MS/MS MASS SPECTROMETER
First Claim
1. An MS/MS mass spectrometer including:
- a first mass separator for selecting, as a precursor ion, an ion having a specific mass from among various kinds of ions;
a collision cell, containing an ion guide for transporting ions by a radio-frequency electric field while converging those ions, for making the precursor ion collide with a predetermined gas to dissociate the precursor ion by collision-induced dissociation; and
a second mass separator for selecting an ion having a specific mass from among various kinds of product ions generated by the dissociation of the precursor ion, the first mass separator, the collision cell and the second mass separator being linearly arranged, and the MS/MS mass spectrometer is characterized by comprising;
a) lens electrodes respectively provided at an entrance end and an exit end of the collision cell;
b) a voltage-applying means for applying a DC voltage to one or both of the entrance lens electrode and the exit lens electrode; and
c) a control means for controlling the voltage-applying means so that a pulsed DC voltage for either pulling or repelling the ions within the collision cell is applied to the aforementioned one or both of the lens electrodes at a predetermined timing in order to remove the ions from the collision cell.
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Accused Products
Abstract
During a halt period of time when the introduction of ions is temporarily discontinued to change an objective ion to be selected by a first mass separator in the previous stage, a pulsed voltage having a polarity opposite to that of the ions remaining in a collision cell (4) is applied to an entrance lens electrode (42) and exit lens electrode (44). The ions are pulled by the DC electric field created by this voltage, to be neutralized and removed by colliding with the lens electrodes (42, 44). Thus, the residual ions, which may cause a crosstalk, can be quickly removed from the inner space of the collision cell (4) without contaminating an ion guide (5) to which a radio-frequency is applied. Since no radio-frequency voltage is applied to the lens electrodes (42, 44), the circuit for applying the pulsed voltage can have a simple configuration. Thus, the cost increase is suppressed.
18 Citations
8 Claims
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1. An MS/MS mass spectrometer including:
- a first mass separator for selecting, as a precursor ion, an ion having a specific mass from among various kinds of ions;
a collision cell, containing an ion guide for transporting ions by a radio-frequency electric field while converging those ions, for making the precursor ion collide with a predetermined gas to dissociate the precursor ion by collision-induced dissociation; and
a second mass separator for selecting an ion having a specific mass from among various kinds of product ions generated by the dissociation of the precursor ion, the first mass separator, the collision cell and the second mass separator being linearly arranged, and the MS/MS mass spectrometer is characterized by comprising;a) lens electrodes respectively provided at an entrance end and an exit end of the collision cell; b) a voltage-applying means for applying a DC voltage to one or both of the entrance lens electrode and the exit lens electrode; and c) a control means for controlling the voltage-applying means so that a pulsed DC voltage for either pulling or repelling the ions within the collision cell is applied to the aforementioned one or both of the lens electrodes at a predetermined timing in order to remove the ions from the collision cell. - View Dependent Claims (2, 3, 4, 5, 6, 8)
- a first mass separator for selecting, as a precursor ion, an ion having a specific mass from among various kinds of ions;
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7. (canceled)
Specification