DE10351010A1 - Magnet sector mass spectrometer includes divider producing two ion beams each with a detector of ion beam intensity - Google Patents

Abstract

A collector slit following the magnet sector mass analyzer, is followed by a divider producing two ion beams, each with a detector of ion beam intensity.

Description

The present invention relates to a magnetic sector mass spectrometer and a method for mass spectrometry.

Magnetic sector mass spectrometers are commonly used for target component trace analysis, for precise mass measurements, for isotope ratio measurements and for basic ion chemistry studies are used. Magnetic sector mass spectrometer are for it set up ions with a certain mass-to-charge ratio pass through an ion detector. As in more detail below ions are traversed in a substantially circular trajectory through the magnetic sector mass analyzer. A magnetic sector mass analyzer can be described in more detail as an ion pulse analyzer if however, the initial energies of the ions are essentially the same, the ions are separated according to their mass-charge ratio.

und daher:

If ions with a mass m and a charge ze are accelerated by an electrical potential difference V, they reach a velocity v and have a kinetic energy ε, where:

and therefore:

Ions with a charge ze, which move through a magnetic field B at a velocity v, are subject to a Lorentz force F in a direction orthogonal to the direction of the magnetic field and also to the direction of movement of the ions. The Lorentz force F exerts a centripetal force on the ions, as a result of which they are caused to run on a circular trajectory with a radius r _m . The Lorentz force F is.

und es gilt daher:

Accordingly, the mass-to-charge ratio of the ions passing through the magnetic field is given by:

and therefore:

Therefore, by removing v ² from the above equation for the mass-charge ratio:

This shows that the values of the Magnetic field B and the potential difference V are set so can, that ions with a certain mass to charge ratio from an ion source received, passed from the magnetic sector to the ion detector become. In this way, the magnetic sector acts as a mass-to-charge ratio filter. Accordingly, a mass spectrum can be obtained by scanning either the Magnetic field B and / or the potential difference V are recorded.

For some applications can multiple ion detectors are provided so that ions with different mass-charge ratios at the same time can be recorded each ion taking on a different trajectory through the magnetic sector. Alternatively, an array of detectors can be used to simultaneously record part of the mass spectrum.

According to another arrangement, the magnetic field can be kept essentially constant, so that ions are dispersed according to their momentum. The momentum ρ of an ion with a mass m, a velocity v and a kinetic energy ε is given by: ρ = mv = √ 2mε

Therefore ions with a constant kinetic energy ε effective dispersed according to their mass.

The shape of a magnetic sector can be interpreted so that they Has ion direction focusing properties. A magnetic sector mass analyzer can be designed so that it a certain combination of mass dispersion and directional focusing properties in the direction of the mass dispersion.

A conventional single focus magnetic sector mass spectrometer has an ion source, a magnetic sector mass analyzer and a collector slot. The ion source has a limited emission area or a limited slot width, which defines the width of the ion beam emitted by the ion source. The magnetic sector mass analyzer may have convergent directional focusing properties to focus the ions onto a pixel in a focal plane downstream of the magnetic sector mass analyzer. In a single-focusing magnetic sector mass spectrometer, an ion collector slot is at the pixel of the ion source slot orderly. The directional focusing properties of the magnetic sector mass analyzer can be set to a very high degree. However, the imaging properties of the magnetic sector mass analyzer are limited by the width of the initial energy of the ions.

The mass dispersion coefficient D _{m of} a single-focusing magnetic sector mass spectrometer is proportional to the radius of curvature rm of the ion trajectory in the magnetic field. The spatial separation y of two ions with different masses of an average mass m and a mass difference Δm relates to the mass dispersion coefficient D _m and is:

The ion beam width w _b at the image position downstream of the magnetic sector mass analyzer is related to the slit width w _{s of} the ion source, the lateral magnification M of the image and the sum of the image aberration coefficients Σα as follows: w b = Mw s + Σα

The mass resolution m / Δm for a collector slot with a collector slot width w _c is given by:

Accordingly, the mass dispersion coefficient D _m , the ion source slit width w _s and the collector slit width w _{c are} the most important parameters in determining the mass resolution of a magnetic sector mass spectrometer. However, the ultimate mass resolution is limited by the sum of the aberrations.

As discussed above, magnetic sectors disperse that use a constant magnetic field, ions with respect to the Ion pulse and therefore with reference to the ion mass if the ions are monoenergetic are. However, ions are usually not monoenergetic and often show dependent the special type of ion source used to generate the ions, a range of kinetic energies. The width of the ion energies causes the ion beam width wb to widen at the image position, and this typically becomes the limiting factor in reaching a high resolution.

The pulse dispersion can be viewed as having a combination of a mass dispersion and an energy dispersion. Electrical sectors are known which disperse ions according to their energy. Accordingly, if an electrical sector is combined with a magnetic sector, the total energy dispersion of the ions can be modified. Dual focus magnetic sector mass analyzers are known that have a combination of a magnetic sector mass analyzer and one or more electrical sectors, providing directional focus and wherein the total energy dispersion is zero. If the double-focusing magnetic sector mass analyzer has an electrical sector with an energy dispersion D _e1 and a magnetic sector with an energy dispersion D _e2 , the image magnification being M ₂ , the total energy dispersion D _{e of} the double-focusing magnetic sector mass spectrometer is: D e = M 2 D e1 + D e2

The electrical sector may precede or follow the magnetic sector, or alternatively two smaller electrical sectors may be provided, one upstream of the magnetic sector and the other downstream of the magnetic sector. As long as the total energy dispersion D _{e is} zero, the arrangement can be seen as a double focusing magnetic sector mass analyzer. A combination of magnetic and electrical sectors can be established that do not have the image broadening problems associated with a single focus magnetic sector mass spectrometer. Accordingly, double-focusing magnetic sector mass spectrometers are able to achieve much higher resolutions than single-focusing magnetic sector mass spectrometers.

The combination of a magnetic sector and one or more electrical sectors to provide of a double focusing magnetic sector mass spectrometer enables at Design choice sufficient degrees of freedom to achieve a Focusing relatively higher To enable order. Dual focus magnetic sector mass spectrometers, where all directional and energy focusing terms are near or substantially zero, are known, and these mass spectrometers can have resolutions corresponding to more than 150,000 the 10% valley definition (which is described in more detail below will reach.

The mass resolution for a peak width in units of mass of Δm with the mass m is m / Δm. If the peak _width w _{pk is measured} at the base, the mass resolution m / Δm for an ion beam width wb and a collector slot width w _{c is} theoretically given by:

However, it is not practical to use the top porridge te at the base, and the tip width is therefore conventionally measured at 5% of the tip height. The peak width measured at 5% of the height is used to calculate the resolution. This is known as the 10% definition of the resolution because, if two peaks of different mass, but of the same intensity or height, overlap or intersect at a point 5 times their height, the resulting peak profile will have two peaks with an intermediate one Valley that is 10% of the height of the peaks. If, for example, a magnetic sector mass spectrometer had a mass resolution of 1000 corresponding to the 10% valley definition, two identical intensity peaks with masses 1000 and 1001 so that the valley between the peaks of the resulting peak profile would be 10% of the height of the two peaks.

As discussed above, the spatial separation y of two ions with different masses with an average mass m and a mass difference Δm is related to the dispersion coefficient D _m . This relationship can be used to express the real width of an ion beam w _b at the collector slot with respect to the fractional mass difference of the ions Δm / m as follows:

The term for the fractional mass difference of the ions Δm / m is dimensionless and is typically expressed in parts per million (ppm), where:

Accordingly, the beam width w _b can be expressed in ppm of the mass if the dispersion coefficient D _{m of} the mass spectrometer is known. The collector slot width w _c can also be expressed in ppm by mass as follows:

If an ion beam with the width w _{b is} deflected via a collector slot with the width w _c and the transmitted ions are detected and recorded, the recorded peak _profile has a width w _pk , where:

The peak _width w _pk can also be expressed as ppm of the mass:

The reciprocal of the mass resolution m / Δm of the mass analyzer gives the mass resolution Δm / m. Therefore can the mass resolving power as that expressed in ppm by mass Peak width can be viewed.

The capacity of double focusing magnetic sector mass spectrometers for one high resolution leads to their use for accurate mass measurements and for a highly specific target compound trace analysis by an as high-resolution High Resolution Selective Ion Recording (HR-SIR) known technology. With conventional high-resolution selective ion recording techniques becomes a double focusing Magnetic sector mass spectrometer used to respond to Target connections at high resolution and with high sensitivity select and record. The high resolution allows that chemical Background masses are effectively eliminated, and consequently enables reaching a lower detection level. The high-resolution selective Ion recording therefore offers a higher duty cycle than other conventional Techniques and thus opposite this an improved sensitivity.

The detection and quantification of polychlorinated dibenzo-p-dioxins and in particular of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin ("2,3,7,8-TCDD") is a particularly important application of double-focusing magnetic sectors. Mass spectrometry. Despite costly purification procedures, samples still contain compounds such as polychlorinated biphenyls and benzylphenyl ethers that have the same nominal masses as the compounds of interest. Samples traditionally have peaks with a known amount of a form of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin labeled as ¹³ C-isotope that was introduced by gas chromatography and recorded by high resolution mass spectrometry. The measurement is quantified by comparing the response with that of the native dioxin marked as ¹³ C shape and checked by confirming the ratio between the major isotopes of both the native and the labeled as ¹³ C dioxin. With a resolution of 10,000 (10% valley definition), the conventional detection level for 2,3,7,8-tetrachlorinated dibenzo-p-dioxin is approximately 1 femtogram or 3 attomol in the absence of other interfering components.

A magnetic sector mass spectrometer with a single ion detector can be used to record a mass spectrum by scanning and then detecting different mass peaks. The duty cycle for recording each mass in the mass spectrum is generally relatively low, and the higher the resolution or the wider the mass range, the lower the duty cycle. Different to Quadrupole mass filter, a magnetic sector mass analyzer can be designed to record the signal of ions with several different masses simultaneously. This is commonly referred to as parallel detection.

Several detectors form an average to accurately record the relative frequency of two or more different masses at the same time. The simultaneous accurate recording the relative frequencies of two isotopes, for example, is particularly accurate because these Technology essentially not due to fluctuations or drift the ionization source or due to rapidly changing sample concentrations, the often occur for example in chromatography, is influenced. Magnetic sector mass spectrometer, which have multiple collector slots, and corresponding separate discrete ones Ion detectors can therefore used to make accurate isotope ratio determinations. Different ion detectors are required to make different ones Record masses, but only at a low resolution of for example 200-300 (10% valley definition).

According to another conventional one Arrangement allows a field detector allows simultaneous detection over a mass range, which means that duty cycle is improved when used to record a mass spectrum is used. Field detectors where high density fields are more discrete charge sensitive detectors or individual ones sensitive to the ion position Detectors used are very sensitive, but they are usually limited in size. Such field detectors are placed along the focal plane of the mass spectrometer and therefore replace the collector slot that would otherwise normally be in connection with an ion detector in a magnetic sector mass spectrometer is used. Each separate detector in the field therefore replaces the collector slot, and determine these separate detectors the resolution of the mass spectrometer. Because the detector has several masses at the same time must record in practice it can only be used up to a medium resolution, for example up to a resolution operated by about 2000 (10% valley definition). This resolution is for the Analysis of polychlorinated dibenzo-p-dioxins still too low.

Conventional high resolution recording techniques selected Ions for detect the detection of traces of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin repeated rapid switching to at least four different masses high resolution and a record of the signal response for all four masses. This is commonly used with a mass resolution of around 10,000 (10% valley definition) executed to ensure, that others isobaric components that elute from the gas chromatography column, be separated out. In practice, there is usually an additional one Reference material continuously into the ion source of the mass spectrometer introduced so that a additional Reference mass peak that is close to the mass of the analyte Track connection is present continuously. The additional Reference ground is included in the switching sequence, so that every drift monitored on the mass scale and can be corrected. The drift on the mass scale can be caused by Scan over monitors the reference peak to determine each shift in the top center. If a drift on the mass scale is not monitored, the switching could to the top of each of the four masses of interest not be carried out with the required degree of accuracy. It is also known to occur at a second time in each sequence toggle the reference tip to confirm that the shift is correct and works exactly. This procedure ensures precise switching at a resolution of 10000 (10% valley definition). Although this procedure is sensitive is guaranteed however, they don't all actually detected ions exclusively Are ions of the target compound of interest. Accordingly can Interference ions can also be detected unintentionally.

For example, interference ions due to impurity materials in the ion source, reference material, leaking material from the gas chromatograph column or other components that co-elute from the gas chromatograph, the very similar Mass-to-charge ratios how the intended analyte ions have can be detected. This Interference ions can can be detected because even with a resolution of 10000 (10% valley definition) not completely separated from the analyte ions can be. Interference ions can diffusion due to ions from other components result with the higher frequency are present and collide with residual gas molecules.

The main indication of existence A significant interference is a distortion in the isotope ratio. Such distortion is usually part of a standard test procedure checked. However, even if it is known that interference ions are present by recognizing that certain isotope ratio is distorted, carries the presence of the interference ions further a background signal which cover the detection of the trace analyte ions of interest can. Switching from tip to tip offers nothing in itself Way to check if the detected ions actually are the ions of interest, and it also doesn't help to make a determination that the measured ion signal rejected due to significant presence of interference ions should be.

It is therefore desirable to have an improved magnetic sector mass spectrometer provide.

According to the present invention there is provided: a magnetic sector mass spectrometer with a magnetic sector mass analyzer, a collector slot that is downstream of the magnetic sector mass analyzer is arranged and a device which is downstream of the Collector slot is arranged to one of the collector slot transmitted ion beam into at least a first and a first to disassemble the second ion beam. The mass spectrometer further includes a first detector for measuring the intensity of at least a portion of the first ion beam and a second detector for measuring the intensity at least part of the second ion beam.

The ion beam has a first and a second direction that are orthogonal to each other. According to the preferred embodiment the ions in the ion beam according to their mass-to-charge ratio in dispersed in the first direction, so that the mass-to-charge ratio of Ions in the ion beam change along the first direction. Preferably the ions in the ion beam are essentially not corresponding their mass-to-charge ratio in dispersed in the second direction, so that the mass-to-charge ratio of the Ions in the ion beam along the second direction substantially is constant.

Measure according to the preferred embodiment the first and the second detector the intensities of at least a part of the first and second ion beams at substantially the same time.

The mass spectrometer can be a simple focusing Magnetic sector mass spectrometer or a double focusing Include magnetic sector mass spectrometer.

According to the preferred embodiment the device for dividing the transmitted through the collector slot Ion beam an electrode. The electrode is on one Potential held that ions reflected or deflected onto the first and second detectors become. The electrode closes preferably a sheet with a fine edge or a wedge-shaped electrode a, and it can be ensured in use that analyte ions substantially uniform and / or in the ion beam approaching the edge be arranged symmetrically with respect to the edge. interference ions in the ion beam, which approach the edge of the electrode, can be in the substantially uneven and / or be arranged asymmetrically with respect to the edge.

The magnetic sector mass spectrometer has preferably an electron impact ion source ("EI ion source") or an ion source with chemical ionization ("CI ion source"). Alternatively, you can the ion source is an electrospray ion source ("ESI ion source"), an atmospheric pressure ion source with chemical ionization ("APCI ion source"), an atmospheric pressure photoionization ion source ("APPI ion source"), a matrix-assisted laser desorption ionization ion source ("MALDI ion source"), a laser desorption ionization ion source ("LDI ion source"), an inductively coupled Plasma ion source ("ICP ion source"), an ion source with rapid atomic bombardment ("FAB ion source"), a liquid secondary ion mass spectrometry ion source ("LSIMS ion source"), a field ionization ion source ("FI ion source") and include a field desorption ion source ("FD ion source"). The Ion source can be a continuous or a pulsed ion source his.

Preferably between the device for Parts of the ion beam and the ion source have a voltage difference maintained. The voltage difference can be 0 - 100 V, 100 - 200 V, 200-300 V, 300-400 V, 400-500 V, 500-600 V, 600-700 V, 700-800 V, 800-900 V, 900-1000 V or more than 1000 V.

The preferred magnetic sector mass spectrometer may further include a processor to determine the intensity at least part of the first ion beam with respect to the intensity of at least one Have part of the second ion beam. If the intensity at least a part of the first and / or the second ion beam from the Intensity at least a part of the second and / or the first ion beam by at least x percent deviates, it can be determined that the ion beam has a considerable Proportion of interference ions. The percentage is preferred x from that of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 or more than 100 selected group. Alternatively or additionally can, if within a time t the number of times from the first detector of the number of ions detected by the second detector Ions by at least y standard deviations of the total number from first and from the second detector detected during the time t If the ions deviate, it can be found that the ion beam has a significant Proportion of interference ions. Preferably the number is of the standard deviations y selected from the group consisting of 0, 25, 0, 5, 0, 75, 1, 0, 1, 25, 1, 5, 1, 75, 2, 0, 2, 25, 2, 5, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0 or more than 4.0.

In a preferred embodiment, the signals from the first and second detectors are summed to produce a combined signal and the combined signal can be multiplied by a weight factor. Preferably, the weighting factor does not significantly weaken the combined signal if the signal from the first detector is substantially the same as the signal from the second detector. Additionally or alternatively, the weight factor can significantly weaken the combined signal if the signal from the first detector differs significantly from the signal from the second detector. According to one embodiment, the Weight factor of the form exp (-ky ⁿ ), where k and n are constants and within a time t the number of ions detected by the first detector increases by y standard deviations of the total number of ions detected by the first and second detector during time t the number of ions detected by the second detector. According to this embodiment, the difference between the number of ions detected by the first and second detectors is assumed to be a positive value, ie the modulus of the difference between the number of ions detected. The constant k is preferably 0.5-2.0, 0.6-1.8, 0.7-1.6, 0.8-1.4, 0.9-1.2, 0.95-1 , 1 or 1. The constant n is preferably 1.0-3.0, 1.2-2.8, 1.4-2.6, 1.6-2.4, 1.8-2.2, 1,9 - 2,1 or 2.

According to the preferred embodiment, if it is found that the Ion beam has a significant proportion of interference ions, signals discarded by the first and / or second detector or to others Way as relatively inaccurate considered. Alternatively, if it is determined that the ion beam does not have a significant proportion of interference ions Signals from the first and second detectors are summed or otherwise as relatively accurate considered.

The magnetic sector mass spectrometer preferably has continue one downstream of the collector slot arranged lens. The lens can Image of the collector slot on the device for disassembling the Refocus ion beam or the ion beam essentially collimate.

According to another embodiment is a shielding tube for guiding of ions to the device to split the ion beam. The shield tube is preferably between the collector slot and the device for splitting the ion beam and can the ion beam from the first and / or the second Shield the applied voltages. Preferably, the first and / or second detector one, two, three, four, five, six, seven, eight, nine, ten or more than ten microchannel plate detectors on. additionally or alternatively can the first and / or the second detector one, two, three, four, five, six, seven, eight, nine, ten or more than ten conversion dynodes to generate of electrons in response to ions being converted to the conversion dynode (s) fall, have. The mass spectrometer can additionally one or multiple electron multipliers and / or one or more microchannel plate detectors for receiving have electrons generated by the conversion dynodes. According to one another embodiment the mass spectrometer further has one or more scintillators and / or one or more phosphors, of which those of the Conversion dynode or the conversion dynodes generated electrons be received so that the one or more scintillators and / or the one or more multiple phosphors in response to receiving electrons Generate photons. The mass spectrometer can also have one or more Photo photomultiplier tubes and / or one or more photosensitive solid-state detectors to detect the photons.

According to the preferred embodiment the magnetic sector mass spectrometer continues upstream of the first and the second detector arranged additional Detector on. This additional Detector may have a conversion dynode and in an operating mode is at least part of an ion beam on the conversion dynode of the additional Detector distracted so that the Conversion dynode generates electrons in response. The additional The detector can also have one or more electron multipliers and / or one or more microchannel plate detectors for receiving the have electrons generated by the conversion dynode. One or more Scintillators and / or one or more phosphors can also be provided to electrons generated by the conversion dynode to receive and generate photons in response. This Photons can through one or more photomultiplier tubes and / or one or more photosensitive solid-state detectors are detected.

Preferably, the gain of first and / or the second detector can be set independently, and according to one Embodiment the first and the second detector through independently adjustable power supplies fed. The first and second detectors can also have one or more Have analog-digital converter and / or one or more ion count detectors.

According to another preferred embodiment the magnetic sector mass spectrometer has further setting means for centering the ion beam on the disassembling device of the ion beam. The setting means preferably have at least one downstream of the collector slot arranged deflection electrode, which is set up for this is the ion beam with respect to the device for decomposing the To move the ion beam.

The magnetic sector mass spectrometer according to the preferred embodiment is particularly suitable for target connection trace analysis.

In another aspect, the present invention provides a method for mass spectrometry. The method has the following steps: passing an ion beam through a magnetic sector mass analyzer and a collector slot arranged downstream of the magnetic sector mass analyzer, dividing the ion beam downstream of the collector slot into at least a first and a second ion beam, measuring the intensity of at least a part of the first Io NEN beam with a first detector and measuring the intensity of at least a portion of the second ion beam with a second detector.

The ion beam has a first one Direction and a second orthogonal direction. According to the preferred Process the ions in the ion beam according to their Mass-to-charge ratio dispersed in the first direction so that the mass-to-charge ratio of Ions in the ion beam change along the first direction. Preferably the ions in the ion beam are essentially not corresponding their mass-to-charge ratio in dispersed in the second direction, so that the mass-to-charge ratio of Ions in the ion beam along the second direction substantially is constant.

Measure according to the preferred embodiment the first and the second detector the intensities of at least a part of the first and second ion beams substantially simultaneously. at The method also uses the intensity of at least a part of the first ion beam with respect to the intensity of at least a portion of the second ion beam determined. If the intensity at least a part of the first and / or the second ion beam from the intensity at least part of the second and / or the first ion beam deviates by at least a percentage x, it can be determined that the Ion beam has a significant proportion of interference ions. The percentage x can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 or greater than Be 50. Alternatively or additionally can, if within a time t the number of the first detector of the number of ions detected by the second detector Ions by at least y standard deviations of the total number from first and from the second detector detected during the time t If ions deviate, it can be found that the ion beam accounts for a significant proportion of interference ions. The number of standard deviations is preferred y 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, 3.0, 3 , 25, 3.5, 3.75, 4.0 or greater than 4.0.

According to a preferred embodiment, the method further sums signals from the first and second detectors to produce a combined signal, and the combined signal is multiplied by a weight factor. The weight factor preferably does not significantly weaken the combined signal if the signal from the first detector is essentially the same as the signal from the second detector. Additionally or alternatively, the weight factor can significantly weaken the combined signal if the signal from the first detector differs significantly from the signal from the second detector. According to one embodiment, the weight factor is of the form exp (-ky ⁿ ), where k and n are constants and within a time t the number of ions detected by the first detector from the number of ions detected by the second detector by y standard deviations from the total number of the ions detected by the first and second detectors during time t. According to this embodiment, the difference between the number of ions detected by the first and second detectors is taken as a positive value. The constant k is preferably 0.5-2.0, 0.6-1.8, 0.7-1.6, 0.8-1.4, 0.9-1.2, 0.95-1 , 1 or 1. Preferably the constant n is 1.0 - 3.0, 1.2 - 2.8, 1.4 - 2.6, 1.6 - 2.4, 1.8 - 2.2, 1,9 - 2,1 or 2.

If determined according to the preferred method will that the Ion beam has a significant proportion of interference ions, can they Signals from the first and / or from the second detector are rejected or in some other way as relatively imprecise be considered. Alternatively, if it is determined that the ion beam signals have no significant proportion of interference ions summed by the first and second detectors or otherwise as relatively accurate be considered.

Various embodiments of the present Invention will now be used, along with other arrangements, for illustrative purposes only serve only as an example with reference to the attached drawing described, whereby:

1 shows a conventional simple focusing magnetic sector mass spectrometer,

2 shows a conventional double focusing magnetic sector mass spectrometer,

3 shows a conventional measurement of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin obtained by high resolution selective ion recording,

4 shows an ion detector according to a preferred embodiment of the present invention,

5 1 shows an embodiment in which a lens is used to focus an ion beam that has passed through a collector slot onto the input opening of an ion detector according to the preferred embodiment,

6 shows a particularly preferred embodiment in which ions are detected using conversion dynodes in combination with microchannel plate detectors,

7 another embodiment shows two detectors are provided on each side of a reflective electrode,

8th 1 shows an embodiment in which ions can be directed to a preferred ion detector in one operating mode and ions can be deflected to a second detector system in another operating mode,

9 shows a typical peak profile that can be observed using a conventional ion detector,

10 shows the tip profiles, which under Ver using an ion detector according to the preferred embodiment,

11 shows the effect of a small positional shift of an ion beam having 20 ions falling on the collector slot of an ion detector according to the preferred embodiment with a high resolution of 10,000, and

12 shows the effect of a small shift in the position of an ion beam having 100 ions falling on the collector slot of an ion detector according to the preferred embodiment with a low resolution of 2000.

A conventional simple focusing magnetic sector mass spectrometer is in 1 shown. The mass spectrometer has an ion source 1 , a magnetic sector mass analyzer 2 and a collector slot 3 on, which is arranged immediately upstream of an ion detector (not shown). The ion source 1 has a slot 4 on which is the width of one from the ion source 1 emerging ion beam. The in 1 shown magnetic sector mass analyzer 2 has convergent directional focusing properties. An ion collector slot 3 is at the pixel of the ion source slot 4 arranged so that a single-focusing magnetic sector mass spectrometer is provided. Although the directional focusing properties of the single focus magnetic sector mass spectrometer can be designed to reach a very high level, its imaging properties are due to the energy width of the ion source 1 emitted ions limited.

2 shows a conventional double focusing mass spectrometer. The mass spectrometer has an ion source 1 with a source slit 4 on. Ions from the ion source 1 run through a first electrical sector 5 and become a first intermediate picture 6 brought. The ions then pass through the magnetic sector mass analyzer 2 and become a second intermediate picture 7 brought before focusing on a collector slot 3 through a second electrical sector 8th to run. The electrical sectors 5 . 8th serve to reduce the dispersion of ions with different energies, which would otherwise increase the width of the image and which would therefore limit the resolution of the mass spectrometer.

3 Figure 3 shows a conventional measurement of signal intensity as a function of retention time in a gas chromatograph for a solution containing 5 fg 2,3,7,8-tetrachlorinated dibenzo-p-dioxin using a conventional double focusing magnetic sector mass spectrometer with a resolution of 10,000 (10% valley definition) was analyzed, which was set to monitor ions with a molecular weight of 321.8936. It can be seen from this measurement that the detection level for 2,3,7,8-tetrachlorinated dibenzo-p-dioxin is limited by the noise generated by other ions passing through the collector slot, some of which are compounds, which have the same nominal mass as the analyte. It can be seen in this example that the level of detection is limited to about 1 fg (3 attomoles).

A preferred embodiment of the present invention will now be described with reference to FIG 4 and 5 described. A mass spectrometer in accordance with the preferred embodiment comprises a split ion detector 11 with two or more separate detectors 14a . 14b that are associated with a single collector slot 3 are provided (see 5 ). Ions from the single collector slot 3 are allowed to pass into the split ion detector 11 and are made by a reflective electrode 13 , depending on the position of the ions and the direction in which the ions move, in the direction of the mass dispersion on one side or the other side of the reflective electrode 13 divided up. The one from the reflective electrode 13 reflected ions are directed to one of two or more detectors 14a . 14b directed.

An ion beam that spreads evenly over the collector slot 3 is distributed and / or symmetrically around the center of the collector slot 3 is substantially equally divided so that substantially half of the ions in the ion beam from the reflective electrode 13 is reflected so that it is on one of the detectors 14a . 14b fall while the other half of the ions in the ion beam fall onto the reflective electrode 13 is reflected so that it is on the other detector 14a . 14b fall. Conversely, an ion beam that is not uniform across the collector slot 3 is distributed and / or not symmetrical about the center of the collector slot 3 is distributed from the electrode 13 divided unevenly so that the signals from the two detectors 14a . 14b are significantly different.

According to the preferred embodiment, the collector slot is 3 precisely positioned so that only analyte ions of interest are evenly distributed over the collector slot 3 be distributed and / or symmetrical around the center of the collector slot 3 be distributed. Accordingly, only analyte ions of interest become uniform and / or symmetrical about the reflective electrode 13 distributed so that essentially 50% of the analyte ions of interest to one of the detectors 14a . 14b fall while essentially 50% of the analyte ions fall on the other detector 14a . 14b fall. However, interference ions run through the magnetic sector mass analyzer on somewhat different trajectories and therefore do not become uniform or symmetrical over the collector slot 3 distributed. Accordingly, the interference ions do not become uniform or symmetrical about the reflective electrode 13 distributed so that the interference ions between the two detectors 14a . 14b not be distributed equally. It follows, therefore, that the ion signals from the two detectors 14a . 14b are significantly different. It is therefore by measuring the relative intensity of the signals from the two detectors 14a . 14b possible to determine whether the total ion beam passes through the collector slot 3 is evenly distributed and / or whether the ion beam is around the center of the collector slot 3 is distributed symmetrically. This in turn enables a determination to be made as to whether the detected ion beam has a significant proportion of interference ions. If the signals from the two ion detectors 14a . 14b are substantially identical, they can be summed and recorded, and the signals can otherwise be ignored or discarded. Alternatively, the signals from the two ion detectors can be summed and multiplied by a weight factor, preferably in the form exp (-ky ⁿ ), where k is preferably 1, n is preferably 2 and y is the standard deviation of the total number of the first and the first second detector during a time t is detected ions. The weighting factor preferably has the effect of maintaining the meaning of the summed signals if the signals are substantially similar and of weakening or otherwise suppressing the meaning of the summed signals if the signals differ considerably in intensity.

The reflective electrode 13 preferably includes a sheet electrode with a fine edge or a wedge-shaped electrode. The reflective electrode 13 is preferably substantially perpendicular to the plane of the collector slot 3 and arranged substantially parallel to the direction of the magnetic fields so that it divides the ion beam in the direction of the mass dispersion. The ion beam is preferably divided into two separate ion beams, which are then on two or more detectors 14a . 14b be judged. A high voltage with respect to the ion source is preferably applied to the reflective electrode 13 applied so that ions from the reflective electrode 13 are repelled and depending on which side of the dead center of the leaf electrode 13 the ions are located and directed, bounce to one or the other side. Setting the ion beam and / or the reflective electrode 13 is preferably possible so that the ion beam is centered on the collector slot 3 can be aligned and the ions in the center of the ion beam exactly on the beam splitter edge of the reflective electrode 13 be judged. All ions in the shared ion detector 11 run, are preferred to one or the other side of the reflective electrode 13 deflected so that the ions from two or more detectors 14a . 14b can be detected.

Ions preferably pass through a shielding tube 12 (as in 4 is shown) in the divided ion detector 11 and come out of the shield tube 12 out so that it is the reflective electrode 13 preferably face directly. The shield tube 12 preferably causes at least a partial and preferably considerable shielding of those by the divided ion detector 11 running ions in front of any electrical fields resulting from voltages applied to the detectors 14a . 14b be created. The one from the reflective electrode 13 Delayed electric fields generated cause the ions to bounce off and to the two or more detectors 14a . 14b be reflected back on both sides of the shield tube 12 are arranged. The two detectors 14a . 14b preferably have microchannel plates with anodes which are arranged behind the microchannel plates. Each ion that arrives at one of the microchannel plates results in the generation of an ion pulse which is emitted so that the electrons are received on the anode behind the microchannel plate. Each ion pulse that falls on the anode can be counted or integrated and then measured using an analog-to-digital converter. The ion detectors 14a . 14b may have discrete dynode electron multipliers or continuous dynode channeltrons, as described in more detail below.

5 shows in more detail the section of the mass spectrometer between the collector slot 3 and the split ion detector 11 according to an embodiment of the present invention. A lens 9 is preferably downstream of the collector slot 3 and upstream of the split ion detector 11 provided. The Lens 9 refocuses the image of the collector slot 3 preferably on the input of the split ion detector 11 , Preferably the refocused image of the collector slot 3 magnified to increase the spatial distribution of ions through the collector slot 3 run and on the shared ion detector 11 arrive.

6 shows a particularly preferred embodiment of the present invention, wherein of the reflective electrode 13 reflected ions to two conversion dynodes 15a . 15b and be accelerated towards this. Ions on the conversion dynodes 15a . 15b fall, cause the conversion dynodes 15a . 15b Generate secondary electrons. The resulting secondary electrons are then measured using two detectors 14a . 14b detected, which preferably include microchannel plate ion detectors. An advantage of using conversion dynodes 15a . 15b To initially detect the ions in place of the microchannel plates is that the effectiveness of the ion detection can be increased to almost 100%. A microchannel plate typically has an effective ion receiving area of 60-70%, on which an incident ion leads to the generation of secondary electrons. Hence the ion detection effectiveness of a microchannel plate effectively limited to around 60 - 70%. In contrast, the conversion dynodes 15a . 15b an ion detection efficiency of approximately 100% and typically deliver between two and six electrons each on the respective conversion dynode 15a . 15b incident ion. Accordingly, the probability that the like in 6 shown arranged micro-channel plates 14a . 14b at least one of the secondary electrons is detected, which is responsive to the presence of an ion on the conversion dynode 15a . 15b occurs from the conversion dynodes 15a . 15b is generated and released, practically 100%.

According to another less preferred embodiment, ions can be from the conversion dynodes 15a . 15b are accelerated and received on one or more scintillators and / or one or more phosphors (not shown). The resulting photons can then preferably be detected using one or more photo electron multiplier tubes ("PMT") and / or one or more photosensitive solid state detectors (not shown).

7 shows a further embodiment, wherein two detectors 14a . 14c respectively. 14b . 14d on each side of the reflective electrode 13 are arranged so that a total of four ion detectors are provided. According to this embodiment, part of the ion beam is directed to one side of the central reflective electrode 13 is deflected on two ion detectors 14a . 14c receive. Similarly, the one on the other side of the central reflective electrode 13 deflected part of the ion beam on two other detectors 14b . 14d receive. This embodiment enables asymmetry of the ion beam with respect to the reflective electrode 13 (and thus the collector slot 3 ) is determined more precisely. It is contemplated that six, eight, ten, twelve, or another number of other ion detectors may be provided in accordance with other embodiments not shown.

8th shows a further embodiment, the preferred split ion detector 11 downstream of a second detector system 16 . 17 . 18 is provided. The second detector system 16 . 17 . 18 is preferably provided outside the axis of the ion beam so that neutral particles in the ion beam preferably the second detector system 16 . 17 . 18 do not bother.

According to this embodiment, the upstream ion detector preferably has a conversion dynode 16 , one or more focusing ring electrodes 17 , a scintillator (or a phosphor) and a photoelectron multiplier 18 on. When the voltages applied to the second detector system are switched off, the ions pass directly past the second detector system without interruption onto the preferred split ion detector 11 , When the voltages applied to the second detector system are turned on, ions are preferentially applied to the conversion dynode 16 distracted. Ions fall on the conversion dynode 16 and cause secondary electrons to be triggered, which are then preferably triggered by the one or more ring lenses 17 on the scintillator or phosphor 18 be accelerated and focused. Alternatively, the ions can be deflected directly onto a microchannel plate detector (not shown).

According to an alternative embodiment, the preferred divided ion detector 11 and the second detection system 16 . 17 . 18 are arranged so that ions are directed onto one or the other of the two detectors by an electrostatic and / or magnetic field.

According to a further embodiment, essentially all ions can be applied to one of the detectors by an electrical and / or magnetic field in an operating mode 14a . 14b . 14c . 14d of the preferred split ion detector 11 be judged.

When an ion beam that has ions with a specific mass-to-charge ratio passes over the collector slot 3 is scanned, the resulting signal profile is commonly referred to as the detector profile. When the ion beam passes through the collector slot 3 is scanned, ions begin to be passed to the ion detector when the front edge of the ion beam reaches the first edge of the collector slot 3 reached. Ions then continue through the collector slot 3 and transmitted to the ion detector until the rear edge of the ion beam at the second opposite edge of the collector slot 3 arrives. Accordingly, the width of the tip profile is the width w _{b of} the ion beam summed with the width w _{c of} the collector slot. If the width wb of the ion beam is substantially equal to the width w _{c of} the collector slot 3 the peak profile has a maximum corresponding to the case in which the ion beam is symmetrical about the center of the collector slot 3 is distributed. The tip profile changes depending on the relative width w _{b of} the ion beam and the width w _{c of} the collector slot 3 , The peak profile also changes depending on the intensity profile of the ion beam.

High resolution recordings of selected ions, as described above for the detection of traces of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin, are commonly performed at a mass resolution of 10,000 (10% valley definition). A mass peak with a width of 100 ppm of the mass, when measured at 5 of the maximum intensity, has a mass resolution of 10000 (10% valley definition). A mass peak that is 100 ppm wide usually has maximum transmission when the collector slot width w _{c is} just equal to that of the ion beam width w _b , ie when the collector slot 3 and the ion beam each have a width of 50 ppm. Under these conditions, the source slot width w _{s is} as large as it can be, so that the collector slot 3 just the whole at the collector slot 3 transmits incoming beam and thus the peak width (w _b + w _c ) is 100 ppm.

9 shows an example of the tip profile P, which is obtained when an ion beam B with a width w _b of 50 ppm over a collector slot 3 is scanned with a width w _c of 50 ppm. The resulting observed peak profile P has a width of 100 ppm and has a maximum corresponding to the case where the ion beam is at the collector slot 3 is centered. The ion beam profile B is at one at the collector slot 3 centered position. The ion beam profile B can change according to a number of parameters in the construction of the mass spectrometer, although a typical beam profile can follow a cosine distribution. In the in 9 In the illustrated example, the ion beam profile B has a cosine distribution, and the resulting observed peak profile P, which is detected by a conventional single ion detector, has a cosine square distribution.

In high-resolution recording experiments of selected ions, the ion beam is switched to a central position at which essentially 100% of the ion beam is transmitted through a collector slit of the mass spectrometer. Because the ion beam is not scanned through the collector slot, this method does not allow knowledge of the tip profile to be obtained. It can only be assumed that the peak profile is the one that is represented, for example, by P in 9 is shown. If the tip profile is not the expected one, for example because the tip does not have the correct mass-to-charge ratio or because the tip has the measurement of randomly scattered ions with very slightly different mass-to-charge ratios, this is not known and the interference ions are included in the measurement of the analyte ions. However, if the ion beam transmitted through the collector slot is split into two or more ion beams that are detected on two or more detectors, as is the case with the preferred embodiment, the situation is quite different, as will be shown in more detail below.

10 shows an example of the peak profiles P ₁ , P ₂ , P _sum , which are observed when an ion beam with a profile B and a width w _b of 50 ppm on a collector slot 3 falls with a width w _c of 50 ppm and using a split ion detector 11 is detected according to the preferred embodiment. Those on the two detectors of the preferred split ion detector 11 The resulting peak profiles P ₁ , P ₂ are each 75 ppm wide and shifted by 25 ppm from one another. If the two peak profiles P ₁ , P _{2 are} summed, the resulting peak profile P _{sum is} 100 ppm wide and is essentially the same profile as that recorded on a conventional single ion detector as in FIG 9 is shown.

In the case of a high-resolution recording experiment of selected ions, in which the ion beam is switched to the central position, this is on each of the two detectors of the preferred split ion detector 11 The recorded ion signal is essentially the same, provided that the ion beam is around the center of the collector slot 3 is arranged symmetrically. However, if the peak profile is not as expected because, for example, the ions include scattered interference ions with slightly different mass-to-charge ratios or because the ions include randomly scattered ions with similar mass-to-charge ratios, those of the two detectors are the preferred split ion detector 11 not detected ion signals immediately. Therefore, the split ion detector enables 11 according to the preferred embodiment, a determination of whether (and indeed to what extent) interference ions are detected together with the desired analyte ions, and therefore whether the ion signal is reliable. If the ion beam is also substantially free from the presence of interference ions, the ion signals from the two detectors are essentially the same and it can be concluded with a high degree of certainty that the intended analyte ions are detected without undesired interference ions measuring the intensity of the Affect analyte ions.

It is based on 10 it can be seen that when the ion beam is switched to the central position, each detector of the preferred split ion detector 11 did not detect the maximum number of ions that it would detect if the ion beam were shifted by 12.5 ppm. The ion beam is therefore not at the top of the two detectors of the preferred split ion detector 11 arranged, even if it is arranged at the top of the peak profile P _sum for the sum of the peak profiles P ₁ , P _{2 of} the individual detectors. This means that a very small shift in the position of the ion beam causes the signal on one of the detectors to increase while the signal on the other detector decreases at the same time. Therefore, the preferred split ion detector 11 very sensitive to small shifts in the position of the ion beam and the presence of interference ions.

The effect of a small shift in the position of the ion beam is further related to FIG 11 shown. It is used in the 11 shown table assumed that the resolution of the preferred ion detector 11 Is 10,000 (10% valley definition) and that only 20 ions from the collector slot 3 be allowed through and subsequently from the preferred split ion detector 11 can be detected. In this illustration, the ion beam and the collector slot have 3 both 50 ppm wide, resulting in an observed peak profile width of 100 ppm.

In column 1 of 11 A series of shifts in the ion beam away from the center of the collector slot is tabulated in ppm units. In column 2 the corresponding ion numbers are arranged in a table, those on the first detector of the preferred divided ion detector 11 for the corresponding shift in the ion beam, detailed in column 1 is indicated, would be detected. In column 3 similarly, the number of ions that are detected on the second detector is tabulated for the same corresponding shift in the ion beam.

In column 4 is the total number of ions detected by the first and second detector, ie the sum of the columns 2 and 3 , arranged in a table. It can be seen that the total number of ions detected decreases as the position of the ion beam is increasingly shifted from the center. This is because the ion beam and the collector slot 3 have the same width and that when the ion beam is moved away from the center, not all ions in the ion beam hit the collector slot 3 fall and therefore not all ions are passed on.

In column 5 tabulates the average number of ions that would have been expected to be detected on each of the first and second detectors if the ion beam were in view of the column 4 specified total ion count in the center. In other words there is column 5 for each value of the ion beam shift simply half the total number of ions in column 4 are specified. In column 6 Tabulates a standard deviation for the expected ion count for each of the first and second detectors, which is in column 5 is specified.

In column 7 is the difference between that in column 2 specified actual number of ions for the first detector and the number of ions by column 5 would have been expected, expressed by the number of standard deviations in the column 6 expected number of ions, tabulated. In column 8th is similarly the difference, expressed in standard deviations, between that in column 3 given actual number of ions for the second detector, and that in column 5 specified expected number, again expressed by the in column 6 Number of standard deviations of the expected number of ions in a table, arranged in a table.

In column 9 the percentage probability P1 for the difference in the number of ions from the expected average is tabulated, which is less than or equal to the actual difference for the first detector in the column 7 specified number of ions assuming a natural distribution or Gaussian distribution. Likewise, in column 10 the same percentage probability P2 for the difference that for the second detector in column 8th specified number of ions arranged in a table. Therefore, in the columns 9 and 10 the percentage probabilities for observing measurements within those in the columns 7 respectively. 8th Relative standard deviations indicated, where an ion beam with the in column 4 specified number of electrons is centered on the collector slot. Finally in column 11 the combined percentage probability P for both observing a measurement outside of that in column 7 specified relative standard deviation as well as a measurement outside of that in column 8th specified relative standard deviation arranged in a table. In other words, in column 11 the percentage probability of observing the two ion numbers recorded on the first detector and the second detector for a peak with a total ion number equal to the sum of the two separate ion numbers which is centrally positioned.

How out 11 it can be seen that the ion numbers on the two detectors correspond to an ion beam which has only 20 ions, the ion beam being shifted by only 5 ppm, such that the probability that the observed ion numbers can be observed if the ion beam is centrally positioned , only about 13%. Furthermore, the ion numbers on the two detectors of an ion beam that has only 20 ions, the ion beam being shifted by 10 ppm, are such that the probability that the observed ion numbers can be observed if the ion beam is centrally positioned is only 1 %. Similarly, if the ion beam is shifted by 15 ppm, the probability that the observed ion numbers will be observed if the ion beam is centrally positioned is only 0.1%.

It is obvious in this example that the Advantage of using a split ion detector according to the preferred embodiment is that for the measurement of an ion beam with only 20 ions with a certainty of 99% guaranteed could be that the observed mass peak is not a disturbing peak that points to it is due that the Ion beam is shifted by only 10 ppm. Alternatively, you could use one 99.9% security guaranteed be that the observed mass peak is not a disturbing mass peak that is due to that the Ion beam is shifted by 15 ppm.

On the other hand, if a conventional ion detector were used, it would be necessary to use a Mass peak width to work at 5% of the height of about 20 ppm to get the same specification. This would correspond to a very high resolution of about 50,000 (10% valley definition) as opposed to 10,000 in the preferred embodiment. It can therefore be seen in this example that the split ion detector according to the preferred embodiment provides approximately a five-fold increase in specificity compared to a comparable conventional ion detector.

Alternatively, the preferred split one Ion detector viewed as providing the same specificity but is between 5 and 25 times more sensitive, because this is the likely loss of sensitivity that is out of a five-fold increase the dissolution of the mass spectrometer from 10,000 to 50,000 (10% valley definition).

12 Figure 4 shows another example of the effect of small shifts in the position of an ion beam falling on a preferred ion detector. The resolution of the preferred ion detector was reduced to 2000 in this example (10% valley definition). It was therefore assumed that the transmission had been increased by a factor of five, so that the total number of ions detected by the preferred shared ion detector rose to 100. In this representation, the width of the ion beam and the width of the collector slot are 3 both 250 ppm, resulting in a peak width of 500 ppm. It is based on 12 it will be seen that the number of ions on the two detectors resulting from the fact that the ion beam is shifted 20 ppm from the center is such that the likelihood that the observed number of ions could be observed if the ion beam was central on the collector slot was positioned, is only 1. This example illustrates the advantage of using a split ion detector according to the preferred embodiment, because for the measurement of a peak corresponding to 100 ions at a resolution of 2000 (10% valley definition) it could be ensured with a certainty of 99 that the peak was not reduced by only 20 ppm shifted disturbing peak is. On the other hand, using a conventional ion detector, it would be necessary to work with a peak width at 5% of the height of 40 ppm in order to achieve the same specificity. This corresponds to a high resolution of 25000 (10% valley definition) compared to a resolution of only 2000 according to the preferred embodiment. It also follows that the preferred split ion detector has both increased sensitivity and specificity compared to that achievable with a conventional ion detector operating at 10,000 (10% valley definition) resolution.

It was shown that the shared Ion detector according to the preferred one embodiment either the specificity improve mass analysis without loss of sensitivity can or improved sensitivity without loss of specificity can provide or actually both improved sensitivity and improved specificity can provide. Can continue fortuitously scattered ions representing background noise, at least in part, if not to a significant extent be eliminated.

Although the present invention with respect to preferred embodiments Those skilled in the art will understand that various changes can be made to the shape and details without of that in the appended claims set out scope of the invention.

Claims (72)

Magnetic sector mass spectrometer with: one Magnetic sector mass analyzer, a collector slot that downstream of the magnetic sector mass analyzer is arranged a device downstream of the Collector slot is arranged to one of the collector slot transmitted ion beam into at least a first and a first to disassemble the second ion beam, a first detector for Measure the intensity at least part of the first ion beam and a second At least detector for measuring the intensity part of the second ion beam. Magnetic sector mass spectrometer according to claim 1, wherein the ion beam has a first and a second direction, that are orthogonal to each other. Magnetic sector mass spectrometer according to claim 2, where ions in the ion beam according to their mass-to-charge ratio in dispersed in the first direction, so that the mass-to-charge ratio of Ions in the ion beam change along the first direction. Magnetic sector mass spectrometer according to claim 2 or 3, with ions in the ion beam essentially not corresponding their mass-to-charge ratio be dispersed in the second direction so that the mass-to-charge ratio of the ions in the ion beam along the second direction substantially is constant. Magnetic sector mass spectrometer according to one of the preceding Expectations, wherein the first and second detectors use intensities of at least a portion of the first and second ion beams in the measure essentially at the same time. Magnetic sector mass spectrometer according to one of the preceding Expectations, the magnetic sector mass spectrometer being a single focusing Magnetic sector mass spectrometer. Magnetic sector mass spectrometer according to one of claims 1 to 5, wherein the magnetic sector mass spectrometer is a double focusing magnetic sector mass spectrometer includes. Magnetic sector mass spectrometer according to one of the preceding Expectations, the device having an electrode which causes ions to accumulate the first and the second detector are reflected or deflected. Magnetic sector mass spectrometer according to claim 8, the electrode having a sheet with a fine edge. Magnetic sector mass spectrometer according to claim 8 or 9, the electrode including a wedge-shaped electrode. Magnetic sector mass spectrometer according to claim 8, 9 or 10, wherein the electrode has an edge and wherein at of using it care is taken that analyte ions substantially uniform and / or in the ion beam approaching the edge be arranged symmetrically with respect to the edge. Magnetic sector mass spectrometer according to one of claims 8 to 11, each electrode having an edge and being provided in use that interference ions substantially uneven and / or in the ion beam approaching the edge be arranged asymmetrically with respect to the edge. Magnetic sector mass spectrometer according to one of the preceding Expectations, which further has an electron impact ion source ("EI ion source"). Magnetic sector mass spectrometer according to one of claims 1 to 12, which further has an ion source with chemical ionization (“CI ion source”). Magnetic sector mass spectrometer according to one of claims 1 to 12, which further comprises an ion source, which follows from the following Group selected is: (i) an electrospray ion source ("ESI ion source"), (ii) an atmospheric pressure ion source with chemical ionization ("APCI ion source"), (iii) an atmospheric pressure photo ionization ion source ("APPI ion source"), (iv) a matrix-assisted laser desorption ionization ion source ("MALDI ion source"), (v) a laser desorption ionization ion source ("LDI ion source"), (vi) an inductive one coupled plasma ion source ("ICP ion source"), (vii) an ion source with rapid atomic bombardment ("FAB ion source"), (viii) a liquid secondary ion mass spectrometry ion source ("LSIMS ion source"), (ix) a field ionization ion source ("FI ion source") and (x) a field desorption ion source ( "FD") ion source. Magnetic sector mass spectrometer according to one of the preceding Expectations, which further has a continuous ion source. Magnetic sector mass spectrometer according to one of claims 1 to 15, which further has a pulsed ion source. Magnetic sector mass spectrometer according to one of claims 13 to 17, wherein when used a voltage difference between the Device and the ion source is maintained, which from the selected the following group is: (i) 0 - 100 V, (ii) 100-200 V, (iii) 200-300 V, (iv) 300-400 V, (v) 400-500 V, (vi) 500-600 V, (vii) 600-700 V, (viii) 700-800 V, (ix) 800-900 V, (x) 900-1000 V and (xi)> 1000 V. Magnetic sector mass spectrometer according to one of the preceding Expectations, which further comprises a processor, the processor being at use intensity at least a portion of the first ion beam with respect to the intensity defines at least part of the second ion beam. Magnetic sector mass spectrometer according to one of the preceding Expectations, being when the intensity at least part of the first ion beam by ≥ x% of the intensity distinguishes at least a part of the second ion beam will that the Ion beam has a significant proportion of interference ions, where x is selected from the following group: (i) 1, (ii) 2, (iii) 3, (iv) 4, (v) 5, (vi) 6, (vii) 7, (viii) 8, (ix) 9, (x) 10, (xi) 15, (xii) 20, (xiii) 25, (xiv) 30, (xv) 35, (xvi) 40, (xvii) 45, (xviii) 50, (xix) 55, (xx) 60, (xxi) 65, (xxii) 70, (xxiii) 75, (xxiv) 80, (xxv) 85, (xxvi) 90, (xxvii) 95, (xxviii) 100 and (xxix)> 100. Magnetic sector mass spectrometer according to one of the preceding claims, wherein if the intensity of at least a part of the second ion beam differs by ≥ x% from the intensity of at least a part of the first ion beam, it is determined that the ion beam has a significant proportion of interference ions, wherein x is selected from the following group: (i) 1, (ii) 2, (iii) 3, (iv) 4, (v) 5, (vi) 6, (vii) 7, (viii) 8, (ix ) 9, (x) 10, (xi) 15, (xii) 20, (xiii) 25, (xiv) 30, (xv) 35, (xvi) 40, (xvii) 45, (xviii) 50, (xix) 55, (xx) 60, (xxi) 65, (xxii) 70, (xxiii) 75, (xxiv) 80, (xxv) 85, (xxvi) 90, (xxvii) 95, (xxviii) 100 and (xxix)> 100. Magnetic sector mass spectrometer according to one of the above Expectations, where if within a time t the number of times from the first detector of the number of ions detected by the second detector Ions around ≥ y Standard deviations of the total number of the first and second Detector during the time t detected ions is determined, that the Ion beam has a significant proportion of interference ions, where y is selected from the following group: (i) 0.25, (ii) 0.5, (iii) 0.75, (iv) 1.0, (v) 1.25, (vi) 1.5, (vii) 1.75, (viii) 2.0, (ix) 2.25, (x) 2.5, (xi) 2.75, (xii) 3.0, (xiii) 3.25, (xiv) 3.5, (xv) 3.75, (xvi) 4.0 and (xvii)> 4.0. Magnetic sector mass spectrometer according to one of the preceding Expectations, where signals from the first and second detectors are summed, to produce a combined signal, and wherein the combined Signal is multiplied by a weight factor. Magnetic sector mass spectrometer according to claim 23, where the weight factor: (i) the combined signal is not significantly weakened when the signal from the first detector is substantially the same as the signal from second detector is the same, and / or (ii) the combined signal significantly weakened when the signal from the first detector differs significantly from the signal from second detector differs. The magnetic sector mass spectrometer according to claim 23 or 24, wherein the weight factor is of the form exp (-ky ⁿ ), where k and n are constants, and wherein within a time t the number of ions detected by the first detector is different from the number of ions by the second Detects detected ions by y standard deviations of the total number of ions detected by the first and second detectors during time t. Magnetic sector mass spectrometer according to claim 25, where k is selected from the following group: (i) 0.5-2.0, (ii) 0.6 - 1.8, (iii) 0.7-1.6, (iv) 0.8 - 1.4, (v) 0.9-1.2, (vi) 0.95-1.1 and (vii) 1. Magnetic sector mass spectrometer according to claim 25 or 26, where n is selected from the following group: (i) 1.0-3.0, (ii) 1.2 - 2.8, (iii) 1.4-2.6, (iv) 1.6-2.4, (v) 1.8 - 2.2, (vi) 1.9 - 2.1 and (vii) 2. Magnetic sector mass spectrometer according to one of the preceding Expectations, wherein if it is determined that the ion beam is a significant proportion of interference ions, signals from the first and / or from the second Detector discarded or otherwise considered to be relatively inaccurate become. Magnetic sector mass spectrometer according to one of the preceding Expectations, if it is determined that the ion beam is not a significant fraction of interference ions, signals from the first and second Detector are summed or otherwise considered relatively accurate become. Magnetic sector mass spectrometer according to one of the above Expectations, which continues a downstream of the collector slot arranged lens. Magnetic sector mass spectrometer according to claim 30, the lens taking the image of the collector slot onto the device refocused. Magnetic sector mass spectrometer according to claim 30, the lens substantially collimating the ion beam. Magnetic sector mass spectrometer according to one of the preceding Expectations, which further includes a shield tube for guiding ions to the device having. Magnetic sector mass spectrometer according to claim 33, the shielding tube between the collector slot and the Device is arranged. A magnetic sector mass spectrometer according to claim 33 or 34, the shield tube facing the ion beam to the shields voltages applied to the first and / or the second detector. Magnetic sector mass spectrometer according to one of the preceding Expectations, the first detector being one, two, three, four, five, six, seven, eight, nine, ten or more than ten microchannel plate detectors having. Magnetic sector mass spectrometer according to one of the preceding Expectations, the first detector being one, two, three, four, five, six, seven, eight, nine, ten or more than ten conversion dynodes to Generating electrons in response to ions being converted to the conversion dynode (s) fall. Magnetic sector mass spectrometer according to claim 37, which further one or more electron multipliers and / or one or more microchannel plate detectors for detection generated by the conversion dynode or by the conversion dynodes Has electrons. Magnetic sector mass spectrometer according to claim 37, which further one or more scintillators and / or one or has several phosphors, of which the conversion dynode or received electrons generated by the conversion dynodes in use are, and wherein the one or more scintillators and / or the one or more phosphors in response to receiving generate photons from electrons. Magnetic sector mass spectrometer according to claim 39, which further one or more photomultiplier tubes and / or one or more photosensitive solid-state detectors for detection which has photons. Magnetic sector mass spectrometer according to one of the preceding Expectations, the second detector being one, two, three, four, five, six, seven, eight, nine, ten or more than ten microchannel plate detectors having. Magnetic sector mass spectrometer according to one of the preceding Expectations, the second detector being one, two, three, four, five, six, seven, eight, nine, ten or more than ten conversion dynodes to Generating electrons in response to ions being converted to the conversion dynode (s) fall. A magnetic sector mass spectrometer according to claim 42, which further one or more electron multipliers and / or one or more microchannel plate detectors for detection generated by the conversion dynode or the conversion dynodes Has electrons. A magnetic sector mass spectrometer according to claim 42, which further one or more scintillators and / or one or more phosphors on which the conversion dynode or the conversion dynodes generated electrons in use are received, the one or more scintillators and / or the one or more phosphors responsive to receiving electrons generate photons. Magnetic sector mass spectrometer according to claim 44, which further one or more photomultiplier tubes and / or one or more photosensitive solid-state detectors for detection which has photons. Magnetic sector mass spectrometer according to one of the preceding Expectations, which further an additional Has detector that is upstream of the first and the second detector is arranged. Magnetic sector mass spectrometer according to claim 46, being the additional Detector has a conversion dynode. Magnetic sector mass spectrometer according to claim 47, wherein in an operating mode at least part of an ion beam distracted from the conversion dynode and responsive to the conversion dynode then electrons are generated. Magnetic sector mass spectrometer according to claim 48, which further one or more electron multipliers and / or one or more microchannel plate detectors for receiving the conversion dynode of generated electrons. Magnetic sector mass spectrometer according to claim 48, which further one or more scintillators and / or one or more phosphors on which the conversion dynode generated electrons are received in use, the one or more scintillators and / or the one or more multiple phosphors in response to receiving electrons Generate photons. Magnetic sector mass spectrometer according to claim 50, which further one or more photomultiplier tubes and / or one or more photosensitive solid-state detectors for detection which has photons. Magnetic sector mass spectrometer according to one of the preceding Expectations, being the reinforcement of the first and / or the second detector can be set independently. Magnetic sector mass spectrometer according to claim 52, the first and second detectors being independently adjustable Power supplies are fed. Magnetic sector mass spectrometer according to one of the preceding Expectations, wherein the first and second detectors further include one or more analog-to-digital converters and / or have one or more ion count detectors. Magnetic sector mass spectrometer according to one of the preceding Expectations, which further adjustment means for centering the ion beam of the device. Magnetic sector mass spectrometer according to claim 55, wherein the adjusting means at least one deflection electrode downstream of the Have collector slot, wherein the deflection electrode is set up for this is to move the ion beam with respect to the device. Method of mass spectrometry with the following steps: Passing an ion beam through a magnetic sector mass analyzer and a downstream of the Magnetic sector mass analyzer arranged collector slot, Splitting the ion beam downstream of the Collector slot in at least a first and a second Ion beam, Measure the intensity of at least a portion of the first ion beam with a first detector and Measure the intensity at least part of the second ion beam with a second Detector. A method for mass spectrometry according to claim 57, in which the ion beam has a first direction and a second orthogonal direction. A method for mass spectrometry according to claim 58, in which ions in the ion beam according to their mass-to-charge ratio in be dispersed in the first direction, so that the mass-to-charge ratio of the Ions in the ion beam change along the first direction. A method for mass spectrometry according to claim 58 or 59, in which ions are essentially not in the ion beam according to their mass-to-charge ratio in the second direction be dispersed so that the Mass-to-charge ratio of the Ions in the ion beam along the second direction substantially is constant. Method for mass spectrometry according to one of the Expectations 57 to 60, when using the first and second detectors the intensities at least a portion of the first and second ion beams in the measure essentially simultaneously. Method for mass spectrometry according to one of the Expectations 57 to 61, in which the intensity of at least part of the first ion beam with respect to the intensity of at least a portion of the second ion beam is determined. Method for mass spectrometry according to one of the Expectations 57 to 62, in which when the intensity of at least part of the first ion beam by ≥ x % of the intensity distinguishes at least a part of the second ion beam will that the Ion beam has a significant proportion of interference ions, where x is selected from the following group: (i) 1, (ii) 2, (iii) 3, (iv) 4, (v) 5, (vi) 6, (vii) 7, (viii) 8, (ix) 9, (x) 10, (xi) 15, (xii) 20, (xiii) 25, (xiv) 30, (xv) 35, (xvi) 40, (xvii) 45, (xviii) 50, (xix) 55, (xx) 60, (xxi) 65, (xxii) 70, (xxiii) 75, (xxiv) 80, (xxv) 85, (xxvi) 90, (xxvii) 95, (xxviii) 100 and (xxix)> 100. Method for mass spectrometry according to one of the Expectations 57 to 63, in which when the intensity of at least part of the second ion beam by ≥ x % of the intensity distinguishes at least a portion of the first ion beam will that the Ion beam has a significant proportion of interference ions, where x is selected from the following group: (i) 1, (ii) 2, (iii) 3, (iv) 4, (v) 5, (vi) 6, (vii) 7, (viii) 8, (ix) 9, (x) 10, (xi) 15, (xii) 20, (xiii) 25, (xiv) 30, (xv) 35, (xvi) 40, (xvii) 45, (xviii) 50, (xix) 55, (xx) 60, (xxi) 65, (xxii) 70, (xxiii) 75, (xxiv) 80, (xxv) 85, (xxvi) 90, (xxvii) 95, (xxviii) 100 and (xxix)> 100. Method for mass spectrometry according to one of the Expectations 57 to 64, in which if the number within a time t the number of ions detected by the first detector ions detected by the second detector by ≥ y standard deviations of the total number the ions detected by the first and second detectors during time t differs, it is found that the ion beam has a significant Portion of interference ions, where y is from the following Group selected is: (i) 0.25, (ii) 0.5, (iii) 0.75, (iv) 1.0, (v) 1.25, (vi) 1.5, (vii) 1.75, (viii) 2.0, (ix) 2.25, (x) 2.5, (xi) 2.75, (xii) 3.0, (xiii) 3.25, (xiv) 3.5, (xv) 3.75, (xvi) 4.0 and (xvii)> 4.0. Method for mass spectrometry according to one of the Expectations 57 to 65, where further: Signals from the first and the second Detector can be summed to produce a combined signal and multiplied the combined signal by a weight factor becomes. A method for mass spectrometry according to claim 66, where the weight factor: (i) the combined signal does not weaken significantly, when the signal from the first detector is substantially the same as the signal from second detector is the same, and / or (ii) the combined signal significantly weakened when the signal from the first detector differs significantly from the signal from second detector differs. A method of mass spectrometry according to claim 66 or 67, wherein the weight factor is of the form exp (-ky ⁿ ), where k and n are constants, and within a time t the number of ions detected by the first detector is different from the number of ions second detector detects ions by y standard deviations of the total number of ions detected by the first and by the second detector during time t. The method of mass spectrometry according to claim 68, wherein k is selected from the following group: (i) 0.5-2.0, (ii) 0.6-1.8, (iii) 0.7-1.6, (iv) 0.8-1.4, (v) 0.9-1.2, (vi) 0.95-1.1 and (vii) 1. A method for mass spectrometry according to claim 68 or 69, where n is selected from the following group: (i) 1.0-3.0, (ii) 1.2-2.8, (iii) 1.4-2.6, (iv) 1.6-2.4, (v) 1.8 - 2.2, (vi) 1.9 - 2.1 and (vii) 2. Method for mass spectrometry according to one of the Expectations 57 to 70, in which if it is found that the ion beam is a significant one Has proportion of interference ions, signals from the first and / or discarded by the second detector or otherwise as relatively inaccurate be considered. Method for mass spectrometry according to one of the Expectations 57 to 71, in which if it is determined that the ion beam is not a significant proportion of interference ions, signals from the first and second Detector are summed or otherwise considered relatively accurate become.