JPH04206134A - Capillary electrophoresis mass spectrometer and analyzing method - Google Patents

Abstract

PURPOSE:To improve an S/N ratio and analyze a mass accurately by detecting the moving speed of a separated sample by an ultraviolet ray absorber, control ling the voltage applied to the opposed ends of a capillary tube according to the detection signal, and thereby controlling the moving speed of the sample. CONSTITUTION:At the time point when ultraviolet rays are detected by ultraviolet ray detector 11 installed in front of an ion source 6 according to separation components which pass therethrough, a high voltage control circuit 12 is actuated to lower the output voltage V of a high voltage source 1. The electophoresis speed of a sample is thereby lowered to extend the measurement time for the alanalysis of mass. In this case, a mass analyzer 8 is set preliminarily to meet the ion mass number of sample components to be noted. While the background spectra of electolyte other than the sample components is zero (0) in the signal of the detector 11, from the time point when the sample components to be noted are separated and the signal starts to rise, the control circuit 12 is operated to decrease an application voltage V to thereby obtain the spectra of mass.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a capillary electrophoresis mass spectrometer and an analysis method used for analyzing macromolecules.

[Prior art] Capillary zone mass spectrometry method by Smith (R,D, Sm1th) et al.
ophoresis Mass Spectrometer
y, CZ E -M S ) is shown in FIG.

Sample 3 and electrolyte 4 are heated to +30k by high voltage power supply l.
Approximately V is applied. By immersing the capillary 5 into the electrolytic solution 4, the electrolytic solution is sucked up by capillary action.

Thereafter, the sample is sucked up by immersing the capillary tube 5 into the sample 3 in the same manner. The mixed components of the electrolytic solution and sample that have been sucked up are positively ionized and migrate toward the lower voltage side due to the electric field within the tube, but the migration speed differs depending on the mobility of each component.

As described above, the analytical components migrate within the capillary tube 5 and are separated before reaching the ion source 6, where they are ionized and subjected to mass spectrometry.

[Problem to be solved by the invention] According to Smith et al., the time required for one peak to appear for each component as shown in Figure 3 is the time required for mass spectrometry in the CZE spectrum that is separated only by capillary electrophoresis. short 10
It is about seconds.

When performing mass spectrometry on each amino acid component separated by CZE, it is ideal that the concentration of the separated components remains constant during mass spectrometry.

J, W, Jorgeneson et al. (Anal,
Chew, 1981.

53.1298-1302), the velocity ν of migration in a capillary is proportional to the applied potential gradient, ν=μE=μV/L... (1) μ: Electrical mobility■・Applied voltage 9 It is expressed as the length of the capillary tube.

Further, the number of theoretical plates N, which represents the separation power of electrophoresis, is summarized by the following formula.

N=μV/2D...(2) D=diffusion coefficient of each component in the capillary From the above theoretical formula (2), high speed by capillary electrophoresis.

In order to perform high-resolution analysis, it is sufficient to increase the applied voltage V.

In order to increase the resolution as a CZE, it is better to increase the applied voltage V. On the other hand, as a mass spectrometer, in order to decrease the time rate of change of the peak of the separated components, it is necessary to decrease V.

An object of the present invention is to provide a capillary electrophoresis mass spectrometer that can satisfy the above two contradictory demands.

[Means for Solving the Problems] The present inventors have developed the CZE spectrum of Smith et al. shown in FIG.
This signal can be obtained by using an ultraviolet absorption detector in front of the ion source, but at the moment this signal rises to more than twice the noise level, the applied voltage is lowered to slow down the migration speed ν. From the above formula (1), the applied voltage is V
I realized that the width of the peak can be increased by n times by lowering the value to /n. The present invention has been made based on the above, and the gist thereof is as follows.

(1) A voltage applying means for applying a high voltage to a sample solution and an electrolytic solution, a capillary for moving the sample solution and the electrolytic solution, an electric field applying means for applying a potential difference to both ends of the capillary, and a voltage applying means for applying a high voltage to the sample solution and the electrolyte. In a capillary electrophoresis mass spectrometer comprising an ion source that ionizes components separated while the electrolytic solution moves through the capillary tube, and a means for detecting the ions, an ultraviolet absorption detector is provided in front of the ion source. Capillary electrophoresis mass spectrometry characterized by comprising a control means for detecting the moving speed of the separated sample, controlling the voltage applied to both ends of the capillary tube based on the detection signal, and controlling the moving speed of the separated sample. Device.

(2) Sample solution to which a voltage is applied by a high-voltage power supply and
.

In capillary electrophoresis mass spectrometry, components separated while an electrolytic solution is moving through a capillary by an electric field based on a potential difference between both ends of the capillary are ionized using an ion source, and mass spectrometry is performed by detecting the ions. An ultraviolet absorption detector provided at the exit of the capillary tube of the capillary electrophoresis device detects the peak of the sample component, and before the sample component reaches the ion source, the high voltage power source is controlled to lower the applied voltage, A capillary electrophoresis mass spectrometry method characterized in that the migration speed of the sample components is lowered to lengthen the measurement time for mass spectrometry.

An example of the configuration of the present invention is shown in FIG.

The difference from the conventional configuration shown in FIG. 2 is that an ultraviolet absorption detector 11 is provided in front of the ion source, and a high-voltage power supply control circuit 12 is activated when absorption of ultraviolet rays by the passing separated components is detected. Therefore, the output voltage V of the high-voltage power supply 1 is lowered.

Further, in the capillary electrophoresis mass spectrometer, when ions of the sample of interest begin to be detected by the ion detector of the mass spectrometer, the high voltage control circuit is activated;
The rate of variation in the spectral pattern may be reduced by lowering the applied voltage to slow the electrophoresis speed and lengthening the mass spectrometry time to slow the variation in sample ions.

[Function] The relationship between the applied voltage of the present invention and the CZE spectrum measured by the ultraviolet absorption detector 11 will be explained with reference to FIG.

While the signal from the detector is at the noise level, a voltage V is applied to the sample 3 and the electrolytic solution 4, and when the signal from the ultraviolet absorption detector 11 reaches a predetermined level or higher, the applied voltage is increased to V.
/n.

The CZE spectrum originally shows a sharp peak as shown in Fig. 3, but the moving speed ν in the capillary tube is
When it decreases to ν/n, it becomes a wide triangular wave as shown in FIG.

In this way, the peak width of the components separated by CZE expands by n times by lowering the accelerating voltage to V/n, and then
The ions are ionized by the ion (electron spray ion) source 6, and the analysis time in the four-electrode mass spectrometer 8 can be extended. As a result, the time rate of change for each peak of the sample during mass spectrometry can be made smaller than before.
The credibility of the quantitative analysis can be improved.

[Example] The analysis device that controls the output voltage V of the high voltage power supply 1 by the signal from the ultraviolet absorption detector 11 provided in front of the ion source 6 was described in FIG. An example is shown in FIG.

In this embodiment, an ion detector 10 is provided after the four-electrode mass spectrometer 8, and the high-voltage power supply control circuit 10 receives the output signal from the ion detector 10.
2 to control the high voltage power supply 1.

In this measurement method, the mass spectrometer 8 is adjusted in advance to the mass number of interest of the ions of the sample components. The background spectrum of the electrolytic solution other than the sample components has a signal of O from the ion detector, but when the sample component of interest is separated and the signal begins to rise, the high-voltage power supply control circuit 12 operates to apply The voltage V is lowered and a mass spectrometry spectrum is obtained.

The advantage of this method over the case of FIG. 1 is that there is less time delay between the ultraviolet absorption detector 11 and the ion detector 10.

In FIGS. 1 and 5, a four-electrode mass spectrometer is used as the mass spectrometer 8 as in the conventional case, but a double convergence type mass spectrometer that combines a magnetic field and an electric field may be used.

Incidentally, FIG. 6 shows a comparison between the capillary electrophoresis-mass spectrum of the present invention and the conventional one.

[Effects of the Invention] Conventionally, the number of samples separated during mass spectrometry increases and decreases rapidly as shown in Figure 3, and the peak pattern fluctuates greatly, especially as shown in Figure 6A. The molecular ion M having a slow velocity had a small peak intensity and was not detected in some cases.

In the present invention, since the applied voltage V is lowered at the point at which sample components appear, there is little change in the peak intensity over time as shown in Figure 4, and sufficient peak intensity of the molecular ion M can be obtained as shown in Figure 6B. , there is also little change (decrease) in the peak pattern.

In addition, the S/N ratio is high, allowing accurate mass determination.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a capillary electrophoresis mass spectrometer of the present invention,
Figure 2 is a configuration diagram of a conventional capillary electrophoresis mass spectrometer, Figure 3 is a conventional capillary electrophoresis (CZE) spectrum, and Figure 4 is a diagram of a conventional capillary electrophoresis mass spectrometer.
The figure is a diagram showing the relationship between applied voltage and CZE spectrum of the present invention, Figure 5 is a block diagram of a capillary electrophoresis mass spectrometer according to another embodiment of the present invention, and Figure 6 is a CZE-MS spectrum of the conventional and present invention. FIG. 1... High voltage power supply, 2... High voltage application part, 3...
・Sample, 4... Electrolyte solution, 5... Capillary tube, 6...
Ion source, 7... Differential pumping system, 8... 4-electrode mass spectrometer, 9... Main pumping system, 10... Ion detector, 11...
...Ultraviolet absorption detector, 12...High voltage power supply control circuit. Agent Patent attorney Akio Takaran:, (1 other person) -) Figure 3 Figure 4 'I' I hI E

Claims (1)

[Scope of Claims] 1. Voltage application means for applying a high voltage to a sample solution and an electrolyte solution, a capillary tube for moving the sample solution and the electrolyte solution, and an electric field application means for applying a potential difference to both ends of the capillary tube. , a capillary electrophoresis mass spectrometer comprising an ion source that ionizes components separated while the sample solution and the electrolytic solution are moving through the capillary tube, and a means for detecting the ions, wherein an ultraviolet ray is provided in front of the ion source. It is characterized by comprising a control means that includes an absorption detector to detect the moving speed of the separated sample, controls the voltage applied to both ends of the capillary tube based on the detection signal, and controls the moving speed of the separated sample. Capillary electrophoresis mass spectrometer. 2. Voltage application means for applying a high voltage to the sample solution and the electrolytic solution, a capillary tube for moving the sample solution and the electrolytic solution, an electric field application means for applying a potential difference to both ends of the capillary tube, and In a capillary electrophoresis mass spectrometer comprising an ion source that ionizes components separated while an electrolytic solution is moving through the capillary tube, and means for detecting the ions, an ultraviolet absorption detector is provided in front of the ion source. A capillary electrophoresis mass spectrometer, comprising: a control means that detects the moving speed of the separated sample, and uses the detection signal to lower the voltage applied to both ends of the capillary to reduce the moving speed of the separated sample. 3. Voltage applying means for applying a high voltage to the sample solution and the electrolytic solution; a capillary tube for moving the sample solution and the electrolytic solution; an electric field applying means for applying a potential difference to both ends of the capillary; In a capillary electrophoresis mass spectrometer comprising an ion source that ionizes components separated while an electrolytic solution is moving through the capillary tube, and a means for detecting the ions, an output signal from the ion detecting means is used to ionize components at both ends of the capillary tube. A capillary electrophoresis mass spectrometer characterized by comprising a control means for controlling an applied voltage and controlling a moving speed of the separated sample. 4. An ion source ionizes the separated components while the sample solution and electrolytic solution, to which a voltage is applied by a high-voltage power supply, moves through the capillary tube by an electric field based on the potential difference between the two ends of the capillary tube, and detects the ions. In capillary electrophoresis mass spectrometry, which performs mass spectrometry, an ultraviolet absorption detector installed at the outlet of a capillary tube of the capillary electrophoresis device detects a peak of a sample component, and the peak of the sample component is detected before the sample component reaches the ion source. . A capillary electrophoresis mass spectrometry method, characterized in that the high voltage power source is controlled to lower the applied voltage, the migration speed of the sample components is lowered, and the measurement time for mass spectrometry is lengthened. 5. An ion source ionizes the separated components while the sample solution and electrolytic solution, to which a voltage is applied by a high-voltage power supply, moves through the capillary tube by an electric field based on the potential difference between the two ends of the capillary tube, and detects the ions. In capillary electrophoresis mass spectrometry, which performs mass spectrometry, when ions of interest in a sample begin to be detected by an ion detector, the high-voltage power supply is controlled to lower the applied voltage to slow down the electrophoresis speed and detect ions. A capillary electrophoresis mass spectrometry method characterized by reducing the temporal fluctuation rate of mass spectral patterns by slowing down the movement of .