# US 9,040,902 B2 · Atmospheric pressure ionization mass spectrometer

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- Number: US 9,040,902 B2
- Document ID: US9040902B2
- Status: Granted
- Kind: B2
- Application number: 14/352,191
- Filed: 2011-10-17
- Published: 2014-09-25
- Granted: 2015-05-26
- Earliest claimed: 2011-10-17
- Assignees: Shimadzu Corporation
- Applicants: Manabu Ueda; Daisuke Okumura
- Inventors: Manabu Ueda; Daisuke Okumura
- Web page: https://patentgrep.com/patent/US9040902B2

## CPC

- H01J 49/04: Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components
- H01J 49/0445: {with means for introducing as a spray, a jet or an aerosol (electrospray ion sources H01J49/165)}
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

In an atmospheric pressure ionization source using an ESI or the like having a desolvation pipe with one end opening serving as an ion-drawing port, a drying-gas supplying port for supplying a drying gas against the ion-drawing direction is provided below the ion-drawing port, i.e. at a position opposite to the side where a nozzle for spraying a liquid sample into an atmospheric pressure atmosphere is located, as viewed from the ion-drawing port. When the drying gas is supplied from the drying-gas supplying port, the gas pressure becomes higher in a region above the ion-drawing port becomes higher than in a region below the same port and produces a downward air stream. This stream helps ions in the spray flow from the nozzle to easily come close to the ion-drawing port and be efficiently drawn into the desolvation pipe.

## Claims

### Claim 1

An atmospheric pressure ionization mass spectrometer having: a spray device for spraying a liquid into an ionization chamber whose inner space is maintained at atmospheric pressure; and an ion-drawing port for drawing ions generated from micro droplets sprayed from the spray device so as to transport the ions to a subsequent stage maintained at a low gas pressure, the central axis of the ion-drawing port being unidentical with the central axis of a spray flow from the spraying device, wherein:
the mass spectrometer includes a drying-gas supplying port located in a region surrounding the ion-drawing port and at least on a side of the central axis of the ion-drawing port opposite to a side where the spray port of the spraying device is located, the drying-gas supplying port being arranged so as to supply a drying gas in a direction opposite to a direction in which ions are drawn through the ion-drawing port; and
the drying gas is supplied only from the aforementioned drying-gas supplying port.

### Claim 2

An atmospheric pressure ionization mass spectrometer having: a spray device for spraying a liquid into an ionization chamber whose inner space is maintained at atmospheric pressure; and an ion-drawing port for drawing ions generated from micro droplets sprayed from the spray device so as to transport the ions to a subsequent stage maintained at a low gas pressure, the central axis of the ion-drawing port being unidentical with the central axis of a spray flow from the spraying device, the mass spectrometer including:
a) a plurality of drying-gas supplying ports provided around the ion-drawing port in such a manner as to surround the ion-drawing port; and
b) a flow rate regulator for independently regulating a flow rate of the drying gas supplied from each of the drying-gas supplying ports.

### Claim 3 (depends on 2)

The mass spectrometer according to claim 2, wherein:
the plurality of drying-gas supplying ports are arranged at regular intervals of angle on a circle concentric with the ion-drawing port.

### Claim 4 (depends on 2)

The atmospheric pressure ionization mass spectrometer according to claim 2, further comprising:
a controller for monitoring an ion detection signal while regulating each of the flow rates of the drying gas supplying from the drying-gas supplying ports through the flow rate regulator and for setting each of the flow rates of the drying gas so as to maximize an ion detection sensitivity.

### Claim 5 (depends on 3)

The atmospheric pressure ionization mass spectrometer according to claim 3, further comprising:
a controller for monitoring an ion detection signal while regulating each of the flow rates of the drying gas supplying from the drying-gas supplying ports through the flow rate regulator and for setting each of the flow rates of the drying gas so as to maximize an ion detection sensitivity.