Shimadzu Corporation

Ryo Fujita

Motohide Yasuno

Masaru Nishiguchi

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

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 shielding platehaving a forward-side slit openingand return-side slit openingis placed in a free flight spacewith no electric field. Ions which significantly deviate from a reference path are removed by the shielding plateon both the forward-side and return-side paths. The opening width of the forward-side slit openingis smaller than that of the return-side slit opening. Those opening widths and the placement position of the shielding plateare determined based on the result of an ion trajectory calculation by accurate simulation. As compared to a conventional device with a shielding plate placed only on the return side, the present configuration allows for an increase in the opening width of the return-side slit opening while achieving the same level of resolving power. The ion transmission ratio is thereby improved, and the analytical sensitivity is enhanced.

Time-of-flight 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.

Ion mobility analyzer and mass spectrometer

Shutter gate grid is a structure wherein first and second disc-shaped members made of metal with an insulation sheet member sandwiched therebetween are integrally joined by means of insulative screws. Gate grids with conductive wires secured to the central openings thereof are fused onto the disc-shaped members; screw insertion holes formed in the second disc-shaped member are fan-shaped and have play in the direction of rotation, making it possible to adjust the parallelism of the conductive wires of the two members by finely adjusting the rotational position when tightening the screws. Moreover, diffusion gas can be made to flow through ventilation holes provided at common locations on each member, thus making it possible to provide uniformity of diffusion gas flow in the drift region.

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Manchester, United Kingdom

Ryo Fujita