Abstract:
An ion source is disclosed wherein a sample is introduced into the sample chamber (1) of the ion source in the gas phase via a sample introduction capillary tube (2). The sample is directed onto a heated surface (6) coated with an oxidising reagent such as copper oxide. Carbon in the sample is oxidised to form carbon dioxide. The resulting carbon dioxide molecules are then ionised by electron impact ionisation with an electron beam (3) and the resulting ions are passed to a mass analyser for mass analysis.
Abstract:
A mass spectrometer is disclosed comprising an ion mobility spectrometer (8) and an ion gate (9). A collision cell (10) is arranged downstream of the ion gate (9). The operation of the ion mobility spectrometer (8) and the ion gate (9) are synchronised so that only ions having a particular mass to charge ratio and a desired charge state are onwardly transmitted to the collision cell (10).
Abstract:
A mass spectrometer is disclosed comprising a 2D or 3D ion trap. The 2D ion trap comprises a quadrupole rod set ion trap wherein a slot is provided in each of the rods 1 to allow ions to be ejected radially from the ion trap. The 3D ion trap comprises a central ring electrode which is radially segmented and wherein a slot is provided in each radial segment to allow ions to be ejected radially from the ion trap. Ions having different mass to charge ratios and/or opposite polarities may be simultaneously ejected from the ion trap via different exit pathways.
Abstract:
A collision or fragmentation cell (4) is disclosed comprising a plurality of electrodes wherein a first RF voltage (7a) is applied to an upstream group of electrodes and a second different RF voltage (7b) is applied to a downstream group of electrodes. The radial confinement of parent ions entering the collision or fragmentation cell (4) is optimised by the first RF voltage applied to the upstream group of electrodes and the radial confinement of daughter or fragment ions produced within the collision or fragmentation cell (4) is optimised by the second different RF voltage applied to the downstream group of electrodes.
Abstract:
A mass spectrometer is disclosed comprising a Time of Flight mass analyser comprising an ion detector comprising an Analogue to Digital Converter. Signals from the Analogue to Digital Converter are digitised and the arrival time and intensity of ions are determined. The arrival time T 0 and intensity S 0 of each ion arrival event is converted into two separate intensities S (n) ,S (n+i) which are stored in neighbouring time bins T (n) , T (n+1) .
Abstract:
A Time of Flight mass analyser is disclosed comprising an ion detector comprising an Analogue to Digital Converter. Output signals from the ion detector are digitised and the arrival times and intensity values relating to ion arrival events are determined. If the determined arrival times from two signals fall within the same time window then the arrival times are added together in a weighted manner and the intensity values are combined.
Abstract:
An ion guide (7a) is disclosed comprising one or more layers of intermediate planar, plate or mesh electrodes (2). A first array of first electrodes (8a-8e) is provided on an upper surface and a second array of second electrodes (9a-9e) is arranged on a lower surface. An ion guiding region is formed within the ion guide (7a). One or more transient DC voltages or potentials are preferably applied to the first and second array of second electrodes (8a-8e, 9a-9e) in order to urge, propel, force or accelerate ions through or along the ion guide (7a).
Abstract:
An electrostatic analyzer (1) for dispersing a beam of charged particles (10) according to their energy comprises two groups (2, 3) of spaced-apart linear electrodes (4, 8, 9, 20) respectively disposed above and below the charged particle beam. The potentials of the electrodes (4, 8, 9, 20) in each group progressively increase from one to the next, thereby providing an electrostatic field in a central plane (7) between the groups which is capable of deflecting the charged particles along different curved trajectories (11, 12) according to their energies. Various mass spectrometers incorporating such an analyzer are also disclosed.
Abstract:
A method of mass spectrometry is disclosed wherein an Electron Capture Dissociation, Electron Transfer Dissociation or Surface Induced Dissociation fragmentation device is repeatedly switched between a high fragmentation or reaction mode and a low fragmentation or reaction mode. Parent ions from a first sample are passed through the device and parent ion mass spectra and fragmentation ion mass spectra are obtained. Parent ions from a second sample are then passed through the device and a second set of parent ion mass spectra and fragmentation ion mass spectra are obtained. The mass spectra are then compared and if either certain parent ions or certain fragmentation ions in the two samples are expressed differently then further analysis is performed to seek to identify the ions which are expressed differently in the two different samples.
Abstract:
A mass spectrometer is disclosed comprising an ion mobility spectrometer or separator (6) arranged upstream of a collision or fragmentation cell (8). Ions are separated according to their ion mobility within the ion mobility spectrometer or separator (6). The kinetic energy of the ions exiting the ion mobility spectrometer or separator (6) is increased substantially linearly with time in order to optimise the fragmentation energy of ions as they enter the collision or fragmentation cell (8). During the time that the potential of the ion mobility spectrometer or separator (6) is being varied, the potential of ion-optical components upstream of the ion mobility spectrometer or separator (6) such as an ion source (1), ion guide (2), quadrupole mass filter (3), optional second collision or fragmentation cell (4) and an ion trapping device (5) are kept constant.