JPH02264847A - Apparatus for continuous measurement of aldehyde and formaldehyde in gas - Google Patents

Abstract

PURPOSE:To collect a very small amount of aldehyde efficiently and continuously by collecting aldehyde in a gaseous sample by the collecting solvent of a gaseous aldehyde collecting mechanism. CONSTITUTION:The gaseous sample (exhaust gas) taken out of the exhaust pipe 10 of a car is supplied to a gaseous aldehyde collecting mechanism 100 through a pump 12 and a change-over cock 14 (compensation gas introducing part). Next, aldehyde in the exhaust gas is collected by the collecting solvent such as pure water supplied from a pump 16 in the mechanism 10a and the aldehyde collecting solvent is supplied to an aldehyde measuring mechanism 200. The concn. of aldehyde in the aldehyde collecting solvent is measured in a flow state by the mechanism 200 and, from the measuring result and the collection amount of the exhaust gas by the pump 12, the concn. of aldehyde in the exhaust gas is operated. By this method, a very small amount of aldehyde can be collected efficiently, continuously and stably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a continuous airborne aldehyde measuring device and a continuous airborne formaldehyde measuring device, and particularly to improvements in the airborne aldehyde trapping mechanism and aldehyde measuring mechanism.

[Prior Art] In recent years, environmental damage caused by increased concentrations of aldehydes in the atmosphere, particularly the effects of formaldehyde, has become a problem, and the analysis of aldehydes from automobile exhaust gas and the like has become important.

Conventionally, attempts have been made to measure airborne aldehydes by connecting a gas cell to an infrared spectrometer for monitoring, or by bubbling aldehyde-containing gas, turning the airborne aldehyde into an aqueous solution, and measuring it using a colorimetric method. It was getting worse.

[Problems to be Solved by the Invention] However, the method of monitoring by connecting a gas cell to an infrared spectrometer has low sensitivity and is complicated to operate, especially for continuous monitoring of atmospheric aldehydes at low concentrations of ppb level. The problem was that

In addition, the method of trapping aldehydes in an aqueous solution by bubbling has problems with responsiveness to changes in the aldehyde concentration in the sample gas, and it is difficult to change various trapping conditions, so there are still many difficulties in continuously monitoring aldehydes in air. there were.

The present invention has been made in view of the problems of the prior art, and its purpose is to provide a continuous atmospheric aldehyde measuring device and a continuous atmospheric formaldehyde measuring device that can accurately capture even low concentrations of atmospheric aldehyde and enable continuous measurement. The purpose of this invention is to provide a measuring device.

[Means for Solving the Problems] In order to achieve the above object, a continuous atmospheric aldehyde measuring device according to the invention according to claim 1 of the present application includes an atmospheric aldehyde capturing mechanism and an aldehyde measuring mechanism. It is characterized by

The airborne aldehyde trapping mechanism then traps aldehydes in the gaseous sample in a continuously flowing trapping solvent.

The aldehyde measurement mechanism causes the aldehyde in the capture solvent to react with a reagent in a flow state, and continuously measures the amount of aldehyde.

Further, the invention according to claim 2 includes a compensation gas introduction section and a standard liquid injection section.

Then, the compensation gas introduction section replaces the gas sample with a compensation gas that does not substantially contain aldehyde, and sends the gas sample to the atmospheric aldehyde trapping mechanism.

The standard solution injector injects an aldehyde standard solution of a known concentration into the capture solvent and sends it to the aldehyde measurement mechanism.

The continuous atmospheric formaldehyde measuring device according to claim 3 is characterized in that the aldehyde measuring mechanism selectively measures formaldehyde.

[Function] The continuous airborne aldehyde measuring device according to the present invention first captures aldehyde in a gas sample into a capture solvent using an airborne aldehyde capture mechanism.

At this time, since the capture solvent is continuously flowing, changes in the aldehyde concentration in the gas sample are accurately reflected in changes in the aldehyde concentration in the capture solvent, and appropriate concentration can be achieved by changing the capture conditions if necessary. be able to.

Furthermore, in the aldehyde measurement mechanism, the aldehyde in the capture solvent is reacted with the reagent in a flow state, so changes in the aldehyde concentration in the capture solvent can be measured with good responsiveness.

As described above, according to the continuous atmospheric aldehyde measuring device according to the present invention, it is possible to measure changes in the concentration of atmospheric aldehyde with good responsiveness and accuracy.

In addition, the continuous atmospheric aldehyde measuring device is equipped with a compensation gas introduction section and a standard solution introduction section, and by introducing a compensation gas from the compensation gas introduction section instead of the gas sample, aldehyde is removed from the capture solvent. cease to exist.

By sequentially injecting aldehyde standard solutions of known concentrations from the standard solution inlet, base setting and aldehyde calibration curve creation can be performed.

In addition, by making the aldehyde measuring mechanism selectively measure formaldehyde, it becomes possible to measure the formaldehyde concentration, which is particularly a problem in terms of environmental conservation, with good responsiveness.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the continuous air aldehyde measuring device according to the present invention.

The continuous airborne aldehyde measuring device shown in the figure includes an airborne aldehyde capturing mechanism 100 and an aldehyde measuring mechanism 200.

For example, a gas sample (exhaust gas) collected from the exhaust pipe 10 of an automobile is transferred to the pump 12 and the switching cock 14 (
The gas is supplied to the atmospheric aldehyde trapping mechanism 100 via a compensation gas introduction section).

Here, in the airborne aldehyde trapping mechanism 100, the pump 1
The aldehyde in the exhaust gas is captured by a trapping solvent such as pure water supplied by 6, and the aldehyde trapping solvent is supplied to the aldehyde measuring mechanism 200.

In the aldehyde measuring mechanism 200, the aldehyde concentration in the aldehyde trapping solvent is measured in a flow state, and the aldehyde concentration in the exhaust gas is calculated from this measurement result and the amount of exhaust gas sampled by the pump 12.

Next, the aldehyde trapping mechanism 100 used in this example
The details will be explained below.

Aldehyde - FIG. 2 shows the detailed structure of the atmospheric aldehyde trapping mechanism 200 used in this example.

In the figure, an airborne aldehyde trapping mechanism 100 includes a gas sample conduction section 112, a trapping solvent conduction section 114, and an aldehyde permeable membrane section 116.

The gas sample conducting section 112 is formed into a cylindrical shape, and a gas sample inlet 118 is provided at its right end, and a gas sample outlet 120 is provided at its left end.

On the other hand, the aldehyde permeable membrane section 116 is connected to the gas sample conduction section 1
It is formed from a pipe made of a porous fluororesin membrane inserted into the interior of the trapping solvent conducting section 114 through which the trapping solvent is conducted.

The left end of the aldehyde permeable membrane section 116 is connected to the pump 16 that supplies a capture solvent (pure water in this embodiment), and the right end is connected to the aldehyde measuring mechanism 200.

Furthermore, the gas sample inlet 118 of the gas sample conduction section 112
is connected to, for example, an automobile exhaust gas pipe 10 via a switching cock 14 and a pump 12.

The switching cock 14 selectively switches between the gas sample flow path 18 and the nitrogen gas (compensation gas) flow path 20 to supply a desired gas to the gas sample introduction port 118.

Additionally, the gas sample outlet 120 is connected to a gas outlet via a pressure valve 22 .

The atmospheric aldehyde trapping mechanism according to this embodiment is constructed as described above, and its operation will be explained next.

First, the pump 16 is operated to allow pure water to flow through the capture solvent conducting section 114 at a constant flow rate.

Then, the switching cock 14 is operated to connect the gas sample flow path 18 and the gas sample inlet 118, and the pump 12 is operated.

Then, a gas sample (exhaust gas) is collected from the exhaust gas pipe 10 at a predetermined flow rate and introduced into the gas sample conducting section 112 via the switching cock 14.

The gaseous aldehyde in the gas sample passes through the aldehyde permeable membrane section 116 made of a porous fluororesin membrane, is captured by the capture solvent (pure water) flowing in the capture solvent passage section 114, and is sequentially sent to the aldehyde measurement section 200. be done.

At this point, the pressure valve 22 is operated to open the gas sample conduction section 11.
By controlling the pressure inside 2, the pressure at which the aldehyde in the gas sample permeates through the membrane portion 116 can be changed, and the aldehyde capture rate can be controlled.

Furthermore, it is also preferable to install the atmospheric aldehyde trapping mechanism 100 in a constant temperature module and heat it to a constant temperature, if necessary.

That is, by heating the trapping mechanism 100, it is possible to increase the molecular movement of the sample components in the gas sample conduction section 112, improve the permeability of aldehyde to the membrane section 116, and also increase the permeability to the aldehyde permeable membrane section 116. It is also possible to reduce adsorption of foreign components that are not permeated to the membrane or the like.

After completing the aldehyde capture in the exhaust gas as described above, next operate the switching cock 14 to
8 is connected to a gas sample introduction port 118, and nitrogen gas as a compensation gas is introduced into the gas sample conduction section 112.

As a result, the exhaust gas in the gas sample conduction section 112 is sequentially discharged from the gas sample outlet 120, and the captured solvent in the base state where no aldehyde is present is transferred to the aldehyde measuring mechanism 20.
Send to 0.

Then, each part of the capture mechanism 100 can be cleaned, and a base setting and a calibration curve can be created in the aldehyde measuring mechanism 200.

As described above, the atmospheric aldehyde trapping mechanism 1 according to this embodiment
According to No. 00, it becomes possible to efficiently trap aldehydes in exhaust gas in a trapping solvent.

Furthermore, since the flow rate of the trapping solvent in the trapping solvent conducting section 114 can be adjusted to be constant at all times, the responsiveness to changes in the aldehyde concentration in the gas sample is also extremely good.

Furthermore, it is possible to adjust the temperature of the capture mechanism 100, capture solvent flow rate, sample gas flow rate, and sample gas pressure with easy operations, and to set optimal conditions according to the type of gas sample or measurement environment.

In this embodiment, an example in which the pipe-shaped trapping solvent conducting section 114 is installed inside the cylindrical gas sample conducting section 112 has been described. It is also possible to install 112.

In addition, in this embodiment, in order to increase the area of the aldehyde permeable membrane part 116 as much as possible and improve the aldehyde trapping efficiency, the aldehyde permeable membrane part 116 formed in a spiral or bellows shape is provided in the gas sample conduction part 112. It is also suitable to install.

In addition, in this embodiment, connectors 116a and 116b are connected to the connections between the aldehyde permeable membrane section 116, pump 16, and aldehyde measuring mechanism 200, and connectors 116a and 116b are connected to the connections between the gas sample inlet 118 and the switching cock 14.
By removably providing connectors 120a at the connection portions between the 8a% gas sample outlet 120 and the pressure valve 22, the aldehyde trapping mechanism 100 itself is made replaceable.

Therefore, if the aldehyde permeable membrane section 116 becomes clogged or other parts become dirty, the trapping mechanism 100
Can be replaced completely.

Aldehyde Measurement Next, the aldehyde measuring mechanism 200 used in the airborne aldehyde continuous measuring device according to this embodiment will be explained based on FIG.

The aldehyde measuring mechanism 200 according to this embodiment has NAD
It includes an H generation section 210, a luminescence reaction section 212, and a chemiluminescence detector 214 constituting a luminescence amount measurement section.

The NADH generation unit 210 is composed of a pump 216 that supplies an NAD solution and an immobilized enzyme reactor 218, and a sample liquid supply pipe 222 is connected between the two via a solution injection injector (standard solution injection unit) 220. It is connected.

Note that aldehyde dehydrogenase is immobilized in the immobilized enzyme reactor 218.

In the luminescent reaction section 212, phenazine meso sulfate, isoluminol, and microperoxidase are used as luminescent reagents that react with N A D H.

The aldehyde measuring mechanism according to this embodiment is roughly constructed as described above, and its operation will be explained next.

First, the NAD solution fed by the pump 216 and the sample solution fed via the sample liquid feed tube 222 reach the immobilized enzyme reactor 218 in a mixed state.

Then, in the immobilized enzyme reactor 218, various aldehydes in the sample solution are oxidized to corresponding acids, and N
AD is reduced to NADH.

RCHO+NAD+H20 and phenazine meso sulfate solution pump 22
4, mixes and reacts with the NADH-containing solution sent from the NADH generation section 210, and generates hydrogen peroxide (
H20□) occurs.

Further, the isoluminol-microperoxidase mixed solution is fed by a pump 226 and mixed with the reaction solution containing hydrogen peroxide.

As a result, a luminol reaction occurs, and the amount of chemiluminescence is detected by the chemiluminescence detector 214.

In this way, the amount of luminescence detected by the chemiluminescence detector 214 corresponds to the amount of NADH produced, that is, the mole of aldehyde in the sample solution, and by comparing it with the amount of gas sample fed by the pump 12, it is possible to determine the amount of luminescence detected by the chemiluminescence detector 214. The aldehyde concentration in a gas sample can be measured.

As described above, according to the continuous atmospheric aldehyde measuring device according to the present example, since the luminol reaction is used, it is possible to perform aldehyde measurement with extremely high sensitivity.

Note that an aldehyde calibration curve can be created by injecting an aldehyde standard solution of a known concentration from the solution injector 220 and comparing the aldehyde concentration with the amount of light emitted by the chemiluminescence detector 214.

Here, when creating a calibration curve for aldehyde, the switching cock 14 is switched to the nitrogen gas flow path 20 side, and the flow path 2
It is necessary to ensure that the capture solution flowing through 22 is free of aldehydes.

Furthermore, instead of connecting the nitrogen gas flow path 32 to the switching cock 24, it is also preferable to introduce an aldehyde standard gas with a known concentration and to create a calibration curve that also takes into account the trapping efficiency of the aldehyde trapping mechanism 10.

As a result, it becomes possible to more accurately grasp the aldehyde concentration in exhaust gas.

Furthermore, in this example, the immobilized enzyme reactor 218 has been described in which aldehyde dehydrogenase is immobilized, but if, for example, one in which formaldehyde dehydrogenase is immobilized is used, only formaldehyde among the various aldehydes in the sample solution can be oxidized. And NAD
Since H is produced, it becomes possible to measure the formaldehyde concentration in the sample solution.

FIG. 3 shows the configuration of another aldehyde measuring mechanism, and parts corresponding to those in FIG.

The aldehyde measuring mechanism 200 shown in the figure includes an NADH generating section 210 and a fluorescence measuring device 214.

Then, similar to the measurement mechanism shown in FIG. 1, the NAD
The H generation unit 210 generates NADH corresponding to the amount of aldehyde present in the gas sample.

This NADH is directly measured with a fluorescence measuring device 214.

Therefore, according to the measurement mechanism according to this embodiment, it is possible to measure and understand aldehydes in a gas sample with simpler reactions and operations.

Note that, similar to the device shown in FIG. 1, the switching cock 1
4 to the nitrogen gas channel 20, a standard solution of aldehyde is injected from the solution injection injector 220, and compared with the measurement results of the fluorescence measuring device 214, thereby making it possible to set a zero base and create a calibration curve.

Furthermore, in this example, a case in which aldehyde dehydrogenase is immobilized was explained as the immobilized enzyme reactor 218, but if, for example, one in which formaldehyde dehydrogenase is immobilized is used, only formaldehyde among the various aldehydes in the sample solution is oxidized. And NAD
Since H is produced, it becomes possible to measure the formaldehyde concentration in the sample solution.

Further, as shown in FIG. 4, cyclohexane-1°3-dione is supplied by a pump 230, mixed with an aldehyde trapping solvent, and then passed through a heated reaction coil 232 to separate the aldehyde and cyclohexane-1°3-dione. It is also possible to use a mechanism in which the reaction product of 1 is measured by the fluorescence detector 214.

As described above, by using the atmospheric aldehyde capturing mechanism 100 according to the present embodiment, aldehydes in a sample gas such as automobile exhaust gas can be efficiently and continuously captured.

Furthermore, when used together with the aldehyde measuring mechanism 200 according to this embodiment, the aldehyde in the liquid flowing through the flow path 222 and the N
Since AD is reacted with a predetermined immobilized enzyme and the generated NADH is measured by a chemiluminescence method or a fluorescence method, extremely small amounts of aldehyde can be measured accurately, and the immobilized enzyme reactor 218 is configured. By changing the type of immobilized enzyme to be used, a desired measurement target such as formaldehyde or total aldehyde can be selected.

[Effects of the Invention] As explained above, according to the continuous airborne aldehyde measuring device according to the present invention, aldehyde in a gas sample is captured in the capture solvent by the airborne aldehyde capture mechanism, so that trace amounts of aldehyde can be captured in the capture solvent. It becomes possible to efficiently and continuously capture aldehydes stably.

Furthermore, since the aldehyde concentration in the trapping solvent is measured in a flow state, it is possible to measure the aldehyde concentration in the sample gas with good responsiveness and high accuracy.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of a continuous atmospheric aldehyde measuring device according to an embodiment of the present invention, and FIG. 2 is an illustration of the atmospheric aldehyde trapping mechanism used in the continuous atmospheric aldehyde measuring device shown in FIG. 3 and 4 are explanatory diagrams of other aldehyde measuring mechanisms. 14...Switching cock (compensation gas introduction part) 100...
・Airborne aldehyde capture mechanism 200...Aldehyde measurement section 220...Solution injection injector (standard solution injection section)

Claims (3)

[Claims] (1) An airborne aldehyde capture mechanism that captures aldehyde in a gas sample in a continuously flowing capture solvent, and an aldehyde measurement mechanism that continuously measures the amount of aldehyde by reacting the aldehyde in the capture solvent with a reagent in a flow state. A continuous atmospheric aldehyde measuring device comprising: (2) The measuring device according to claim 1, further comprising: a compensation gas inlet for replacing the gas sample with a compensation gas substantially free of aldehyde and sending the gas to the atmospheric aldehyde trapping mechanism; and an aldehyde standard having a known concentration in the trapping solvent. Inject the liquid,
A continuous air aldehyde measuring device characterized by comprising: a standard solution injection part for sending to an aldehyde measuring mechanism; (3) The continuous atmospheric formaldehyde measuring device according to claim 1 or 2, wherein the aldehyde measuring mechanism selectively measures formaldehyde.