JPH05266859A - Ion source for mass analyzer - Google Patents

Abstract

PURPOSE:To maintain a resonance point at all times and stably atomize a sample, by controlling the amplification factor of an amplification means with the use of a functional value generated from a flow metering means, and controlling the oscillation frequency of an oscillation means with the use of a measured value of the current flowing through an ultrasonic vibration means. CONSTITUTION:The quantity of a sample from a column 1 is measured by a flow detection means 8 such as a flow sensor which serves as a flow metering means, and a control means is provided for controlling the amplification factor of an amplification means 5 with the use of a functional value generated from the means 8. Further, provided between an ultrasonic vibration means 3 and the amplification means 5 is a detection means for detecting the electric current flowing through that means 3 while means is provided for controlling the oscillation frequency of an oscillation means 6 in accordance with the measured value of the detection means. The liquid sample separated by the column is fed to a tip end of an ultrasonic vibration amplification means 4 by means of a tube 2 through the intermediary of the means 3. At this time, the amplification factor and the oscillation frequency are adjusted by an adjusting means A10 and the oscillation means 6, so as to cause the sample to be atomized from the tip end of the amplification means 4. By this, the means 3, means 4 and fastening fitting 7 act to keep the resonance point, for enabling stable atomization of the sample.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion source for a mass spectrometer. According to the present invention, a liquid sample introduced into the ion source is atomized with electric energy optimally suited to its flow rate. The present invention relates to an ultrasonic vibration ion source capable of maintaining a resonance state in any state of the ultrasonic vibration amplification means.

[0002]

2. Description of the Related Art FIG. 2 is an explanatory diagram showing a conventional technique. A conventional technique will be described with reference to FIG. In FIG. 2, 1 is a column, 2 is a tube, 3 is ultrasonic vibrating means,
Reference numeral 4 is an ultrasonic vibration amplifying means, 5 is an amplifying means, 6 is an oscillating means, and 7 is a fastening fitting.

The liquid sample separated by the column 1 is sent to the tip of the ultrasonic vibration amplification means 4 through the ultrasonic vibration means 3 by the tube 2. On the other hand, the ultrasonic vibrating means 3 is connected to the ultrasonic vibration amplifying means 4 with a certain tightening torque by a tightening metal fitting 7. On the other hand, the ultrasonic vibrating means 3 is the amplifying means 5 connected to the oscillating means 6.
The high frequency energy is supplied by. The high frequency energy amplified by the amplification means 5 is transmitted to the ultrasonic vibration means 3
Is converted into vibration energy by the ultrasonic vibration amplification means 4
The liquid sample is amplified by and is atomized. Now, in FIG. 2, when the distance from the end of the tightening metal fitting 7 to the tip of the ultrasonic vibration amplifying means 4 is X, the overall resonance frequency of the tightening metal fitting 7, the ultrasonic vibrating means 3, and the ultrasonic vibration amplifying means 4 is , Is represented by the following approximate expression.

Fo = K / X (Equation 1) Fo: Resonance frequency K: Resonance constant X: Overall length Here, the relationship between the resonance frequency of Fo and the current flowing through the ultrasonic vibration means 3 is shown in FIG. At the resonance point (Fo), the vibration energy is the frequency at which the vibration energy is transmitted to the ultrasonic vibration amplification means 4 with the maximum efficiency, and the high frequency current flowing through the ultrasonic vibration means 3 at this time becomes the maximum value (Im), Only in this case, the liquid sample is atomized from the tip of the ultrasonic vibration amplification means 4.
Further, the resonance constant K is a unique constant of the ultrasonic vibrating means 3, and in the prior art, a group of piezoelectric elements is used for the ultrasonic vibrating means 3, and a value of K = 1500 kHZ to 2000 kHZ is used. It was Here, K has a width of 500 kHz because of the temperature of the ultrasonic vibration means 3 and the ultrasonic vibration amplification means 4 connected to the ultrasonic vibration means 3.
This is because it changes depending on the mass number of.

Examples of such conventional techniques include a method of introducing a sample into an analyzer and an apparatus disclosed in Japanese Patent Laid-Open No. 56-126241.

[0006]

As is apparent from the above description of the prior art, in the prior art, the ultrasonic waves accompanying the temperature change of the ultrasonic vibrating means 3 and the increase / decrease of the liquid sample from the column 1 are used. Due to the change in the mass number of the vibration amplifying means 4, the Fo (resonance frequency) of the equation (1) changes, and it is necessary to change the frequency of the oscillating means 6 each time. Further, in the prior art, since the amplification factor of the amplification means 5 is constant regardless of the flow rate of the sample, unnecessary electric energy is continuously supplied to the ultrasonic vibrating means 3 depending on the sample amount, and the energy loss is large. It was also linked to the cause of heat generation of the ultrasonic vibration means 3.

[0007]

[Means for Solving the Problems] As means for solving the problems, in the means of claim 1, first, a flow rate measuring means such as a flow rate sensor for measuring the amount of the sample from the column 1 is provided.
Amplifying means 5 according to the function value generated by the flow rate measuring means
It is achieved by providing means for controlling the amplification factor of. Further, in the means of claim 2, since the above-mentioned resonance frequency Fo is a frequency applied to the ultrasonic vibration means 3 when the current flowing through the ultrasonic vibration means 3 becomes maximum, the ultrasonic vibration means This is achieved by providing a means for detecting the current flowing in the ultrasonic vibration means 3 between the amplifier 3 and the amplification means 5, and providing a means for controlling the oscillation frequency of the oscillation means 6 according to the measured value.

[0008]

As described in the means for solving the above problems, the sample from the column 1 is measured by the flow rate measuring means,
If the amplification factor of the amplification means 5 is controlled by the generated function value, electric energy proportional to the sample flow rate can be sent to the ultrasonic vibration means 3. Further, by controlling the oscillation frequency of the oscillating means 6 so that the current flowing into the ultrasonic oscillating means 3 is always maximized, it is possible to change the temperature of the ultrasonic oscillating means 3 and increase or decrease the mass of the ultrasonic oscillating amplifying means 4. Even if the resonance frequency changes accordingly, the oscillation means 6 always maintains the entire resonance state of the ultrasonic vibration means 3, the tightening metal 7, and the ultrasonic vibration amplification means 4.

[0009]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a column, 2 is a tube, 3 is ultrasonic vibrating means,
4 is ultrasonic vibration amplifying means, 5 is amplifying means, 6 is oscillating means, 7 is tightening fitting, 8 is flow rate detecting means, 9 is amplifying means A, 10 is adjusting means A, 11 is switching means S1, 12 is addition Means, 13 is switching means S2, 14 is voltage-frequency converting means, 15 is amplifying means B, 16 is switching means S2 ', 1
7 is switching means B, 18 is amplification means C, 19 is smoothing means,
20 is a detection means.

In FIG. 1, all of the switching means S1-11, the switching means S2-13, and the switching means S2'-16 are now on the side a. Further, the ultrasonic vibration means 3 is connected to the ultrasonic vibration amplification means 4 with a certain tightening torque by means of a tightening fitting 7. The liquid sample separated by the column 1 is supplied to the tip of the ultrasonic vibration amplifying means 4 through the ultrasonic vibration means 3 by the tube 2. At this time, the amplification unit and the oscillation frequency are adjusted by the adjusting unit A-10 and the oscillating unit 6, and the liquid sample is atomized from the tip of the ultrasonic vibration amplifying unit 4. That is,
In this state, the ultrasonic vibrating means 3, the ultrasonic vibration amplifying means 4, and the tightening fitting 7 are all in a resonance state. At this time, the frequency at the point a of the switching means S2-13 and the voltage at the point a of the switching means S1-11 are measured. In this example, the frequency was 28.5 kHz and the voltage was 8.0V. Next, the frequency at the point b of the switching means S2-13 is 28.5 of the measurement frequency.
The adjusting means B-17 is adjusted so that it becomes kHZ, and the voltage at the point c of the adjusting means B-17 at this time is measured. In this example, this voltage was 2.4 V. Next, the switching means S
The amplification factor of the amplifying means B-17 is adjusted so that the voltage at point b of 2'-16 becomes similar to the voltage value (2.4 V) at point c of the adjusting means B-17. This voltage value is the ultrasonic vibration means 3, the ultrasonic vibration amplification means 4, and the tightening metal fitting 7.
Is the value of the input current to the ultrasonic vibrating means 3 in the entire resonance state of, and corresponds to Im in FIG. It should be noted that this current has a value converted into a voltage by the detecting means 20. Next, the switching means S1-11 and the switching means S2'-16 are turned on to the side b, respectively. Then, the amplifying means 5 and the adding means 12 are always in the resonance state of the whole of the ultrasonic vibration means 3, the ultrasonic vibration amplification means 4, and the fastening fitting 7.
(The current flowing through the ultrasonic vibrating means 3 is controlled to be always the maximum). Even when the sample amount of the liquid separated from the column 1 is changed, the function value generated from the flow rate detecting means 8 and the amplification factor of the amplifying means 5 by the amplifying means A-9 are such that the liquid sample has a resonance action. By this, the value is controlled to the most suitable value for atomization. According to this example, when the liquid sample amount was changed to 1 to 10 μl / min, the voltage applied to the ultrasonic vibrating means 3 was automatically changed to 6.2V to 12.3V.

[0011]

As described in the above embodiment, according to the present invention, the voltage applied to the ultrasonic vibrating means 3 is automatically changed in proportion to the amount of the sample flowing out from the column 1. The value was 6.2V to 12.3V for the applied voltage with respect to the sample flow rate of 1 to 10 μl / min. The initial value of the current flowing into the ultrasonic vibrating means 3 has a frequency of 28.5 kHz.
It was 2.8A, but after 30 minutes, the frequency was 29.
At 5 kHz, the current value was 2.8 A, and the resonance state was always maintained. As described above, according to the present invention, there is an effect that the resonance point is always maintained and the sample can be stably atomized without being affected by the change of the liquid sample flow rate and the temperature change of the ultrasonic vibrating means 3.

[Brief description of drawings]

FIG. 1 is a simplified circuit diagram showing an embodiment of the present invention.

FIG. 2 is a simplified circuit diagram showing a conventional technique.

FIG. 3 is a relationship diagram between a resonance frequency and a current flowing through the ultrasonic vibration means 3.

[Explanation of symbols]

1 ... Column, 2 ... Tube, 3 ... Ultrasonic vibrating means, 4 ...
Ultrasonic vibration amplification means, 5 ... Amplification means, 6 ... Oscillation means, 7
... Tightening hardware, 8 ... Flow rate detecting means, 9 ... Amplifying means A,
10 ... Adjusting means A, 11 ... Switching means S1, 12 ... Addition means, 13 ... Switching means S2, 14 ... Voltage-frequency conversion means, 15 ... Amplification means B, 16 ... Switching means S2 ′, 17 ...
Switching means B, 18 ... Amplifying means C, 19 ... Smoothing means, 20
… Means of detection.

Claims (2)

[Claims] 1. An ion source of a mass spectrometer comprising an ultrasonic vibrating means, an oscillating means, an amplifying means, and an ultrasonic vibrating amplifying means, the flow rate of a sample supplied to the ion source is measured, and the measured value is followed. An ion source for a mass spectrometer, further comprising means for generating a certain function, and means for varying the amplification factor of the amplifying means according to the generated function. 2. The ion source according to claim 1, wherein current detecting means is provided between the ultrasonic vibrating means and the amplifying means so that the voltage detected by the current detecting means is always constant. Ion source for a mass spectrometer, characterized in that the control means is provided so that the oscillation frequency of the oscillating means always maintains the resonance frequency of the ultrasonic vibrating means.