KR100816081B1 - An inductively coupled plasma mass spectrometer with an improved sensitivity by storing and concentrating ions in the reaction cell - Google Patents

Abstract

An inductively coupled plasma mass spectrometer is provided to obtain high-sensitivity analysis results of an ultramicro-element below ppq(10^-15) by concentrating ions of the element to improve concentration of the ions. An inductively coupled plasma mass spectrometer includes a plasma unit(10), an interface(20), an ion lens unit(30), a reaction cell(40), a mass analyzing unit(50), and an ion detector(60). The plasma converts a sample solution into ions. The interface extracts a required component from ion beam of the plasma unit. The ion lens unit focuses the ion beam passed through the interface. The reaction cell removes an interference component from the ions passed through the ion lens unit. The mass analyzing unit removes the remaining ions from the ions without the interference component. The ion detector detects the ions to be analyzed. Ion trap lenses(1a,1b) are installed at an inlet and an outlet of the reaction cell respectively to store and concentrate the ions with pulse voltage according to a fine time control program.

Description

An inductively coupled plasma mass spectrometer with an improved sensitivity by storing and concentrating ions in the reaction cell}

1 is a block diagram showing an example of an inductively coupled plasma mass spectrometer according to the present invention,

FIG. 2 is a graph illustrating a change in voltage applied to an inlet lens, a cell quadrupole and an outlet lens for implantation, storage and release of ions in a reaction cell.

Figure 3 is a block diagram showing a conventional inductively coupled plasma mass spectrometer.

<Code Description of Main Parts of Drawing>

1a, 1b: ion trap lens

10: plasma part

20: interface

30 ion lens unit

40: reaction cell

50: mass spectrometer

60: detector

The present invention relates to an improvement in sensitivity of an inductively coupled plasma mass spectrometer, and more particularly, to an inductively coupled plasma mass spectrometer, in which the amount of ions to be detected is increased by concentrating ions to be detected and sending them to the detector at one time. .

In general, a mass spectrometer having a plasma ion generating source is used to analyze the compositional components of a sample dissolved in a solution and is configured as shown in FIG. 3.

As shown, a conventional plasma mass spectrometer has an interface 20 for generating plasma and extracting a required component from an ion beam from the plasma portion 10 and the plasma portion 10 for ionizing a sample solution. ), An ion lens unit 30 for focusing an ion beam passing through the interface 20, a quadrupole reaction cell 40 for removing interference components from ions passing through the ion lens unit 30, Among the ions from which the interference component is removed from the reaction cell 40, the mass spectrometer 50 selectively passes only the ions to be measured, and the ion detector 60 detects the measured ions passed therethrough.

The mass spectrometer configured as described above supplies the sample to be analyzed in the state of gas, vapor or fine spray, and the supplied sample is ionized in the plasma unit 10 and supplied to the interface 20 and passed through the ion lens unit 30. Electrons and anions are filtered out, and only cations are accelerated to pass through the ion lens unit 30.

Passed cations enter the reaction cell 40 and are provided to the mass spectrometer 50 with molecular ions causing co-interference caused by collision with the cell gas removed from the mass cell 50. After removing other unnecessary ions, only the ions to be measured are sent to the detector 60 to detect the corresponding measured ions.

However, the conventional plasma mass spectrometer does not have a storage function, so that the ions are continuously supplied to the mass spectrometer and the detector so that the concentration of the measurement element in the sample, such as plutonium in the environmental sample, is less than the ppq (10 ^-15 ) level. When present, the amount of ions to be detected is so small that the accuracy and reproducibility of the detection are poor, so that accurate information cannot be obtained.

The present invention has been invented to solve the above problems, by increasing the concentration of ions that can be detected by the detector by transferring the concentration of ions to be detected to the detector high sensitivity inductively coupled plasma that can obtain accurate analysis results It is an object to provide a mass spectrometer.

Inductively coupled plasma mass spectrometer, which improves sensitivity by storing / concentrating ions in a reaction cell according to the present invention for achieving the above object, a plasma unit for generating plasma and ionizing a sample solution, and an ion beam supplied from the plasma unit an interface for extracting necessary components from a beam, an ion lens unit for focusing an ion beam passing through the interface, a reaction cell for removing interference components from ions passing through the ion lens unit, and interference in the reaction cell In the mass spectrometer comprising a mass spectrometer to remove other ions from the removed ions and an ion detector for detecting the ions to be analyzed, the ion trap lens is installed at the inlet and the outlet of the reaction cell, respectively And a pearl controlled by a fine time control program on the inlet and outlet ion trap lenses. It is characterized in that the sensitivity is improved by implanting, storing and concentrating ions by applying a voltage.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily understand and reproduce.

1 is a block diagram illustrating an example of an inductively coupled plasma mass spectrometer according to the present invention, and FIG. 2 is a diagram illustrating voltages applied to an inlet lens, a cell quadrupole, and an outlet lens for implantation, storage, and release of ions in a reaction cell. It is a graph showing the change.

As shown, the mass spectrometer according to the present invention is characterized in that the ion trap lens (1a, 1b) for limiting the emission of ions at the inlet and outlet of the reaction cell 40 is further configured.

The ion trap lenses 1a and 1b include an inlet ion trap lens 1a provided at the inlet side of the reaction cell 40 and an outlet ion trap lens 1b provided at the outlet side.

Each of the components of the present invention is generally similar to the components constituting the mass spectrometer, but will be described in detail as follows.

The mass spectrometer of the present invention includes a plasma unit 10, an interface 20, an ion lens unit 30, a reaction cell 40, a mass spectrometer 50, and ions in which plasma is generated. And a detector 60.

The plasma unit 10 is a plasma generated and used as a means for ionizing a sample solution, the interface 20 is a necessary component required for mass analysis required from the ion beam (ion beam) output from the plasma unit 20 Extracts only the ion beam, and the ion beam passing through the interface 20 is focused by the ion lens unit 30 and is focused at a central point.

Among the ions passing through the ion lens unit 30, molecular ions interfering with the analyte to be analyzed are removed from the reaction cell 40, and only the ions of the measurement element among the remaining ions are removed from the mass spectrometer 50. Optionally passed. As such, unnecessary ions are removed and only the ions of the measurement element to be analyzed are delivered to the ion detector 60 for analysis.

The present invention is configured by further installing the ion trap lens (11, 1b) at the inlet and outlet of the reaction cell 40 of the mass spectrometer configured as described above, the ion trap lens (1a, 1b) is a reaction cell 40 As in the conventional mass spectrometer, it removes molecular ions that cause interference and at the same time, it is used as a means for storing and concentrating ions in the reaction cell 40.

The ion trap lenses 1a and 1b are electrically operated to allow the mass spectrometry ions to be stored and concentrated for a while in the reaction cell 40. If a pulse voltage is applied to the inlet ion trap lens 11 and the outlet ion trap lens 1b using a fine time control program as shown in FIG. 2, ions may enter the reaction cell 40 but not exit. It is not stored under the condition that it can be stored under the condition of releasing stored ions at a time and injected into the mass spectrometer 50.

That is, in the ion implantation step, a low voltage is applied to the inlet ion trap lens 1a, and a high voltage is applied to the outlet ion trap lens 1b, thereby closing the ions to be supplied into the reaction cell 40. When ions are introduced into the reaction cell 40 after a predetermined time (a few ms) has elapsed, the ions are applied to the inlet and outlet ion trap lenses 1a and 1b so that the ions are stored in the reaction cell 40. By opening the outlet ion trap lens 1b by applying a low voltage to the outlet ion trap lens 1b only after a predetermined time, the ions are discharged in a concentrated state and provided to the ion detector 60.

In addition, the quadrupole constituting the reaction cell 40 not only increases the efficiency of removing unnecessary ions by supplying the voltage of the auxiliary waveform in addition to the existing DC voltage and RF voltage. The ions can optionally be stored and concentrated, and in the case of molecular ions, they can be dissociated.

The voltage of the auxiliary waveform applied to the quadrupole of the reaction cell 40 has a frequency of 10 kHz to 500 kHz on a 1 MHz RF waveform and has an amplitude of about 30 V.

As described in detail above, the present invention allows ion implantation, storage and release by installing ion trap lenses at the inlet and outlet of the reaction cell and opening and closing the lens by applying a pulse voltage thereto according to a minute time control program. Thus, while achieving the conventional purpose of removing the molecular ions causing interference by intercepting the entrance and exit of the ions supplied into the reaction cell with the ion trap lens, the concentrated ions are instantly stored by storing and concentrating the ions of the measurement element. By releasing to the mass spectrometer, the concentration of ions that can be detected by the detector is increased, thereby obtaining a high sensitivity analysis result of ultra trace elements of ppq or less.

While the present invention has been described with reference to the accompanying drawings, it will be apparent to those skilled in the art that many various obvious modifications are possible without departing from the scope of the invention from this description. Accordingly, the invention can only be construed limited by the words of the appended claims.

Claims (2)

Plasma is generated to pass through the interface 20 and the interface 20 for extracting the necessary components from the plasma portion 10, the ion beam from the plasma portion 20 to ionize the sample solution. The ion lens unit 30 that focuses the ion beam, the reaction cell 40 which removes the interference component among the ions passing through the ion lens unit 30, and the ions whose interference component is removed from the reaction cell 40 In the mass spectrometer comprising a mass spectrometer 50 for removing other ions remaining in the air and an ion detector 60 for detecting ions to be analyzed, Ion trap lenses 1a and 1b are installed at the inlet and the outlet of the reaction cell 40, and ions are applied to the inlet and outlet ion trap lenses 1a and 1b by applying a pulse voltage according to a fine time control program. Inductively coupled plasma mass spectrometer which improves sensitivity by storing / concentrating ions in a reaction cell, characterized by improving sensitivity by injecting, storing and concentrating. The method of claim 1, wherein by adding an auxiliary waveform having a frequency of 10 kHz to 500 kHz and having an amplitude of 30 V overlapping the 1 MHz RF waveform applied to the quadrupole of the reaction cell 40, unnecessary ions are removed and ions are selectively removed. Inductively coupled plasma mass spectrometer which improves sensitivity by storing / concentrating ions in a reaction cell, wherein the ions are stored and concentrated, and dissociate molecular ions.

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