1144 results about "Mass" patented technology

A system (20) and method are disclosed for the self-calibrating, on-line determination of size distribution f(x) and volume fraction φ of a number of particles (P) dispersed in a medium (M) by detecting one or more propagation characteristics of multiply scattered light from the particles (P). The multiply scattered light is re-emitted in response to exposure to a light source (21) configured to provide light at selected wavelengths. The determination includes calculating the isotropic scattering and absorption coefficients for the particles (P) by comparing the incident and detected light to determine a measurement corresponding to the propagation time through the scattering medium (M), and iteratively estimating the size distribution f(x) and volume fraction φ as a function of the coefficients for each of the wavelengths. An estimation approach based on an expected form of the distribution and the mass of the particles is also disclosed. Furthermore, techniques to determine a particle structure factor indicative of particle-to-particle interactions which vary with particle concentration and influence light scattering at high concentrations is disclosed.

A new ionization source named Surface Activated Chemical Ionization (SACI) has been discovered and used to improve the sensitivity of the mass spectrometer. According to this invention the ionization chamber of a mass spectrometer is heated and contains a physical new surface to improve the ionization process. The analyte neutral molecules that are present in gas phase are ionized on this surface. The surface can be made of various materials and may also chemically modified so to bind different molecules. This new ionization source is able to generate ions with high molecular weight and low charge, an essential new key feature of the invention so to improve sensitivity and reduce noise. The new device can be especially used for the analysis of proteins, peptides and other macromolecules. The new invention overcomes some of the well known and critical limitations of the Electrospray (ESI) and Matrix Assisted Laser Desorption Ionization (MALDI) mass spectrometric techniques.

A mass spectrometer is disclosed wherein a relatively energetic pulse of ions having a relatively narrow spread of mass to charge ratios are ejected from a quadrupole ion trap and received in an ion trap upstream of a Time of Flight mass analyser. The ions are collisionally cooled within the ion trap and are pulsed out of the ion trap and into an extraction region of the Time of Flight mass analyser without substantially exciting the ions. This enables improved operation with the Time of Flight mass analyser. According to another embodiment, parent ions are fragmented and the resulting fragment ions are stored in two ion traps having different low mass cut-offs. The trapping system enables MS/MS experiments to be performed with a very high duty cycle.

A multi-reflection time-of-flight mass spectrometer (MR-TOFMS) and an analysis method are disclosed. The flight paths of the ions are folded along a trajectory through electrostatic mirrors. Longer flight paths provide higher resolution while maintaining a modest instrument size.

A mass spectrometer and a method of mass spectrometry are disclosed wherein periodic background noise is effectively filtered out from the mass spectral data. An overall mass window is superimposed upon the mass spectral data. The overall mass window preferably comprises 21 nominal mass windows each preferably having a width of 1.0005 amu. Each nominal mass window preferably comprises 20 channels. An intensity distribution relating to all the first channels of the 21 nominal mass windows is determined. An intensity quantile is determined from the intensity distribution. The intensity quantile is taken to represent the background intensity in the first channel of the central nominal mass window. This process is repeated for the other channels so that the background intensity across the whole of the central nominal mass window is estimated and then subtracted from the raw mass spectral data comprising the central nominal mass window. The overall mass window is then preferably advanced approximately 1 amu and the process is repeated multiple times.

The invention belongs to the quality analysis technology field and in particular relates to a method of using a plurality of ion traps for the tandem mass spectrometric analysis, including that a high frequency capturing electric field based on a quadrupole field is produced in the first ion trap for capturing ions with various mass-to-charge ratios. A dipolar excitation alternating electric field with certain frequency along the direction of a straight line for connecting the center of the first ion trap center with the center of a second ion trap center is produced in the first ion trap. Thus, the ions with a mass-to-charge ratio oscillate along the direction to reach to the large amplitude under the resonance excitation. Furthermore, a discharged pulse electric field generates in a specific phase of the first ion trap. The ions reaching to the large moving amplitude are discharged and enter the second ion trap. And the ions with other mass-to-charge ratios are still left in the first ion trap. Through a deceleration field added in the second ion trap or the gas collision, the entering ions or byproduct ions are captured and the researching analysis is further made in the second ion trap.

The invention discloses a method and system for increasing judgment accuracy of monoisotopic peaks. The method comprises the following steps: according to selected tandem mass spectrums, determining candidate isotopic peak clusters; according to the similarity and the strength ratio of the chromatographic outflow curves of the candidate isotopic peak clusters, determining the start and stop of the isotopic peak clusters; according to the start and stop of the isotopic peak clusters, determining the quality of the monoisotopic peaks; and judging whether the monoisotopic peaks of the tandem mass spectrums are not determined or not, if yes, returning and selecting a new tandem mass spectrum to determine a candidate isotopic peak cluster, and if not, ending.

A mass spectrometer is disclosed wherein a z-lens upstream of an orthogonal acceleration Time of Flight mass analyser is repeatedly switched between a first mode wherein ions are transmitted to the mass analyser for subsequent mass analysis with a relatively high transmission and a second mode wherein ions are transmitted with a relatively low transmission. If it is determined that mass spectral data obtained when the mass analyser is in the first mode is suffering from saturation, then suitably scaled mass spectral data obtained when the mass analyser is in the second mode is used instead. If the saturation is severe then the mass spectral data obtained in the first mode may be replaced in its entirety with mass spectral data obtained in the second mode.

The invention relates to a mass spectrometric mixture analysis to determine both simple mass spectra of the substances as well as more detailed information about structures and other characteristics of the substances. The invention consists in temporally separating the substance mixture in a separating device, splitting the eluating flow of substances into at least two partial flows and measuring the substances in the different partial flows by mass spectrometry. A direct measurement provides a series of spectra whose evaluation is used for optimal control of the time at which a spectrum of another, delayed partial flow is acquired and the type of this measurement procedure. The substances of the delayed partial flows or their ions can thereby be chemically or physically modified in a variety of ways in order to provide the molecular weight as well as more detailed information.

A mass analysis of a standard sample having a known mass-to-charge ratio is carried out by performing a mass scan at a first-stage quadrupole (13) over a predetermined mass range, under the condition that a collision induced dissociation (CID) gas is introduced into a collision cell (14) and a voltage applied to a third-stage quadrupole (17) is set so that no substantial mass separation occurs in this quadrupole. Various kinds of product ions originating from a precursor ion selected by the first-stage quadrupole (13) arrive at and are detected by a detector (18) without being mass separated. Accordingly, based on the detection data, a data processor (25) can obtain a relationship between the voltage applied to the first-stage quadrupole (13) and the mass-to-charge ratio of the selected ions, with a time delay in the collision cell (14) reflected in that relationship. This relationship is stored in a calibration data memory (26), to be utilized in a neutral loss scan measurement or the like. By using this relationship, a mass shift due to the time delay in the collision cell (14) can be cancelled, so that the product ions can be detected with high sensitivity over the entire mass range. Furthermore, a mass spectrum having an accurate mass axis can be created.

A method of tandem mass spectrometry is disclosed. A quasi-continuous stream of ions from an ion source (20) and having a relatively broad range of mass to charge ratio ions is segmented temporally into a plurality of segments. Each segment is subjected to an independently selected degree of fragmentation, so that, for example, some segments of the broad mass range are fragmented whilst others are not. The resultant ion population, containing both precursor and fragment ions, is analyzed in a single acquisition cycle using a high resolution mass analyser (150). The technique allows the analysis of the initial ion population to be optimized for analytical limitations.