Source: http://www.google.com/patents/US20040011951?ie=ISO-8859-1
Timestamp: 2015-03-31 12:02:52
Document Index: 156102282

Matched Legal Cases: ['art 60', 'art 70', 'art 60', 'art 70', 'art 60', 'art 60', 'arts 70', 'arts 70', 'art 60', 'art 70', 'art 60', 'art 70']

Patent US20040011951 - Multi-inlet mass spectrometer - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA mass spectrometer has an ion source (10) with a plurality of atmospheric pressure sample ioniser (20) mounted in a front face (15) thereof. Each sample ioniser (20) extends into a corresponding sample region (30) and the tip of each sample ioniser is mounted at right-angles to a corresponding one of...http://www.google.com/patents/US20040011951?utm_source=gb-gplus-sharePatent US20040011951 - Multi-inlet mass spectrometerAdvanced Patent SearchPublication numberUS20040011951 A1Publication typeApplicationApplication numberUS 10/333,867Publication dateJan 22, 2004Filing dateJul 26, 2001Priority dateJul 26, 2000Also published asCA2418212A1, CA2418212C, EP1303744A2, US6914240, WO2002008724A2, WO2002008724A3, WO2002008724A8Publication number10333867, 333867, US 2004/0011951 A1, US 2004/011951 A1, US 20040011951 A1, US 20040011951A1, US 2004011951 A1, US 2004011951A1, US-A1-20040011951, US-A1-2004011951, US2004/0011951A1, US2004/011951A1, US20040011951 A1, US20040011951A1, US2004011951 A1, US2004011951A1InventorsRoger Giles, Alexander Makarov, Lee EarleyOriginal AssigneeRoger Giles, Alexander Makarov, Earley Lee MartinExport CitationBiBTeX, EndNote, RefManReferenced by (7), Classifications (6), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetMulti-inlet mass spectrometer
US 20040011951 A1Abstract
A mass spectrometer has an ion source (10) with a plurality of atmospheric pressure sample ioniser (20) mounted in a front face (15) thereof. Each sample ioniser (20) extends into a corresponding sample region (30) and the tip of each sample ioniser is mounted at right-angles to a corresponding one of a plurality of entrance cones (50) each having entrance orifice (40) therein. Each entrance cone (50) in turn opens into an inlet channel having first and second parts (60, 70). The two parts of the inlet channel are separated by an electrical gate (65). The inlet channels corresponding to each entrance cone (50) all merge into a common exit channel (90) to a mass spectrometer. By appropriate operation of the gates (65) dividing the inlet channels, rapid switching between the samples that are analysed in the mass analyser can be achieved. Images(4) Claims(32)
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0026] Referring first to FIG. 1, an ion source, generally indicated at 10, is shown. [0027] The ion source 10 has a front face 15 and includes a plurality of atmospheric pressure sample ionisers 20, mounted therein. A variety of different ionisers are suitable, such as an electrospray ion source, an atmospheric pressure chemical ionisation (APCI) ion source or a matrix-assisted laser desorption/ionisation (MALDI) ion source. As will be familiar to those skilled in the art, the ioniser 20 is provided with a flow of solvent containing a sample to be analysed. Typically, this flow is produced by separating the sample molecules by liquid chromatography or capillary electrophoresis. However, other techniques such as fast liquid chromatography and capillary electrochromatography can be used as well. [0028] Each ioniser 20 extends into a corresponding sample region 30, which is again at or around atmospheric pressure. The sampling region 30 is defined between the end of each ioniser 20 and an entrance orifice 40 in an entrance cone 50. As will be understood, the tip of each ioniser is arranged at right-angles to the entrance orifice of the corresponding entrance cone 50, so that sample ions and entrained solvent molecules are not forced directly into the entrance orifice 40. [0029] Each entrance cone 50 communicates with a corresponding inlet channel which has a first part 60 and a second part 70 defined in an interface chamber 80. The first part 60 of the inlet channel meets the second part 70 of the inlet channel at an oblique angle as may be seen in FIG. 1. At the junction between the two parts of each inlet channel is an electrical gate 65, whose purpose will be described in detail below. [0030] Each inlet channel opens into a common exit channel 90, also defined in the interface chamber 80. Adjacent to the common exit channel 90 is an exit orifice 100 in an exit cone 110. The exit orifice allows ions within the common exit channel 90 to pass therethrough and into a mass spectrometer (not shown). [0031] The common exit channel 90 opens into a pumping chamber 120 to which is connected a vacuum pump, typically a rotary pump (not shown). In this manner, the pressure in the interface chamber 80, between the entrance orifices 40 and the exit orifice 100, is maintained below atmospheric pressure, typically around 10 to 15 mBar. [0032] In prior art ion sources having only a single entrance orifice such as are described in WO 98/49710, although the pressure at the exit orifice is about 10 to 15 mBar, the slow rate of gas flow means that the pressure on the pump is only about 1 mBar. In the system of WO 98/49710, a small restrictor is used to reduce pump efficiency and to maintain the required pressure. The same pump can then also be used as a backup pump to the more powerful turbo pumps which maintain the mass spectrometer at an even lower pressure (typically about 10−4 mBar). [0033] In a preferred embodiment of the present invention, the restrictor is removed to offset the increased gas flow rate caused by the introduction of a plurality of entrance orifices 40. In this way, the required pressure in the interface chamber 80 may be maintained without the introduction of a second vacuum pump. However, it may be necessary for a system having 8 to 10 entrance orifices 40, for example, to provide a further, lower pumping speed pump to act as a backup to the turbo pumps. [0034] Turning now to FIG. 2, a section along the line AA′ of FIG. 1 is shown. FIG. 2 illustrates the layout of the plurality of inlet channels and entrance cones which are fed by the corresponding plurality of ionisers. As seen in that Figure, eight inlet channels are arranged in a circle, to allow samples from eight different ionisers to be received. Each entrance cone 50 receives samples from a corresponding sample ioniser, and these pass into a corresponding first part 60 of a corresponding inlet channel. For example, the entrance cone labelled 50A opens into a first part (not shown in FIG. 2) of the inlet channel. This in turn leads into a second part 60A of the inlet channel. Adjacent inlet channels are separated by ribs 130. [0035] As may be appreciated through considering FIGS. 1 and 2 in combination, the second parts 70 of the separate inlet channels converge at a relatively shallow angle, meeting at the common exit channel 90. Thus, the eight second parts 70 of the inlet channel together form a frustoconical shape. The shallow angle between the inlet channels and the common exit channel 90 prevents excessive turbulence in ions as they approach the exit orifice 100. [0036] In use, each of the eight ionisers 20 typically supplies different sample ions. However, it is to be appreciated that at least some of the ionisers may in fact receive the same sample from the liquid chromatograph (for example). This could improve the sensitivity of the device. [0037] In contrast to prior art devices, each of the ionisers 20 generates sample ions continuously, rather than being switched on and off as required. Thus, ions from each of the separate ionisers travel through the corresponding entrance orifices 40 in the entrance cone 50 corresponding to that particular ioniser. The different sample ions then travel down their own, separate inlet channels. In other words, absent an electrical gate 65 in each inlet channel, all eight different samples would arrive continuously, together, at the exit orifice 100. [0038] The electrical gate 65 in each inlet channel is, as previously described in connection with FIG. 1, located at the junction between the first part 60 and the second part 70 thereof. In the exemplary embodiment of FIG. 1, the electrical gate 65 is formed from an electrode which is capable of generating an electric field of suitable magnitude to deflect the sample ions passing down the first part 60 of the inlet channel, onto the wall of the interface chamber 80. This prevents them from passing along the second part 70 of the inlet channel and into the common exit channel 90. [0039] Each of the eight electrodes mounted, separately, in the eight inlet channels, is connected to a common controller. This allows a user to determine which of the samples is to be allowed to pass along the length of the inlet channel and into the common exit channel 90. In one mode, the electrodes are manually switchable such that, at a given time, the electrical gates 65 in seven of the eight inlet channels are �closed�, and only one of the electrical gates 65 is �open�. In a second mode, the controller may automatically switch the electrical gates 65 in rapid succession such that successively different samples are admitted into the common exit channel 90. In yet a further mode, two or even more of the electrical gates 65 may be open simultaneously. This would be useful, for example, when species from separate flows are known not to interfere in the mass spectrum and therefore the duty cycle could be increased. [0040] The bend in the inlet channel at the junction between the first and second parts thereof serves two purposes. Firstly, it avoids the presence of a direct line of sight between any of the entrance orifices 40 and the single exit orifice 100. This prevents �streaming� of sample ions from the entrance to the exit orifices, which is advantageous. Secondly, by locating the electrode to generate the electrical gate 65 at that junction, the electric field shape is particularly efficient in preventing ions from travelling through the inlet channel when the electrical gate 65 is closed. [0041] Although all eight ionisers 20 may provide ions from a sample to be examined, it is preferable that one of the ionisers 20 is instead provided with a flow of solvent containing molecules which, when ionised, have a known mass/charge ratio. This is particularly useful to allow a mass spectrometer in communication with the exit orifice 100 to be calibrated. In this case, the inlet channel fed by the calibration ioniser is typically left open (that is, the electrical gate 65 in that channel is opened) whilst a sample to be analysed (from another of the ionisers) is admitted at the same time. [0042] Gating of the different inlet channels allows for any combination of the different streams of sample ions to be mass analysed. Further, the high speed electrical gating enables fast switching from one stream of sample ions to the next, increasing the speed of analysis by the mass spectrometer. Typically, the interface chamber 80 is maintained at a pressure of around 10 to 15 mBar. Accordingly, the sample ions in the inlet channel are typically travelling at speeds of over 100 m/s in comparison to speeds of around 10 m/s in the relatively higher pressure sample region 30 surrounding the entrance orifice 40. With this increased speed of travel, when one of the electrical gates 65 is open, the relaxation time before the sample ions reach the exit orifice 100 is considerably shorter than in the prior art. This increases the switching speed, and hence the speed of analysis by the mass spectrometer, yet further. [0043] Although a preferred embodiment of the invention has been described, it is to be understood that various modifications or alternatives are contemplated. In particular, any number of sample ionisers 20, together with a corresponding number of entrance cones 50 and inlet channels, may be included, and these may be arranged in any suitable configuration. However, increasing the number of entrance orifices 40 will increase the pressure in the interface chamber 80 for a given pumping speed. [0044] Furthermore, although in the preferred embodiment an electrical gate 65 is employed in each inlet channel, at the junction between the first and second parts thereof, it would be appreciated that different techniques may be used for gating or blocking the ions. For example, a mechanical gate such as a shutter valve could be used in place of an electrical gate generated by an electrode, to block the flow of sample ions through each inlet channel. Furthermore, rather than using a static electric field, it may be advantageous under certain circumstances to employ an RF field instead. [0045] In an alternative embodiment of the present invention, shown in FIGS. 3 and 4, instead of a plurality of electrical or electrically-operated mechanical gates, the multiple ion paths from the ionisers via the interface chamber to the mass spectrometer may instead be selectively blocked by a plurality of rf-only multipole storage devices (such as a quadrupole or hexapole arrangement). These are of themselves well known and are shown, for example, in U.S. Pat. No. 5,420,425, U.S. Pat. No. 6,020,586 and U.S. Pat. No. 5,179,278. [0046] Referring to FIG. 3, two of a plurality of sample ionisers 20 (e.g. nanosprays) are shown, each extending into a corresponding sampling region 30, and pointing directly at an associated entrance orifice 40 of an entrance cone 50. It will be understood that, as with previous embodiments, each sample ioniser 20 may be arranged at right-angles to its associated entrance orifice 40. Each entrance cone 50 communicates with a corresponding inlet channel 60, defining an ion path. [0047] Electrodes of an rf-only multipole ion trap 65 are shown arranged around each inlet channel 60. Preferably, one rf-only ion trap 65 is positioned in a corresponding one of the ion paths between the entrance orifices 40 and the exit orifice 100, that is, a separate storage device 65 is provided for each ion stream within the multipole arrangement. [0048] The common exit channel 90 opens into a pumping chamber 120 to which is connected a vacuum pump, typically a rotary pump (not shown). [0049] During operation, the ions from a given ioniser 20, passing along the corresponding inlet channel 60, are focussed onto the axis of the ion trap 65 associated with that inlet channel 60, even at relatively high pressures (several mBar). Ions may be trapped in each ion trap 65 by applying a voltage to the end apertures or end-sections thereof and the storage time may be up to a few seconds. Once trapped, ions may be ejected by altering the ion trap parameters when desired. Thus, in a directly analogous manner to the use of electrical or mechanical gates, ion traps 65 can simultaneously or sequentially supply a single stream of ions to a mass spectrometer from a multiple sample stream input. The advantage of this arrangement over the electrical/mechanical gating technique is that the ion traps should provide a 100% duty cycle. This in turn permits higher sensitivity to be achieved. Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7145650 *Feb 20, 2003Dec 5, 2006Perkinelmer Las, Inc.Method of instrument standardization for a spectroscopic deviceUS7189965Jun 9, 2005Mar 13, 2007Bruker Daltonik GmbhStorage device for molecular detectorUS7405821Oct 24, 2006Jul 29, 2008Perkinelmer Las, Inc.Method of instrument standardization for a spectroscopic deviceUS7656521May 12, 2008Feb 2, 2010Perkinelmer Las, Inc.Method of instrument standardization for a spectroscopic deviceUS8809775Aug 10, 2010Aug 19, 2014Shimadzu CorporationCurtain gas filter for high-flux ion sourcesDE102004028638B4 *Jun 15, 2004Feb 4, 2010Bruker Daltonik GmbhSpeicher f�r molekularen DetektorWO2012021124A1 *Aug 10, 2010Feb 16, 2012Shimadzu CorporationCurtain gas filter for high-flux ion sources* Cited by examinerClassifications U.S. Classification250/285, 250/288International ClassificationH01J49/10, H01J49/04Cooperative ClassificationH01J49/107European ClassificationH01J49/10SLegal EventsDateCodeEventDescriptionDec 28, 2012FPAYFee paymentYear of fee payment: 8Jan 2, 2009FPAYFee paymentYear of fee payment: 4Apr 1, 2003ASAssignmentOwner name: THERMO FINNIGAN LLC, CALIFORNIAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:THERMO MASSLAB LIMITED;REEL/FRAME:013897/0313Effective date: 20020515Owner name: THERMO FINNIGAN LLC 355 RIVER OAKS PARKWAYSAN JOSEFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:THERMO MASSLAB LIMITED /AR;REEL/FRAME:013897/0313Jan 25, 2003ASAssignmentOwner name: THERMO MASSLAB LIMITED, UNITED KINGDOMFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GILES, ROGER;MAKAROV, ALEXANDER;EARLEY, LEE MARTIN;REEL/FRAME:014412/0660;SIGNING DATES FROM 20020801 TO 20020805Owner name: THERMO MASSLAB LIMITED, UNITED KINGDOMFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GILES, ROGER;MAKAROV, ALEXANDER;EARLEY, LEE MARTIN;REEL/FRAME:014354/0506;SIGNING DATES FROM 20020108 TO 20020801Owner name: THERMO MASSLAB LIMITED CREWE ROAD, WYTHENSHAWEMANCFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GILES, ROGER /AR;REEL/FRAME:014412/0660;SIGNING DATES FROM 20020801 TO 20020805Owner name: THERMO MASSLAB LIMITED CREWE ROAD, WYTHENSHAWEMANCFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GILES, ROGER /AR;REEL/FRAME:014354/0506;SIGNING DATES FROM 20020108 TO 20020801RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services