Thermo Fisher Scientific (bremen) Gmbh

Wisconsin Alumni Research Foundation

Amelia Corinne Peterson

Alexander Alekseevich Makarov

Jan-Peter Hauschild

Dirk Nolting

Joshua J Coon

Alexander Kholomeev

Michael S Westphall

Oliver Lange

Timothy James Donohue

Denis Chernyshev

Aivaras Venckus

Rachelle A S Lemke

Erik Couzijn

Trapping ions in an ion trapping assembly is described. In one aspect, this is implemented by introducing ions into the ion trapping assembly, applying a first RF trapping amplitude to the ion trapping assembly so as to trap introduced ions which have m/z ratios within a first range of m/z ratios, and cooling the trapped ions. In some aspects, also performed is reducing the RF trapping amplitude from the first RF trapping amplitude to a second, lower, RF trapping amplitude so as to reduce the low mass cut-off of the ion trapping assembly and trapping, at the second, lower RF trapping amplitude, introduced ions having m/z ratios within a second range of m/z ratios. A lower mass limit of the second range of m/z ratios is below the low mass cut-off of the ion trapping assembly when the first RF trapping amplitude is applied.

Ion trapping scheme with improved mass range

A cleaning device for cleaning electrodes of an ion optical multipole device comprises at least one substantially longitudinal cleaning section, at least one handling section extending axially from the at least one cleaning section and at least one direction section extending axially from the at least one cleaning section. The at least one cleaning section has a larger cross section than the at least one handling section. The at least one direction section is capable of allowing a longitudinal movement of the cleaning device in a first axial direction and resisting a longitudinal movement of the cleaning device in a second, opposite axial direction.

Longitudinal tool for cleaning ion optic multipole devices

A method for controlling the filling of an ion trap with a predetermined quantity of ions. The method comprises generating an ion current by transmitting ions along an ion path to an ion trap, such that ions are accumulated in the ion trap over a transmission time period, wherein the magnitude of the ion current varies in time. The method further comprises detecting at an ion detector at least some ions from the source of ions during a plurality of distinct sampling time intervals interspersed within the transmission time period, and setting the duration of the transmission time period based on the detection of ions at the ion detector. The time difference between the start of a sampling time interval and the start of an immediately subsequent sampling time interval is less than a timescale for variation of the magnitude of the ion current. A controller for controlling the filling of an ion trap with a predetermined quantity of ions and a mass spectrometer comprising the controller is also described.

Charge detection for ION current control

A method of operating a mass spectrometer, comprising: generating ions from a sample; mass filtering the ions using a quadrupole mass filter having a set of selection parameters to transmit ions within at least one selected range of mass-to-charge ratios narrower than an initial range, wherein the quadrupole comprises four parallel elongate electrodes arranged in opposing pairs to which are applied RF and DC, wherein an attractive DC voltage is applied to one pair of opposing electrodes and a repulsive DC voltage is applied to the other pair; mass analysing or detecting the ions transmitted by the quadrupole mass filter; repeating the steps of generating ions, mass filtering and mass analysing or detecting multiple times; switching a configuration of the pairs of opposing electrodes to which the attractive DC voltage and the repulsive DC voltage are applied multiple times over the course of repeating the steps so that over long term operation the build-up of contamination on each pair of opposing electrodes is substantially equal; and determining mass filtering steps for which quantitative accuracy should be maintained between them and for the determined mass filtering steps maintaining the same configuration of the pairs of opposing electrodes to which the attractive DC voltage and the repulsive DC voltage are applied. The width of the selected mass range may change by not more than 10% when the ion transmission efficiency mass filter falls by 50% or more due to the build-up of contamination on the electrodes.

Mass spectrometer having improved quadrupole robustness

Disclosed herein is an ion supply system, having an ion source emitting ions into a fore vacuum chamber, an ion transport device having stacked electrodes arranged in the fore vacuum chamber, a control system supplying an oscillatory voltage to the electrodes of the ion transport device and a vacuum chamber, arranged downstream from the ion transport device. A vacuum gauge is arranged in the vacuum chamber. The pressure signal of the vacuum gauge is supplied to the control system supplying the oscillatory voltage to electrodes of the ion transport device. The control system adjusts the amplitude of the oscillatory voltage in accordance with the pressure signal.

Ion supply system and method to control an ion supply system

Enzymes for producing non-straight-chain fatty acids, microorganisms comprising the enzymes, and in vivo and in vitro uses of the enzymes. Provided are enzymes capable of producing various non-straight-chain fatty acids, including branched-chain fatty acids, cyclic fatty acids, and furan-containing fatty acids. The enzymes include RSP2144, RSP1091, and RSP1090 fromand homologs thereof. The enzymes can be purified to produce non-straight-chain fatty acids in vitro or expressed in microorganisms to produce non-straight-chain fatty acids in vivo. The microorganisms can be fine-tuned to produce a specific type of non-straight-chain fatty acid by expressing, overexpressing, or deleting the enzymes in various combinations.

Growing community of inventors

Bremen, Germany

Amelia Corinne Peterson