JPH0247547A - Detecting apparatus of ionization of hydrogen flame - Google Patents

Abstract

PURPOSE:To execute a quantitative analysis of various hydrocarbons in a sample as well as all the hydrocarbons by one detecting apparatus, by providing a plurality of detection electrodes. CONSTITUTION:A component to be measured in a sample charged in a hydrogen flame 6 is burnt and ionized and a minute current being proportional to concentration is made to flow by electric fields between the opposite electrodes 11 and 12, and 11 and 28. This minute current is detected as a voltage value through amplifying elements 13 and 29 and outputted to a differential amplifier 31 directly and through a photocoder 14 respectively. An ionization energy of hydrocarbon is lower as a molecule thereof turns higher, in general, and the ionization of methane, for instance, proceeds in a high-temperature part of the hydrogen flame. Therefore, hydrocarbons other than the methane are detected by the detecting electrode 28 being smaller in length than the detecting electrode 12. Accordingly, all the hydrocarbons are detected from the amplifying element 13, while the hydrocarbons other than the methane are detected from the amplifying element 29.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a hydrogen flame ionization detection device.

<Prior art> Generally, gases do not have electrical conductivity at room temperature and pressure, but when a sufficient energy source exists to promote ionization of gas molecules, charged atoms or molecules and free electrons When a suitable electric field is applied from the outside, the gas becomes electrically conductive. A flame ionization detection device is an application of such a phenomenon, and is capable of quantitatively analyzing the component to be measured.

As such a hydrogen flame ionization detection device, for example, the one shown in FIG.
(Refer to ``MEXA-8X20 Series Service Manual'' published by Horiba, Ltd.).

That is, hydrogen supplied from the hydrogen supply source 2 to the depressurized interior space of the detector 1 through the hydrogen nozzle 3 mixes with air supplied from the auxiliary combustion air supply source 4 to the interior space of the detector 1. This air-fuel mixture is ignited by a spark plug 5 and combusted, forming a hydrogen flame 6 as an energy source necessary to promote ionization of gas molecules.

On the other hand, the collected sample containing the components to be quantitatively analyzed flows through a capillary 7 branched from a sample line 15 serving as a sample supply system, merges at a confluence point 3a formed in the hydrogen nozzle 3, and mixes with hydrogen. It is thrown into the hydrogen flame 6 from the nozzle 3. The input amount is adjusted and quantified by the adjustment action of a constant pressure adjustment device 10 disposed between the detector 1, the outlet 8 at the top of the detector 1, and the vacuum pump 9 for sucking the sample.

The component to be measured in the sample put into the hydrogen flame 6 burns in the hydrogen flame 6 and causes ionization, and when the flame 6 becomes electrically conductive, a pair of electrodes 11 and 12 facing each other with the flame 6 in between
A minute current proportional to the concentration of the ionized component to be measured flows due to the electric field between the two. This minute current is detected as a voltage value via an amplifying section 13 equipped with a high resistance, and is recorded on a photocoder 14. Since the amount of ionization captured by the electrode has a certain correlation with the concentration of the component to be measured, by knowing the voltage value mentioned above, it is possible to quantitatively analyze the unknown concentration of the component to be measured.

Note that the components to be measured that can be measured by such a hydrogen flame ionization detection device are limited to hydrocarbon compounds.

The above-mentioned hydrogen flame ionization detection device quantitatively analyzes the concentration of a component to be measured, that is, a hydrocarbon compound, in an engine cylinder during each stroke of an automobile engine that cycles through intake, compression, expansion, and exhaust in a short period of time, for example. It is effective for

<Problem to be Solved by the Invention> However, such a conventional hydrogen flame ionization detection device has a configuration in which a pair of electrodes 11 and 12 are provided, and there is only one detection electrode 12. , it is possible to obtain an output proportional to the total hydrocarbon concentration in the sample, and quantitative analysis of all hydrocarbons is possible, but it is not possible to quantitatively analyze various hydrocarbons in the sample, and it is difficult to identify the sample. Analysis was not possible.

In view of these conventional problems, the present invention aims to provide a hydrogen flame ionization detection device that can not only quantitatively analyze all hydrocarbons in a sample, but also quantitatively analyze various hydrocarbons in a sample. purpose.

Means for Solving the Problems> For this reason, the present invention ionizes a component to be measured in a sample into a hydrogen flame, and ionizes the ionized component by an electric field between electrodes facing each other with the hydrogen flame in between. A hydrogen flame ionization detection device configured to obtain a minute current proportional to the concentration of a target component and quantitatively analyze the target component based on the current, wherein a plurality of detection electrodes are provided among the electrodes. shall be.

<Operation> In this configuration, since a plurality of detection electrodes are provided,
For example, it is possible to quantitatively analyze not only all the hydrocarbons in a sample, but also various types of hydrocarbons in the sample, using the same detection device.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 1 showing an embodiment of the present invention, the same elements as those in FIG. 2 are given the same reference numerals to simplify the explanation.

In the figure, the main body of the detector 1 is composed of a base IA and a cylindrical chamber forming member IB with an open bottom and erected on the top surface of the base IA. The hydrogen nozzle 3, which serves as a hydrogen introduction passage through which hydrogen is introduced from the hydrogen supply source 2, is inserted horizontally into the base IA from the side surface of the base IA, and then bent upward at a right angle, so that the The distal end supply port 3b is projected vertically from the distal end supply port 3b and is opened into the inner space of the chamber forming member IB. Note that the vertical part of the hydrogen nozzle 3 is extended downward, and the vertical part of the hydrogen nozzle 3 is
It is opened at the bottom of the.

The air pipe 16 through which air is guided from the auxiliary combustion air supply #4 is inserted horizontally into the base IA from the side surface of the base IA, and then vertical pipe parts extend upward from multiple positions of this horizontal pipe part. The tip supply port 16a is opened into the inner space of the chamber forming member IB from a position around the hydrogen nozzle 3 on the upper surface of the base IA. A capillary 17 serving as a sample introduction path through which a sample containing a component to be quantitatively analyzed is introduced is branched from the middle of the sample line 15 and communicated with an opening in the bottom surface of the base IA of the hydrogen nozzle 3. A spark plug 5 is installed in the upper part of the chamber forming member IB.
will be placed.

A pair of electrodes 11 and 12 facing each other with the flame 6 in between is arranged within the chamber forming member IB. This electrode 11.12
is arranged at a predetermined position on a circle. The terminal of one electrode 11 is connected to one terminal of the electrode #24, the other electrode 12 acts as a first detection electrode, and the terminal is connected to the first amplifying section 1.
It is connected to one of the human power sections of the OP amplifiers 25 of No. 3. OP
The other input of amplifier 25 is grounded. The output section of the OP amplifier 25 is connected to the photocoder 14. Electrode 1
The input line between the terminal of OP AMP 2 and the input of OP AMP 25 is connected to the output line of OP AMP 25 via a resistor 26. A child terminal of the power source 24 is connected to an output line of an OP amplifier 25 via a resistor 27.

and on the circle on which the electrodes 11.12 are located,
A second detection electrode 28 is arranged near the first detection electrode 12 . This second detection electrode 28 is similar to the first detection electrode 1.
It is formed to a length shorter than 2. A terminal of the second detection electrode 28 is connected to one input section of an OP amplifier 30 of the second amplification section 29. The other input of the OP amplifier 30 is grounded. The output section of the OP amplifier 25 is connected to one input section of a differential amplifier 31, and the output section of the differential amplifier 31 is connected to the photocoder 14.

The input line between the terminal of the electrode 28 and the input of the operational amplifier 30 is connected via a resistor 32 to the output line of the operational amplifier 32. A child terminal of the power source 24 is connected to an output line of an OP amplifier 30 via a resistor 33.

Further, the output line of the OP amplifier 25 in the first amplification section 13 is connected to the other input section of the differential amplifier 31.

Next, the operation of this configuration will be explained.

The component to be measured in the sample put into the hydrogen flame 6 burns in the hydrogen flame 6 and causes ionization, and when the flame 6 becomes electrically conductive, the components that are to be measured in the sample placed in the hydrogen flame 6 burn and become ionized. A minute current proportional to the concentration of the ionized component to be measured flows due to the electric field between the electrodes 11 and 11.28. This minute current flows through the first amplifying section 13 and the second amplifying section 13 which are equipped with high resistance.
It is detected as a voltage value via the amplifying section 29. The voltage value from the first amplifying section 13 is output to the photocoder 14 and also to the differential amplifier 31.

On the other hand, the voltage value from the second amplifier section 29 is
is output to.

Generally, the ionization energy of hydrocarbons is much lower than that of polymers. For example, since methane (CH,) has a high ionization energy, ionization progresses in the high temperature part of the hydrogen flame. Hydrocarbons are detected.

Therefore, for example, all hydrocarbons are detected by the output from the first amplifying section 13, hydrocarbons other than methane are detected by the output from the second amplifying section 29, and the detected values of the hydrocarbons other than methane are Hydrocarbons other than methane can be quantified from all hydrocarbons by detecting the ratio with the detected value of hydrocarbons using the output from the differential amplifier.

In the manner described above, certain types of hydrocarbons can be quantified from among all hydrocarbons, and samples can be identified.

Note that the electrode position at which a specific hydrocarbon can be detected changes depending on the structure of the detector 1, the formation state of the hydrogen flame 6, etc. The position of the second detection electrode 28 can be moved.

In this embodiment, two detection electrodes are provided, but a plurality of detection electrodes, such as three, four, etc., may be provided so that a plurality of types of hydrocarbons can be detected simultaneously.

<Effects of the Invention> As explained above, according to the hydrogen flame ionization detection device of the present invention, a minute current proportional to the concentration of the ionized component to be measured is generated by an electric field between electrodes facing each other with a hydrogen flame in between. In a device configured to quantitatively analyze the component to be measured based on the current, it is configured with multiple detection electrodes among the electrodes, so it can only be used for quantitative analysis of all hydrocarbons in the sample. First, various hydrocarbons in a sample can be quantitatively analyzed, which improves the usability.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the hydrogen flame ionization detection device according to the present invention, in which (a) is a system diagram and (b) is an AA in (a)
A sectional view taken in the direction of arrows, and FIG. 2 is a system diagram of a conventional hydrogen flame ionization detection device. 1...Detector 3...Hydrogen nozzle 5...Ignition plug 6...Hydrogen flame 11...Electrode 12...
First detection electrode 13...first amplification section 17.
...Capillary 24...Power supply 28...Second
Detection electrode 29...second amplification section

Claims (1)

[Claims] A component to be measured in a sample is introduced into a hydrogen flame and ionized, and a minute current proportional to the concentration of the ionized component to be measured can be obtained by an electric field between electrodes facing each other across the hydrogen flame, and the current What is claimed is: 1. A flame ionization detection device configured to quantitatively analyze a component to be measured based on the hydrogen flame ionization detection device, characterized in that a plurality of detection electrodes are provided among the electrodes.