JP3681348B2 - 3D quadrupole mass spectrometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional quadrupole mass spectrometer, and more particularly to control of the degree of vacuum of a three-dimensional quadrupole mass spectrometer.
[0002]
[Prior art]
In a 3D quadrupole mass spectrometer (3DQMS) that performs mass analysis of ions derived from the sample, a ring electrode is placed in the insulator that keeps and fixes the 3DQ part (3D quadrupole part), and the top and bottom of the insulator An end cap electrode is disposed on the surface.
[0003]
The sample ionized in the 3DQ part or externally and introduced into the 3DQ part is held in the 3DQ part for an arbitrary time, and then released to the detector for each mass number from the pores formed in the end cap.
[0004]
An inert gas such as helium as a carrier gas or a reaction gas is constantly introduced into the 3DQ portion, and the degree of vacuum is lower than that outside the 3DQ.
[0005]
Helium used as a carrier gas has a role as a buffer gas in the 3DQ portion, and the ion retention efficiency varies depending on the amount of helium.
[0006]
The amount of ions and the amount of buffer gas in the 3DQ portion are adjusted by adjusting the amount of these introduced into the 3DQ portion.
[0007]
[Problems to be solved by the invention]
However, in the above prior art, there is a wall surrounding the side surface of the 3DQ part, so the outlet of ions in the 3DQ part is only the pores of the end cap electrode, and the exhaust efficiency is low, and a vacuum is required for cleaning and column replacement. After opening, it took a long time to start up the device again and ensure the degree of vacuum necessary for analysis.
[0008]
In 3DQMS, data is collected by repeating the operation of discharging ions introduced into the 3DQ section within an arbitrary time to the detector for each mass number by high-frequency voltage sweep.
[0009]
Therefore, it is possible to increase the sensitivity of the analysis by introducing more target ions within an arbitrary time.
[0010]
However, in the prior art, as described above, since the amount of ions and the amount of buffer gas are adjusted by adjusting the amount of these introduced into the 3DQ section, the optimum separation of a separation device such as a gas chromatograph device is performed. It was difficult to satisfy the conditions and the optimum conditions for ion detection of the mass spectrometer at the same time.
[0011]
In other words, when the gas chromatograph is an ion species separator, increasing the carrier gas flow rate can increase the amount of target ions introduced into the 3DQ unit per unit time, but increases the carrier gas flow rate. Then, helium existing in the 3DQ portion increases more than necessary, and the resolution decreases.
[0012]
In addition, when helium present in the 3DQ portion increases more than necessary, there is a problem in that an interaction between ions such as CI occurs, resulting in a mass number shift and a high-accuracy mass spectrum cannot be obtained.
[0013]
Further, when the carrier gas flow rate is increased and the degree of vacuum is lowered, the ion retention efficiency is lowered and the detection sensitivity is lowered.
[0014]
The object of the present invention is to provide the 3DQ section itself with a function of adjusting the degree of vacuum, and by this function, the degree of vacuum in the 3DQ section is controlled to shorten the apparatus start-up time. It is to realize a three-dimensional quadrupole mass spectrometer capable of performing high-sensitivity and high-precision analysis by making it possible to set the optimum conditions of the mass spectrometer at the same time.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
(1) In a three-dimensional quadrupole mass spectrometer that has a three-dimensional quadrupole portion that confines ions derived from a sample and performs mass analysis of the sample, the three-dimensional quadrupole portion is formed on the three-dimensional quadrupole portion. A three-dimensional quadruple by controlling the opening degree of the open / close control valve by providing a vent hole penetrating the inside and outside of the multipole portion and a control valve disposed in the vent hole for opening and closing the vent hole. adjust the degree of vacuum in-electrode portion.
[0016]
(2) Preferably, in the above (1), the gas introduction means for introducing the buffer gas into the three-dimensional quadrupole portion, the flow rate of the gas introduced from the gas introduction means, and the control valve are controlled. And a control means for maintaining the degree of vacuum in the three-dimensional quadrupole part at a predetermined value and adjusting sensitivity and resolution.
[0017]
(3) Preferably, in (1) above, the standard gas is introduced to detect the peak resolution and intensity, and the opening degree of the control valve is controlled based on the detected peak resolution and intensity. Set analysis conditions.
[0019]
The degree of vacuum adjustment means is provided in the three-dimensional quadrupole part, and when the apparatus is started up, the degree of vacuum required for analysis can be quickly achieved by the degree of vacuum adjustment means, and the startup time of the apparatus can be shortened.
[0020]
In addition, even if the buffer gas flow rate increases, the degree of vacuum adjustment means can be controlled to keep the inside of the three-dimensional quadrupole at the optimum degree of vacuum for analysis. And the optimum conditions of the mass spectrometer can be set simultaneously.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a three-dimensional quadrupole part (3DQ part) of a three-dimensional quadrupole mass spectrometer according to an embodiment of the present invention, where a ventilation control valve is provided on a wall surface. This is an example feature.
[0022]
FIG. 2 is a schematic configuration diagram of a gas chromatograph / mass spectrometry system using the 3DQ unit shown in FIG.
[0023]
Furthermore, FIG. 3 is an operation flowchart from starting of the apparatus by 3DQMS which is one embodiment of the present invention to determination of analysis conditions.
[0024]
First, in FIG. 2, the measurement sample is supplied to the GC column 9 of the gas chromatograph device 8, and the ionized sample is supplied to the 3DQ unit 11 of the mass spectrometer 10 and is confined for a predetermined time.
[0025]
The 3DQ portion 11 is disposed in the high vacuum portion, and this high vacuum portion is evacuated by the pump 12 and the molecular pump 13 so that the degree of vacuum is maintained.
[0026]
The ions confined in the 3DQ unit 11 for a predetermined time are supplied to the detector 14, and the data processor 15 analyzes the number of ions detected by the detector 14 to analyze the mass of the sample.
[0027]
Next, the configuration of the 3DQ unit 11 will be described with reference to FIG.
In FIG. 1, the end cap electrodes 1 and 2 and the ring electrode 3 facing each other are supported by an insulator 4.
[0028]
A buffer gas inlet 7 is formed in the insulator 4, and ions are introduced into the 3DQ portion 11 from the buffer gas (carrier gas) inlet 7 together with the carrier gas.
[0029]
The end cap electrodes 1 and 2 are formed with pores 16 which serve as ion outlets.
[0030]
A 3DQ portion vent hole 5 is formed in the insulator 4. The 3DQ portion vent hole 5 is formed so as to penetrate the inside and outside of the 3DQ portion 11, and the control valve 6 is disposed in the 3DQ portion vent hole 5.
[0031]
This control valve 6 can operate from the fully closed state to the fully opened state of the 3DQ portion vent hole 5. The vent amount of the vent hole 5 is adjusted by the degree of opening of the valve 6 from the data processing device 15 of the mass spectrometer. Controlled.
[0032]
Next, with reference to FIG. 3, the operation from the start of the apparatus by the 3DQMS of the present invention to the determination of the analysis conditions will be described.
In FIG. 3, when the power of the apparatus is turned on, the control valve 6 is fully opened, evacuation is started by the pump 12 or the like, and the start of the apparatus is completed when the inside of the 3DQ section 11 reaches a predetermined degree of vacuum. (Steps S1 to S4).
[0033]
Since the control valve 6 is fully opened at the time of starting up this apparatus, the exhaust in the 3DQ section 11 can be performed quickly, and the stabilization time of the apparatus which is the part (A) of FIG. 3 is shortened. Can be
[0034]
Next, after the degree of vacuum of the mass spectrometer becomes a condition that allows analysis, the chromatogram and the mass spectrum are monitored on the control screen of the data processing device 15 to optimize the degree of vacuum in the 3DQ unit 11.
[0035]
In other words, the degree of vacuum in the three-dimensional quadrupole portion 11 is controlled by controlling the flow rate of the gas introduced from the buffer gas inlet 7 as the gas introduction means and the opening degree of the control valve 6 as the degree of vacuum adjustment means. The predetermined values are maintained, and the sensitivity and resolution are adjusted by the data processing device 15 (which is also a control means for adjusting sensitivity and resolution) as condition setting means.
[0036]
Then, the carrier gas flow rate or the reaction gas introduction amount is set as the measurement condition for the sample to be analyzed, and a standard gas such as a calibration gas is introduced (steps S5 and S6).
[0037]
Next, the peak resolution and intensity of the standard gas are confirmed on the screen of the data processor 15, and the degree of vacuum is adjusted. That is, the degree of opening of the control valve 6 is changed, the resolution of the monitor component is fixed at a position where the peak intensity is maximum within the range determined by the measurer, and the optimal analysis condition of the mass spectrometer is determined ( Steps S7 to S9).
[0038]
And a sample is measured on the said analysis optimal conditions (step S10). This allows measurement with the best sensitivity.
[0039]
When the analysis conditions are changed and the gas introduction amount is changed, or when better data is required, the condition examination is performed again in order to obtain high sensitivity and high resolution (step S11). This ensures an optimum degree of vacuum at all times.
[0040]
In addition, it is also possible to automatically determine the analysis optimum condition regardless of the operator by forming the sequence of the operation operation flow shown in FIG.
[0041]
In this case, the optimum condition is determined using the resolution value preset by the measurer as a threshold value.
[0042]
As described above, according to the three-dimensional quadrupole mass spectrometer that is one embodiment of the present invention, the 3DQ unit 11 is provided with the vent hole 5 and the control valve 6 that changes the opening state of the vent hole 5. By fully opening the control valve 6 at the time of start-up, the degree of vacuum necessary for analysis can be quickly obtained, and the start-up time of the apparatus can be shortened.
[0043]
Further, even if the carrier gas flow rate and the reaction gas introduction amount are increased, the open / close state of the control valve 6 can be controlled and the inside of the 3DQ unit 11 can be constantly maintained at the optimum degree of vacuum for analysis. The optimum ion separation conditions and the optimum mass spectrometer conditions can be set simultaneously.
[0044]
For this reason, since the carrier gas flow rate is increased and the target component can be introduced and detected in the trap in a short time, a highly sensitive analysis of a trace component is possible.
[0045]
In addition, since a high vacuum is maintained in the 3DQ section 11, since interaction between ions such as recombination between sample ions and chemical ionization reaction can be suppressed, an accurate mass spectrum can always be obtained. .
[0046]
The above-described example is an example in which the control valve 6 is provided in the 3DQ portion 11 to adjust the degree of vacuum in the 3DQ portion 11. However, in addition to the control valve 6, for example, an introduction hole for introducing a reactive gas is further formed. In addition, the degree of vacuum in the 3DQ portion 11 can be adjusted by the reaction gas supplied from the introduction hole and the opening / closing operation of the control valve 6.
[0047]
【The invention's effect】
According to the present invention, it is possible to control the degree of vacuum in the 3DQ part of the 3DQMS, shorten the apparatus start-up time, and simultaneously set the optimum separation conditions for the separation apparatus and the optimum conditions for the mass spectrometer. By doing so, a three-dimensional quadrupole mass spectrometer capable of performing highly sensitive and highly accurate analysis can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a 3DQ portion in 3DQMS according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a gas chromatograph / mass spectrometry system using 3DQMS according to an embodiment of the present invention.
FIG. 3 is an operation flowchart from activation of an apparatus by 3DQMS according to an embodiment of the present invention to determination of analysis conditions.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 2 End cap electrode 3 Ring electrode 4 Insulator 5 3DQ part ventilation hole 6 Control valve 7 Buffer gas inlet 8 Gas chromatograph apparatus 9 GC column 10 Mass spectrometer 11 3DQ part 12 Pump 13 Molecular pump 14 Detector 15 Data processing Device 16 pore

Claims (3)

In a three-dimensional quadrupole mass spectrometer that has a three-dimensional quadrupole portion that confines ions derived from a sample and performs mass analysis of the sample,
The opening / closing control comprising: a vent hole formed in the three-dimensional quadrupole portion and penetrating the inside and outside of the three-dimensional quadrupole portion; and a control valve disposed in the vent hole for opening and closing the vent hole. three-dimensional quadrupole mass spectrometer, wherein the benzalkonium adjust the vacuum degree of the three-dimensional quadruple in-electrode unit by controlling the opening degree of the valve. The three-dimensional quadrupole mass spectrometer according to claim 1, wherein a gas introduction means for introducing a buffer gas into the three-dimensional quadrupole section, a flow rate of the gas introduced from the gas introduction means, and the control valve A three-dimensional quadrupole mass spectrometer comprising: control means for controlling and maintaining the degree of vacuum in the three-dimensional quadrupole part at a predetermined value and adjusting sensitivity and resolution. The three-dimensional quadrupole mass spectrometer according to claim 1, wherein a standard gas is introduced to detect peak resolution and intensity, and the opening degree of the control valve is controlled based on the detected peak resolution and intensity. A three-dimensional quadrupole mass spectrometer characterized by setting analysis conditions .

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