JP2694667B2 - Continuous air aldehyde measuring device and continuous air formaldehyde measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a continuous air aldehyde measuring device and a continuous air formaldehyde measuring device, and more particularly to improvements in an air aldehyde trapping mechanism and an aldehyde measuring mechanism.

[Prior art] In recent years, environmental destruction due to an increase in the concentration of aldehydes in the atmosphere,
In particular, the influence of formaldehyde is becoming a problem, and analysis of aldehydes in automobile exhaust gas is regarded as important.

Conventionally, with regard to measurement of aerial aldehyde, a method of monitoring by connecting a gas cell to an infrared spectrometer or a method of bubbling an aldehyde-containing gas, converting the aerial aldehyde into an aqueous solution, and measuring by a colorimetric method, etc. have been attempted. Had been.

[Problems to be Solved by the Invention] However, in the method of monitoring by connecting a gas cell to an infrared spectrometer, the sensitivity is low especially for continuous monitoring of a low concentration ppb level airborne aldehyde, and the operation is complicated. Had the problem of being

In the method of capturing in an aqueous solution by bubbling,
There is a problem in responsiveness to changes in the aldehyde concentration in the sample gas, and it is difficult to change various trapping conditions, so that continuous monitoring of air aldehyde has many problems.

The present invention has been made in view of the above-mentioned problems of the prior art, and the object thereof is to accurately capture even low-concentration aerial aldehydes, and to continuously measure airborne aldehydes and continuous airborne formaldehyde. It is to provide a measuring device.

[Means for Solving the Problem] In order to achieve the above object, a continuous air aldehyde measuring device according to the invention of claim 1 of the present application includes an air aldehyde trapping mechanism and an aldehyde measuring mechanism, A gas sample flow path for introducing a gas sample into the air aldehyde trapping mechanism, a compensating gas flow path for introducing a compensation gas substantially free of aldehyde into the air aldehyde trapping mechanism, the gas sample flow path and the compensating gas A switching cock that selectively switches the flow path to connect to the air aldehyde trapping mechanism,
It is characterized by having.

Then, the aldehyde trapping mechanism in the air, the gas sample introduction port for introducing a desired gas from the gas sample flow path or the compensation gas flow path by operating the switching cock, and the gas sample introduced from the gas sample introduction part. A gas sample conducting section that conducts, a trapping solvent that conducts a trapping solvent, and a trapping solvent conducting section in which the trapping solvent continuously flows, and the trapping solvent are arranged between the both conducting sections and do not permeate the solvent. An aldehyde permeable membrane part that is permeable to aldehyde, and captures the aldehyde in the gas sample in a continuously flowing capture solvent.

The aldehyde measuring mechanism causes the aldehyde in the capture solvent to react with the reagent in a flow state and continuously measures the amount of aldehyde. The continuous air aldehyde measuring device according to claim 2 includes a pressure valve. The pressure valve is characterized by controlling the aldehyde capture rate by controlling the pressure in the gas sample conducting portion.

A continuous air aldehyde measuring device according to a third aspect of the invention is characterized by comprising a constant temperature means for heating the capturing mechanism to a constant temperature.

Further, the continuous airborne aldehyde measuring device according to claim 4 includes a standard solution introducing part. Then, the standard solution introducing unit injects an aldehyde standard solution having a known concentration into the capture solvent and sends it to the aldehyde measuring mechanism.

In the continuous air formaldehyde measuring apparatus according to the fifth aspect, the aldehyde measuring mechanism selectively measures formaldehyde.

[Operation] In the continuous air aldehyde measuring apparatus according to the present invention, first, the switching cock is operated to connect the gas sample flow path and the gas sample introducing port to introduce the gas sample into the gas sample conducting portion. The aldehyde in the gas sample introduced into the gas sample conducting section permeates the aldehyde permeable membrane section and is captured in the trapping solvent flowing through the trapping solvent conducting section.

At this time, since the capture solvent is continuously flowing, the change in the aldehyde concentration in the gaseous sample is accurately reflected in the change in the aldehyde concentration in the capture solvent, and the capture conditions are changed as necessary to perform appropriate concentration. be able to.

Further, the switching cock is operated to connect the compensating gas flow path and the gas sample introducing port, and nitrogen gas as compensating gas is introduced into the gas sample conducting portion. By introducing the compensating gas into the aldehyde trapping mechanism in the air, each part of the trapping mechanism is cleaned and the trapping solvent in the base state in which no aldehyde is present is delivered to the aldehyde measuring mechanism.

Further, in the aldehyde measuring mechanism, the aldehyde in the capturing solvent is reacted with the reagent in a flow state, so that the aldehyde concentration change in the capturing solvent is measured with good responsiveness.

As described above, according to the continuous air aldehyde measuring apparatus of the present invention, it is possible to accurately measure the change in the concentration of air aldehyde with good responsiveness.

Further, in the continuous air aldehyde measuring apparatus, a pressure valve is provided, and by operating the pressure valve to control the pressure in the gas sample conducting portion, the pressure when the aldehyde in the gas sample permeates the membrane portion is controlled. It can be varied to control the aldehyde capture rate.

Further, in the continuous air aldehyde measuring apparatus, a constant temperature means is provided, and by heating the capturing mechanism to a constant temperature by the constant temperature means, it is possible to improve the transmittance of the aldehyde to the aldehyde permeable membrane part, and It is also possible to reduce adsorption of different components that are not permeated to the permeable membrane part to the membrane or the like.

Further, the continuous air aldehyde measuring apparatus is provided with the standard solution introducing section, and by sequentially injecting the aldehyde standard solution having a known concentration from the standard solution injecting section, the base setting and the aldehyde calibration curve can be prepared.

In addition, by using the aldehyde measuring mechanism to selectively measure formaldehyde, it becomes possible to measure the formaldehyde concentration, which is particularly problematic in environmental protection, with good responsiveness.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a continuous airborne aldehyde measuring apparatus according to the present invention.

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

Then, for example, the gas sample (exhaust gas) collected from the exhaust pipe 10 of the automobile is passed through the pump 12 and the switching cock 14 (compensating gas introducing part) to the air aldehyde trapping mechanism 100.
Supplied to

Here, in the air aldehyde trapping mechanism 100, the pump 16
The trapping solvent such as pure water sent by the above traps the aldehyde in the exhaust gas, and the aldehyde trapping solvent is sent 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 collected by the pump 12.

Next, the aldehyde trapping mechanism 100 used in this example is
Will be described in detail.

Air Aldehyde Capture Mechanism FIG. 2 shows the detailed configuration of the air aldehyde capture mechanism 200 used in this embodiment.

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

The gas sample conducting portion 112 is formed in a cylindrical shape, and has a gas sample inlet 118 at the right end and a gas sample outlet 120 at the left end.

On the other hand, the aldehyde permeable membrane portion 116 is connected to the gas sample conducting portion 112.
It is formed from a pipe made of a porous fluororesin film inserted inside, and the inside thereof constitutes a trapping solvent conducting section 114 through which a trapping solvent conducts.

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

Further, the gas sample introducing port 118 of the gas sample conducting portion 112
Is connected via a switching cock 14 and a pump 12 to, for example, an exhaust gas pipe 10 of an automobile.

The switching cock 14 selectively switches 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.

The gas sample outlet 120 is connected to the gas outlet via the pressure valve 22.

The air aldehyde trapping mechanism according to the present embodiment is configured as described above, and its operation will be described next.

First, the pump 16 is operated to allow pure water to flow through the trapping solvent passage 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 introduction port 118 to operate the pump 12.

Then, the gas sample (exhaust gas) is sampled 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.

Then, the gaseous aldehyde in the gaseous sample passes through the aldehyde permeable membrane portion 116 made of a porous fluororesin membrane, is trapped by the trapping solvent (pure water) flowing in the trapping solvent conducting portion 114, and is sequentially sent to the aldehyde measuring portion 200. To be done.

Here, the pressure valve 22 is operated to operate the gas sample conducting section 112.
By controlling the internal pressure, it is possible to change the pressure of the aldehyde in the gas sample when the aldehyde permeates the membrane portion 116 and control the aldehyde capture rate.

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

That is, by heating the capture mechanism 100, it is possible to increase the molecular motion of the sample component in the gas sample conducting section 112 and improve the transmittance of the aldehyde to the membrane section 116. It is also possible to reduce the adsorption of different components that are not permeated to the membrane or the like.

After the aldehyde trapping in the exhaust gas is completed as described above, the switching cock 14 is then operated to remove the nitrogen gas passage 18
And the gas sample introducing port 118 are connected to introduce nitrogen gas as a compensating gas into the gas sample conducting section 112.

As a result, the exhaust gas in the gas sample conducting section 112 is sequentially discharged from the gas sample discharge port 120, and the trapping solvent in the base state in which aldehyde does not exist is sent to the aldehyde measuring mechanism 200.

Then, each part of the capturing mechanism 100 can be washed, and at the same time, the base setting and the calibration curve creation in the aldehyde measuring mechanism 200 can be performed.

As described above, the aerial aldehyde trapping mechanism according to the present embodiment
According to 100, it becomes possible to efficiently capture the aldehyde in the exhaust gas in the capture solvent. In addition, the trapping solvent conducting section
Since the flow rate of the trapping solvent in 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.

Further, the temperature of the trapping mechanism 100 can be adjusted by the easy operation of the trapping solvent flow rate, the sample gas flow rate, and the sample gas pressure to set the optimum conditions according to the type of gas sample or the measurement environment.

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

Further, in the present embodiment, in order to increase the area of the aldehyde permeable membrane portion 116 as much as possible and improve the aldehyde trapping efficiency, the aldehyde permeable membrane portion 116 formed in a spiral shape or a bellows shape is formed in the gas sample conducting portion 112. It is also suitable to install.

Further, in this embodiment, connectors 116a and 116b are connected to the aldehyde permeable membrane 116, the pump 16 and the aldehyde measuring mechanism 200, and a connector 118a and a gas are connected to the gas sample introduction port 118 and the switching cock 14. Sample outlet 12
The aldehyde trapping mechanism 100 itself is formed so as to be replaceable by providing detachable connectors 120a at the connecting portions between 0 and the pressure valve 22.

Therefore, when the aldehyde permeable membrane portion 116 is clogged or the other portion is contaminated, the entire trapping mechanism 100 can be replaced.

Aldehyde Measuring Mechanism Next, the aldehyde measuring mechanism 200 used in the continuous aldehyde measuring apparatus in the air according to the present embodiment will be described with reference to FIG.

The aldehyde measuring mechanism 200 according to the present example includes a NADH producing section 210, a luminescence reaction section 212, and a chemiluminescence detector 214 constituting a luminescence amount measuring section.

The NADH generating unit 210 is a pump 216 that supplies the NAD solution.
And an immobilized enzyme reactor 218, and a sample solution supply pipe 222 via a solution injection injector (standard solution injection section) 220 is connected between them.

In addition, aldehyde dehydrogenase is immobilized in the immobilized enzyme reactor 218.

In the luminescence reaction section 212, phenazine mezosulfate, isoluminol, and microperoxidase are used as luminescence reagents that react with NADH.

The aldehyde measuring mechanism according to the present embodiment is roughly configured as described above, and its operation will be described below.

First, the NAD solution fed by the pump 216 and the sample solution fed via the sample liquid feeding pipe 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 the corresponding acid and NA
D is reduced to NADH.

The phenazine mesosulfate solution is then pumped 22
NA sent from the NADH generator 210
Hydrogen peroxide (H ₂ O ₂ ) is generated by mixing and reacting with the DH-containing solution.

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

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

Thus, the amount of luminescence detected by the chemiluminescence detector 214 corresponds to the amount of NADH produced, that is, the molar amount of the aldehyde in the sample solution, and by comparing with the amount of gas sample fed by the pump 12, The aldehyde concentration in a gas sample can be measured.

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

A standard curve of aldehyde can be prepared by injecting an aldehyde standard solution having a known concentration from the solution injection injector 220 and comparing the aldehyde concentration with the amount of light emitted by the chemiluminescence detector 214.

Here, in preparing the aldehyde calibration curve, the switching cock 14 is switched to the nitrogen gas flow path 20 side, and the flow path 222
It is necessary that the capture solution flowing through is free of aldehydes.

Furthermore, instead of connecting the nitrogen gas flow path 32 to the switching cock 24, an aldehyde standard gas with a known concentration is introduced,
It is also preferable to create a calibration curve that also considers the trapping efficiency of the aldehyde trapping mechanism 10.

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

In addition, in the present example, the immobilized enzyme reactor 218 was described as immobilized aldehyde dehydrogenase.For example, when immobilized formaldehyde dehydrogenase was used, only formaldehyde was oxidized among various aldehydes in the sample solution. Since NADH is generated by this, it becomes possible to measure the formaldehyde concentration in the sample solution.

FIG. 3 shows the structure of another aldehyde measuring mechanism. The parts corresponding to those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The aldehyde measuring mechanism 200 shown in FIG.
And a fluorescence measuring instrument 214.

Then, as in the measuring mechanism shown in FIG. 1, NADH is used.
N corresponding to the amount of aldehyde present in the gas sample in the generation unit 210
Generate ADH.

This NADH is directly measured by the fluorescence measuring device 214.

Therefore, according to the measuring mechanism of the present embodiment, it is possible to measure and grasp the aldehyde in the gas sample with a simpler reaction and operation.

It should be noted that, like the device shown in FIG. 1, the switching cock
By connecting 14 to the nitrogen gas flow path 20 and injecting a standard solution of aldehyde from the solution injecting injector 220, and comparing with the measurement result of the fluorescence measuring instrument 214, zero base setting and calibration curve preparation can be performed.

In this example, the immobilized enzyme reactor 218 was described with immobilized aldehyde dehydrogenase.For example, when the immobilized formaldehyde dehydrogenase was used, only formaldehyde was oxidized among various aldehydes in the sample solution. Since NADH is generated by this, it becomes possible to measure the formaldehyde concentration in the sample solution.

Further, as shown in FIG. 4, cyclohexane-1,3-dione was supplied by a pump 230, mixed with an aldehyde-trapping solvent, and then passed through a heated reaction coil 232 so that aldehyde and cyclohexane-1,3-dione were mixed. 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, if the air aldehyde trapping mechanism 100 according to the present embodiment is used, it is possible to efficiently and continuously trap aldehyde in a sample gas such as exhaust gas of an automobile.

Further, when used with the aldehyde measuring mechanism 200 according to the present embodiment, the aldehyde in the liquid flowing through the channel 222 and NAD are reacted with a predetermined immobilized enzyme, and the produced NADH is measured by a chemiluminescence method or a fluorescence method. Therefore, it is possible to accurately measure an extremely small amount of aldehyde, and it is possible to select a desired measurement target such as formaldehyde or total aldehyde by changing the type of the immobilized enzyme that constitutes the immobilized enzyme reactor 218. .

[Effects of the Invention] As described above, according to the continuous air aldehyde measuring apparatus of the present invention, since the aldehyde in the gas sample is captured by the trapping solvent by the air aldehyde trapping mechanism, a trace amount of aldehyde is trapped. It becomes possible to capture aldehyde efficiently and continuously in a stable manner.

Moreover, since the aldehyde concentration in the capture solvent is measured in the flow state, the aldehyde concentration in the sample gas can be measured with high responsiveness and high accuracy.

Furthermore, since a switching cock is provided and the compensating gas is introduced into the trapping mechanism by operating the switching cock to connect the compensating gas flow path and the air aldehyde trapping mechanism, each part of the trapping mechanism. It becomes possible to wash and remove the amount of aldehyde in the trapping solvent and correct it, and it is possible to carry out highly accurate measurement.

[Brief description of the drawings]

FIG. 1 is a structural explanatory view of a continuous air aldehyde measuring device according to an embodiment of the present invention, and FIG. 2 is a view showing an air aldehyde trapping mechanism used in the continuous air aldehyde measuring device shown in FIG. FIG. 3 and FIG. 4 are detailed explanatory views of the configuration, and are explanatory views of another aldehyde measuring mechanism. 14 …… Switching cock (compensating gas introduction part) 100 …… Air aldehyde capture mechanism 200 …… Aldehyde measuring part 220 …… Solution injection injector (standard solution injection part)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Tanaka 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. (56) Reference JP-A-63-298158 (JP, A)

Claims (5)

(57) [Claims] 1. An air aldehyde trapping mechanism for trapping an aldehyde in a gas sample in a continuously flowing trapping solvent, and an aldehyde in the trapping solvent fed from the trapping mechanism is reacted with a reagent in a flow state. A continuous air aldehyde measuring device equipped with an aldehyde measuring mechanism for continuously measuring the amount of aldehyde, wherein a gas sample flow path for introducing the gas sample into the air aldehyde capturing mechanism is substantially free of aldehyde. Compensation gas flow path for introducing a compensation gas to the air aldehyde trapping mechanism, and a switching cock for selectively switching the gas sample flow path and the compensation gas flow path to connect to the air aldehyde trapping mechanism, The air aldehyde trapping mechanism is a gas sample for introducing a desired gas from a gas sample flow path or a compensating gas flow path by operating the switching cock. Between the inlet, the gas sample conducting section for conducting the gas sample introduced from the gas sample introducing section, the trapping solvent conducting section for conducting the trapping solvent, and the trapping solvent continuously flowing, and between the both conducting sections. And a aldehyde permeable membrane portion that is arranged so as to be impermeable to the solvent and permeable to the aldehyde in the gas sample. 2. The continuous air aldehyde measuring apparatus according to claim 1, further comprising a pressure valve for controlling the aldehyde trapping rate by controlling the pressure of the gas sample conducting portion. 3. The measuring device according to claim 1 or 2,
A continuous air aldehyde measuring device, comprising a constant temperature means for heating the air aldehyde trapping mechanism to a constant temperature. 4. The measuring device according to claim 1, wherein
Injecting an aldehyde standard solution of known concentration into the capture solvent,
A continuous airborne aldehyde measuring device, which is equipped with a standard solution injection part for sending to an aldehyde measuring mechanism. 5. The measuring device according to claim 1, wherein
The aldehyde measuring mechanism is a continuous air formaldehyde measuring device characterized by selectively measuring formaldehyde.