摘要:
An ion guide or mass analyser (2) is disclosed comprising a plurality of electrodes (2a) 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 (2). 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 (4) are applied to the electrodes (2a) of the ion guide or mass analyser (2) in order to urge ions along the length of the ion guides or mass analyser (2). The amplitude of the transient DC voltage (4) applied to the electrode (2a) may be increased with time so that ions are caused to be emitted from the ion guide or mass analyser (2) in reverse order of their mass to charge ratio.
摘要:
A mass spectrometer is disclosed comprising an ion beam attenuator which attenuates an ion beam repeatedly switching between a zero transmission mode of operation during a time period ΔT1 and a non-zero transmission mode of operation during a time period ΔT2. The degree of attenuation of the ion beam can be varied by varying the mark space ratio ΔT2/ΔT1. The ion beam attenuator may release ions in packets or pulses but the packets or pulses of ions may be converted into a continuous ion beam by a relatively high pressure ion guide or gas collision cell arranged downstream of the ion beam attenuator.
摘要:
A Time of Flight mass analyser is disclosed comprising one or more devices arranged and adapted to correct for tilt in an isochronous plane of ions and to adjust the isochronous plane of the ions so as to be parallel with the plane of detection in an ion detector.
摘要:
A mass spectrometer is disclosed comprising an ion mobility spectrometer or separator (4) and an ion guide (6) arranged downstream of the ion mobility spectrometer or separator (4). A plurality of axial potential wells are created in the ion guide (6) so that ions received from the ion mobility spectrometer or separator (4) 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 (4). The potential wells are translated along the length of the ion guide (6).
摘要:
A mass spectrometer is disclosed comprising an ion mobility spectrometer in combination with a quadrupole mass filter which is scanned in synchronisation with the pulsing of ions into the ion mobility spectrometer thereby enabling ions having a particular charge state to be preferentially transmitted. Another embodiment replaces the quadrupole mass filter with an axial time of flight mass filter and an injection electrode.
摘要:
A method of mass spectrometry is disclosed wherein ions are trapped for a period of time T within an AC or RF ion guide maintained at a pressure P wherein the product P×T is at least 1 mbar-ms. The effect of trapping the ions according to a preferred embodiment is that singly charged ions which may, for example, comprise unwanted background ions are substantially lost from the trap whereas multiply charged analyte ions are maintained within the ion trap and can then be released for subsequent mass analysis.