for mass spectrometry. The calibrants are distinguished by their relative case and rapidity of synthesis, comparatively low cost, long shelf life, high purity, and amenability to batch synthesis as mixtures. The latter characteristic enables parallel preparation of higher molecular weight compounds displaying useful distributions of discrete molecular weights, thereby providing multi-point mass spectrometry calibration standards. Methods of making, tuning and using said calibrants are provided.

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.

Systems and methods are provided for analyzing a sample using overlapping measured mass selection window widths. A mass range of a sample is divided into two or more target mass selection window widths using a processor. The two or more target widths can have the same width or variable widths. A tandem mass spectrometer is instructed to perform two or more fragmentation scans across the mass range using the processor. Each fragmentation scan of the two or more fragmentation scans includes a measured mass selection window width. The two or more measured widths of the two or more fragmentation scans can have the same width or variable widths. At least two of the two or more measured mass selection window widths overlap. The overlap in measured mass selection window widths corresponds to at least one target mass selection window width.

System for performing chemical spectroscopy on samples from the scale of nanometers to millimeters or more with a multifunctional platform combining analytical and imaging techniques including dual beam photo-thermal spectroscopy with confocal microscopy, Raman spectroscopy, fluorescence detection, various vacuum analytical techniques and/or mass spectrometry. In embodiments described herein, the light beams of a dual-beam system are used for heating and sensing.

A method and system to determine mass fraction of aromatic hydrocarbons, sulfur-multi-sulfur, sulfur-nitrogen, multi-sulfur-multi-nitrogen, and nitrogen containing aromatic compound classes present within a petroleum sample. The invention uses total sulfur determination, total nitrogen determination, and elemental formulas determination, with the latter determined through time-of-flight mass spectrometric analysis with atmospheric pressure photo ionization and Fourier-transform ion-cyclotron resonance mass spectrometric analysis with atmospheric pressure photo ionization.

Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally directed to ionizing a vitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. Also provided are methods to detect the presence or amount of two or more vitamin D metabolites in a single assay.

The invention relates to methods for the detailed analysis of ion mixtures from complex mixtures of organic substances in time-of-flight mass spectrometers which are equipped with a trapped ion mobility spectrometer, a quadrupole mass selector and a fragmentation cell. The invention proposes to analyze ion signals of a first mass mobility map, fragment ion spectra and the identifications of the associated substances as to whether ion mixtures not resolved according to mass and mobility, for example from isomers or isobars, are possibly present, and to subsequently measure the ion signals of interest with method parameters which allow the ion species to be measured separately by means of high mobility resolution.

Using ion mobility separation to improve a duty cycle of a mass spectrometer is described. In one aspect, a mass spectrometer can use an ion-mobility spectrometer to allow for more multiply-charged ions to transmit through than singly-charged ions. This results in a mass analyzer to perform a mass analysis with more multiply-charged ions.

A method for analyzing a sample includes identifying a plurality of precursors for analysis and grouping the precursors into two or more groups. The precursors are grouped such that for the precursors within a group the masses of ions of the precursors in the group are within a first mass range, and the number of precursors within the group is below a maximum allowable number of precursors. The method further includes generating ions from the sample; isolating precursor ions of a group; determining the mass-to-charge ratio of the precursor ions or fragments thereof; and repeating the isolating and determining steps for each group. The method also includes identifying or quantifying the presence of one or more precursors within the sample based on the presence of fragmented ions having a mass-to-charge ratio corresponding to the product ions for the one or more precursors.