Shimadzu Corporation

Shimadzu Co.

Motohide Yasuno

Ryo Fujita

Akiko Imazu

Masaru Nishiguchi

Yoshinori Arita

A spray area in which a large number of droplets of a liquid sample sprayed from a spray nozzle () is separated from the tip of a needle electrode () for corona discharge by a sufficiently large distance, with a grid electrode () facing the needle electrode () placed in between. Ring electrodes () for creating an electric field which drives primary ions that should react with the sample and generate sample-derived ions are provided within an ion chamber () between the grid electrode () and the spray area. Primary ions generated by corona discharge within the space between the needle electrode () and the grid electrode () pass through the opening of the grid electrode (), reach the spray area under the effect of the electric field, and ionize sample components. Since the droplets are prevented from adhering to the needle electrode (), the corona discharge is maintained in a stable state. The resultant primary ions are efficiently transported and used for the ionization of the sample. Therefore, no spike noise due to an unstable corona discharge occurs, so that a high-quality spectrum can be obtained.

Ion mobility spectrometer

An ion mobility analyzing apparatus includes: a drift tube having an internal space extending in a first direction; an ion chamber having an internal space extending in the first direction and connected to the drift tube; an ion gate installed at a boundary between the drift tube and the ion chamber and kept at a ground potential; an ion source supplying ions into the ion chamber; an ion detecting electrode arranged in the drift tube on a side opposite to the ion gate; a first voltage source supplying a first high voltage to the ion chamber; a second voltage source supplying a second high voltage, having an opposite polarity to that of the first high voltage, to the ion detecting electrode; and a signal transfer unit that detects a signal from the ion detecting electrode and transmits the signal to a data processing device operating with the ground potential.

Ion mobility analyzing apparatus

A spray area in which a large number of droplets of a liquid sample sprayed from a spray nozzle is separated from the tip of a needle electrode for corona discharge by a sufficiently large distance, with a grid electrode facing the needle electrode placed in between. Ring electrodes for creating an electric field which drives primary ions that should react with the sample and generate sample-derived ions are provided within an ion chamber between the grid electrode and the spray area. Primary ions generated by corona discharge within the space between the needle electrode and the grid electrode pass through the opening of the grid electrode, reach the spray area under the effect of the electric field, and ionize sample components. Since the droplets are prevented from adhering to the needle electrode, the corona discharge is maintained in a stable state.

A first shutter gate is disposed at an entrance of a drift region, and a second shutter gate is disposed on the downstream side in an ion-drifting direction. In a high-resolution measurement mode, a controller () controls voltage generators to open the second shutter gate to collect ions into a pulsed form at the first shutter gate. In this mode, the controller controls the voltage generators to open the first shutter gate to collect ions into a pulsed form at the second shutter gate. In a zoom-in measurement mode where ions within a specified range of ion mobility are measured with high resolving power, the controller controls the voltage generators to open the first shutter gate for a short period of time, and then to open the second shutter gate for a short period of time after a lapse of a predetermined time period.

A technique for improving the efficiency of injecting ions into the electrode unit of a funnel structure having high ion-transport efficiency is provided to improve the overall ion-transport efficiency. From an ionization chamberfor ionizing a sample under atmospheric pressure, ions are injected through a straight capillary pipeinto the inner space of the electrode unitof a funnel structure composed of ring electrodes in a first intermediate vacuum chamber. The space for setting the capillary pipeis formed by replacing one or more ring electrodes with C-shaped electrodes whose circumference portion is partially removed. Each C-shaped electrode is arranged so that the ions will be injected perpendicularly to the ion-transport direction. The injected ions lose energy due to collision cooling, become converged onto the ion-beam axis C due to the ion-confining effect of a radio-frequency electric field, and efficiently move toward the exit aperture along a potential gradient created by a direct-current electric field. The gas stream carrying the ions passes through the gaps of the ring electrodes, without increasing the gas pressure at the exit of the ring-electrode inner space and thereby deteriorating the degree of vacuum in the next stage.

Mass spectrometer

A drift voltage generator applies voltages to a plurality of annular electrodes, respectively, so that a potential distribution &#x3c6; on an ion beam axis of an accelerating electric field created within a drift region satisfies &#x2202;&#x3c6;/&#x2202;Z&#x3e;0. Trailing ions undergo a higher rate of acceleration than preceding ions, so that a compressing force acts on an ion packet in the direction of the ion beam axis. Consequently, the ion packet is constantly confined to a smaller space in the direction of the ion beam axis, and ions having the same ion mobility form a narrower peak in a spectrum with the horizontal axis representing the drift time, so that the resolving power improves. A control unit switches the applied voltages so that a uniform accelerating electric field is created.

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Kyoto, Japan

Motohide Yasuno