Abstract:
A method of detecting one or more compounds, chemicals or contaminants in a substrate by mass spectrometry is disclosed. A non-living substrate is analyzed by contacting the substrate with a diathermy knife. An electric current is applied to the diathermy knife such that the diathermy knife vaporizes a portion of the substrate. The vapor is aspirated via a sampling tube pumped by a venturi pump into a vacuum chamber of a mass spectrometer. Analyte molecules are aspirated into the vacuum chamber whereupon they impact a surface of the vacuum chamber and are ionized to form analyte ions which are then mass analyzed.
Abstract:
An ion inlet for a mass spectrometer is disclosed comprising a housing having a sampling orifice and an atmospheric pressure orifice. One or more gas outlets are provided in the housing. Gas is drawn through the sampling orifice by a pump so that the gas exits via the one or more gas outlets.
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:
A collision or fragmentation cell is disclosed comprising a plurality of electrodes wherein a first RF voltage is applied to an upstream group of electrodes and a second different RF voltage is applied to a downstream group of electrodes. The radial confinement of parent ions entering the collision or fragmentation cell is optimized 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 is optimized by the second different RF voltage applied to the downstream group of electrodes.
Abstract:
A mass spectrometer is disclosed comprising an ion mobility spectrometer or separator and an ion guide arranged downstream of the ion mobility spectrometer or separator. A plurality of axial potential wells are created in the ion guide so that ions received from the ion mobility spectrometer or separator become confined in separate axial potential wells. The potential wells maintain the fidelity and/or composition of ions received from the ion mobility spectrometer or separator. The potential wells are translated along the length of the ion guide.
Abstract:
An ion guide or mass analyser is disclosed comprising a plurality of electrodes having apertures through which ions are transmitted in use. A pseudo-potential barrier is created at the exit of the ion guide or mass analyser. The amplitude or depth of the pseudo-potential barrier is inversely proportional to the mass to charge ratio of an ion. One or more transient DC voltages are applied to the electrodes of the ion guide or mass analyser in order to urge ions along the length of the ion guides or mass analyser. The amplitude of the transient DC voltage applied to the electrode may be increased with time so that ions are caused to be emitted from the ion guide or mass analyser in reverse order of their mass to charge ratio.
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 wherein an ion signal is split into a first and second signal. The first and second signals are multiplied by different gains and are digitised. Arrival time and intensity pairs are calculated for both digitised signals and the resulting time and intensity pairs are combined to form a high dynamic range spectrum. The spectrum is then combined with other corresponding spectra to form a summed spectrum.
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 quadrupole rod set ion guide or mass filter device. Broadband frequency-signals (13, 14, 15) having a plurality of frequency notches (16a; 16b; 16c) are applied sequentially to the rods of the quadrupole rod set. The notched broadband frequency signals (16a, 16b, 16c) cause undesired ions to be resonantly or parametrically ejected from the ion guide. The resulting ion signals are deconvoluted to provide a mass spectrum.