JP2001013076A - Hydrogen cyanide detection paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the influence of atmosphere and natural light as much as possible, and to accurately measure hydrogen cyanide for a long time by developing a color developing agent whose color is changed by the oxidation force of copper acetate (II), antioxidant, humectant, and copper cyanide on carrier paper. SOLUTION: A tape 1 is accommodated into a cassette 2, and the tape can be transported at each fixed time to a sampling head 6 with a light-emitting device 4 and a photo detector 5 by a tape transport mechanism 3, and the concentration of hydrogen cyanide can be automatically measured. The sampling head 6 is connected to environment to be measured via a sampling pipe 7, and cooperates with a suction head 9 being connected to a suction pump via a pipe 8 for sealing the tape 1. As a result, when the suction pump is actuated for fixed time, a specific amount of air passes through the tape 1, copper cyanide is generated by chemical reaction, and tetramethyldiaminophenylmethan being a color developing agent is colored by the oxidation force of the copper cyanide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen cyanide detecting paper for measuring the density by causing a color reaction with hydrogen cyanide contained in an atmosphere.

[0002]

2. Description of the Related Art Hydrogen cyanide has been used widely for fumigation of foods such as cereals and vegetables because of its extremely low persistence and relatively high toxicity. Fumigation with hydrogen cyanide is performed by maintaining the concentration of hydrogen cyanide in the airtight space at a few percent and storing the article to be fumigated therein for several hours or more. After fumigation, hydrogen cyanide has an allowable concentration of 5.
After confirming that the content has decreased to ppm or less, the operation of removing the article to be fumigated is performed.

[0003]

The permissible concentration was confirmed by a hydrogen cyanide detector tube, a Berlin Blue reaction, a Rodin reaction,
Although it is performed by the pyridine pyrazolone method or the like, there is a problem that efficiency is low because of batch processing. In order to solve such a problem, it is also possible to automatically manage using a so-called detection tape in which a colorant reacts with the test gas to produce a reaction mark corresponding to the concentration of the test gas on the tape, that is, a so-called detection tape. Although it is conceivable, there is a problem that the optical density changes under the influence of atmospheric oxygen and natural light, and the measured value includes large detection. The present invention has been made in view of such circumstances, and an object thereof is to measure hydrogen cyanide with high accuracy over a long period of time by preventing the influence of the atmosphere and natural light as much as possible. The object is to provide hydrogen cyanide detection paper.

[0004]

In order to solve the above-mentioned problems, the present invention carries copper (II) acetate, an antioxidant, a humectant, and a coloring agent which changes its color due to the oxidizing power of copper cyanide. I developed it on paper.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on embodiments. Copper acetate (II) [Cu ₂ (CH ₃ COO) 4
(H ₂ O) ₂ (monohydrate)] 0.05% by weight, an antioxidant such as butyl hydroxyl toluene 0.2% by weight,
A coloring agent, for example, 0.15 wt% of tetramethyldiaminodiphenylmethane, and a humectant, for example, 15 ml of a polyhydric alcohol such as glycerin or ethylene glycol, are dissolved in an easily evaporable organic solvent such as methanol in this embodiment so that the total amount becomes 100 ml. To prepare a coloring solution.

The color developing solution is impregnated into a supporting paper, for example, a filter paper made of cellulose, and the organic solvent is volatilized while being heated if necessary. Note that, in order to promote the reaction with the test gas, a sheet material in which fine powder such as silica gel or alumina is mixed in advance is used, or fine powder such as silica gel or alumina is mixed in a coloring solution and supported on the sheet material. Is desirable.

As a result, a detection paper is obtained in which 0.046 g of copper (II) acetate, 0.14 g of tetramethyldiaminodiphenylmethane, 0.18 g of butylhydroxyl toluene and 26 g of a humectant are spread per square meter of the supporting paper. In addition, copper (II) acetate and tetramethyldiaminodiphenylmethane constituting the color-forming system are used in appropriate amounts, that is, 0.146 based on the above-mentioned values of 0.046 g of copper (II) acetate and 0.14 g of tetramethyldiaminodiphenylmethane. Double to 1
Hydrogen cyanide can be detected with a predetermined sensitivity as long as it is appropriately selected in the range of 0 times, but the above-mentioned concentration is preferable in consideration of uneven coating on the carrier and cost.

The detection paper can be cut into a tape and used as a detection tape for an automatic measuring device, or cut into paper pieces and used as a detection material for a detection badge.

In particular, when the tape 1 is processed, the tape 1 is housed in a cassette 2 as shown in FIG. It can be transported every time,
The concentration of hydrogen cyanide can be measured automatically.
The sampling head 6 is connected to the environment to be measured via a sampling pipe 7 and is configured to seal the tape 1 in cooperation with a suction head 9 connected to a suction pump via a pipe 8. I have.

By operating the suction pump for a certain period of time, a predetermined amount of air passes through the tape 1, and

Embedded image The reaction produces copper cyanide, and its oxidizing power causes the color former, tetramethyldiaminodiphenylmethane, to develop color. As a result, a blue reaction mark is formed on the tape 1 in proportion to the concentration of hydrogen cyanide, so that the concentration of hydrogen cyanide can be measured by detecting the relative optical density of the reaction mark with the light emitting element 4 and the light receiving element 5. .

In the above-described embodiment, the fluid to be measured is allowed to react by passing through the sheet material. However, as shown in FIG. 10 has an inlet 11 on one side and an outlet 1 on the other end.
2, the same measurement can be performed even when the fluid to be measured flows through one surface of the sheet material by using a sampling head constituted by providing the light emitting element and the light receiving element described above.

FIG. 2 shows that the gas flow rate to be sampled using the hydrogen cyanide detection paper is maintained at 400 ml / min, and the sampling time is 60 seconds (A in the figure, 40 seconds in B, and 20 seconds in C). The relationship between the concentration of hydrogen cyanide and the relative optical density was measured while changing.

FIG. 3 shows that the gas flow rate to be sampled using the hydrogen cyanide detection paper is maintained at 400 ml / min, and the concentration of hydrogen cyanide (symbol A in the figure is 15 ppm, symbol B is 10 ppm, and symbol C is 5 ppm) is changed. It is a result of measuring the relationship between the sampling time and the relative optical density.

FIG. 4 shows the above-mentioned coloring solution, that is, 0.05% by weight of copper (II) acetate and 0.1% of butylhydroxyl toluene.
2 wt%, tetramethyldiaminodiphenylmethane 0.
15 wt% and glycerin were dissolved in methanol so that the total amount was 100 ml. The glycerin concentration of the coloring solution was changed, and the sampling flow rate was 400 ml / min. It shows the optical density. From this, glycerin was added at a color developing solution level from 8.55 to 24.5.
1 v / v% (15 to 43 per square meter of detection paper)
It can be seen that g) is an amount suitable for improving the detection sensitivity.

On the other hand, the detection paper of the present invention, that is, the support paper 1
0.046 g of copper (II) acetate, 0.14 g of tetramethyldiaminodiphenylmethane, 0.18 g of butylhydroxyltoluene, 26 g of humectant per square meter, and a detection paper containing no butylhydroxyltoluene (hereinafter, a comparative detection paper) And measuring the specified concentration of hydrogen cyanide at the specified sampling time, the same optical density change occurred.

On the other hand, after leaving the detection paper of the present invention and the detection paper for comparison at 30 cm immediately below a 20-w fluorescent lamp for 8 hours,
When the specified concentration of hydrogen cyanide was measured at the specified sampling time, the change in the relative optical density of the detection paper of the present invention, that is, the measured value was 0.93, whereas the comparison detection paper detected 0.48. The sensitivity was reduced by almost half.
From this, it has been found that adding butylhydroxyl toluene which is an antioxidant is a very effective means for preventing a decrease in sensitivity.

A detection paper having a different butylhydroxyltoluene concentration was applied to 30 cm immediately below a 20-w fluorescent lamp.
After standing for a period of time, a change in the detection sensitivity was examined. As a result, it was found that a drop in sensitivity could be prevented if the detection paper level was 0.1 g or more per square meter. The upper limit is defined by the saturation concentration of the coloring solution and is 1.0 g per square meter.

In the above embodiment, copper cyanide produced by the reaction with hydrogen cyanide is detected by the color reaction with tetramethyldiaminodiphenylmethane. However, the color reaction is caused by the oxidizing power of the copper cyanide. A similar effect can be obtained by using a coloring system which does not cause interference with hydrogen cyanide, such as an iodine-starch reaction or N, N-diethyl-P-phenylenediamine sulfate. In addition, the color former which reacts with copper cyanide to produce a color has an appropriate concentration.

[0019]

As described above, in the present invention,
Copper (II) acetate, an antioxidant, a humectant, and a coloring agent that changes color due to the oxidizing power of copper cyanide were developed on the supporting paper.
Even if left in the air or natural light for a long time, the discoloration degree is low,
Hydrogen cyanide on the order of ppm can be detected with high sensitivity and accuracy.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are a diagram showing one embodiment of a measuring device which uses the hydrogen cyanide detection paper of the present invention by shaping it into a tape, and a diagram showing another embodiment of a sampling head, respectively. It is.

FIG. 2 is a graph showing the dependence of the relationship between the concentration of hydrogen cyanide and the relative optical density on the hydrogen cyanide detection paper of the present invention with respect to the sampling time.

FIG. 3 is a diagram showing the dependence of the relationship between the sampling time and the relative optical density of the hydrogen cyanide detection paper of the present invention on the hydrogen cyanide gas concentration.

FIG. 4 is a diagram showing a relationship between a humectant carried on the detection paper and the relative optical density.

Continued on the front page F term (reference) 2G042 AA01 BB19 CA01 CB01 DA03 DA08 FA04 FA11 FA19 FA20 FB07 FC01 GA04 2G054 AA01 CA04 CE01 CE10 EA04 EA06 EB03 FA32 FA33 GE02 GE06

Claims (4)

[Claims] 1. A hydrogen cyanide detection paper obtained by developing copper (II) acetate, an antioxidant, a humectant, and a coloring agent that changes color by the oxidizing power of copper cyanide on a supporting paper. 2. The hydrogen cyanide detection paper according to claim 1, wherein silica gel or alumina powder is mixed in the support paper. 3. The antioxidant is butylhydroxyl toluene, and 0.1 g to 1.0 g / m 2.
The hydrogen cyanide detection paper according to claim 1, which contains g. 4. The color former according to claim 1, wherein the color former is tetramethyldiaminodiphenylmethane, N, N-diethyl-P-phenylenediamine sulfate, or iodine-starch.
The hydrogen cyanide detection paper according to the above.