604results about "Specific reaction combinations" patented technology

A novel curved collision cell for a mass spectrometer is described. The collision cell includes a straight section having a length that is selected to cause a precursor ion entering the straight section to lose a desired amount of kinetic energy such that when the precursor ion enters the curved section of the collision cell the precursor ion will tend to neither escape nor contact the collision cell, and thereby tending to survive its passage within the curved portion.

Systems and methods are used to store an electronic record of all product ion spectra of all detectable compounds of a sample. A plurality of product ion scans are performed on a tandem mass spectrometer one or more times in a single sample analysis across a mass range using a plurality of mass selection windows. All sample product ion spectra of all detectable compounds for each mass selection window are produced. All sample product ion spectra for each mass selection window are received from the tandem mass spectrometer using a processor. All sample product ion spectra for each mass selection window are stored as an electronic record of all detectable compounds of the sample using the processor. The electronic record is used to characterize compounds known at the time the electronic record is stored or to characterize compounds that became known after the electronic record was stored.

This invention provides methods, devices and device components for preparing ions from liquid samples containing chemical species and methods and devices for analyzing chemical species in liquid samples. The present invention provides an ion source for generating analyte ions having a selected charge state distribution, such as a reduced charged state distribution, that may be effectively interfaced with a variety of charged particle analyzers, including virtually any type of mass spectrometer.

Systems and methods of generating ions at atmospheric pressure are presented. These systems and methods include spatially dependent analysis of a sample using an effusive ionization source. Systems and methods of isolating samples at atmospheric pressure are presented. These systems and methods include using a barrier to prevent metastables or electrons from an effusive ion source from reaching a sample unless the sample is in an analysis position. Systems and methods of using metastables in collisionally induced dissociation are presented.

A dual ion trap mass analyzer includes adjacently positioned first and second two-dimensional ion traps respectively maintained at relatively high and low pressures. Functions favoring high pressure (cooling and fragmentation) may be performed in the first trap, and functions favoring low pressure (isolation and analytical scanning) may be performed in the second trap. Ions may be transferred between the first and second trap through a plate lens having a small aperture that presents a pumping restriction and allows different pressures to be maintained in the two traps. The differential-pressure environment of the dual ion trap mass analyzer facilitates the use of high-resolution analytical scan modes without sacrificing ion capture and fragmentation efficiencies.

Improved ion focusing for an ion mobility drift cell allows for improved throughput for subsequent detection such as mass detection. Improved focusing is realized by the use of alternating regions of high and low electric fields in the ion mobility drift cell.

A method of calibrating ion collision energy used in a mass spectrometer, comprises: (a) obtaining fragment ion yield data for each of a plurality of precursor ion populations having respective mass-to-charge ratios at each of a plurality of settings of a fragmentation-energy-related variable; (b) locating, for each mass-to-charge ratio, reference values of the fragmentation-energy-related variable, each reference value corresponding to a respective reference feature of the ion yield data at the mass-to-charge ratio; (c) determining, from the plurality of locating steps, the variation, with mass-to-charge-ratio, of each of the reference values of the fragmentation-energy-related variable; (d) associating each of the reference values of the fragmentation-energy related variable with respective reference values of a dimensionless useable-fragmentation-energy variable; and (e) storing parameters describing the variation of each of the reference values of the fragmentation-energy-related variable with mass-to-charge ratio, wherein the parameters comprise coefficients of at least one non-linear equation.

Methods for fragmenting ions in an ion trap are described. These methods involve a) selecting parent ions for fragmentation; b) retaining the parent ions within the ion trap for a retention time interval, the ion trap having an operating pressure of less than about 1×10-4 Torr; c) providing a RF trapping voltage to the ion trap to provide a Mathieu stability parameter q at an excitement level during an excitement time interval within the retention time interval; d) providing a resonant excitation voltage to the ion trap during the excitement time interval to excite and fragment the parent ions; e) providing a non-steady-state pressure increase of at least 10% of the operating pressure within the ion trap by delivering a neutral gas into the ion trap for at least a portion of the retention time interval to raise the pressure in the ion trap to a varying first elevated-pressure in the range between about 6×10-5 Torr to about 5×10-4 Torr for a first elevated-pressure duration; and f within the retention time interval and after the excitement time interval, terminating the resonant excitation voltage and changing the RF trapping voltage applied to the ion trap to reduce the Mathieu stability parameter q to a hold level less than the excitement level to retain fragments of the parent ions within the ion trap. The excitation time interval and the first elevated-pressure duration substantially overlap in time.

A mass spectrometric method for determining the position of unsaturation in a compound is disclosed.

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 means and method are disclosed whereby ions from an ion source can be selected and transferred to a time-of-flight mass analyzer via an arrangement of multipoles in such a way that fragmented ions may be generated by collision-induced dissociation or surface-induced dissociation. First, ions from the source are collisionally cooled by a first multipole. Second, the m / z range of the ions is then selected by a second multipole (preferably a quadrupole). Third, the selected ions are allowed to collide with a "collision surface" capable of producing fragment ions. Fourth, these fragment ions are collisionally cooled in a third multipole and delivered into a TOF mass analyzer for subsequent analysis of the fragmented ions.

A mass spectrometer is provided that is configurable for operation in both a Kinetic Energy Discrimination (KED) mode and a dynamic reaction cell (DRC) mode. To operate in the KED mode, a collision cell can be filled with a quantity of the inert gas, and an energy barrier can be formed between the collision cell and a downstream mass analyzer. To operate instead in the DRC mode, the collision cell can be filled with a quantity of gas that is reactive with the interferer ions.

A mass spectrometer is disclosed comprising a collision cell wherein ions having substantially different mass to charge ratios are arranged to be transmitted through at least a portion of the collision cell at substantially the same time and with substantially the same velocity preferably by means of one or more transient DC voltages or one or more transient DC voltage waveforms which are applied to the electrodes forming the collision cell so that ions are urged through the collision cell at a constant controlled velocity. By appropriate setting of the velocity of the DC voltage or DC voltage waveform passing along the length of the collision cell an efficient collision cell is provided which is able to fragment ions having considerably different mass to charge ratio at substantially the same time in an optimal manner.

In the field of mass spectrometry, a method of obtaining a mass spectrum enriched with fragment ions while retaining the precursor ion. The technique includes varying the collision energy experienced by the precursor ion such that a range of fragmentations occur. Related methods are also disclosed for obtaining MS, MS2, MS3 and MSn spectra which are enriched with fragment ions.

Systems and methods are used to store an electronic record of all product ion spectra of all detectable compounds of a sample. A plurality of product ion scans are performed on a tandem mass spectrometer one or more times in a single sample analysis across a mass range using a plurality of mass selection windows. All sample product ion spectra of all detectable compounds for each mass selection window are produced. All sample product ion spectra for each mass selection window are received from the tandem mass spectrometer using a processor. All sample product ion spectra for each mass selection window are stored as an electronic record of all detectable compounds of the sample using the processor. The electronic record is used to characterize compounds known at the time the electronic record is stored or to characterize compounds that became known after the electronic record was stored.