JP3187215B2 - Formaldehyde detection tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an environmental protection system for a room existing in the environment.
The present invention relates to a detection tape for detecting aldehyde by a color reaction.

[0002]

2. Description of the Related Art Formal disinfection of large environments such as hospital rooms
When using dehydrogenase is ho, also remaining after disinfecting
Confirm that the concentration of formaldehyde is below the environmental standard, and use the formaldehyde used for such disinfection.
A semiconductor gas sensor or the like is used for monitoring the generated concentration in a formaldehyde sterilizing apparatus for supplying a hide . However, semiconductor gas sensors do not have sufficient sensitivity to the concentration of environmental standards (TLV 1 ppm), and also other gases, especially formaldehyde.
It has high sensitivity to methanol used as a polymerization inhibitor for aldehyde and ammonia gas as a neutralizing agent for residual formaldehyde gas after disinfection. Is not satisfactory.

[0003] In order to solve such a problem, there have been proposed a number of detection methods by a color reaction utilizing a chemical reaction such as a silver ethylenediamine method, a potassium nickel cyanide method, a pararoseaniline hydrochloride method, an AHMT method, and an acetylacetone method. However, all of these methods require the handling of reagents because of the use of liquid reagents, which requires skill in the analysis operation, and that if automatic measurement is to be performed, the equipment becomes expensive. I have a problem. In order to solve this problem, it is conceivable to impregnate the porous carrier such as filter paper with the reagent used in each of these methods to eliminate the handling of the reagent, but the detection sensitivity is low or the background color is low. However, there are problems that the measurement range is narrow due to the large size, that it is difficult to perform automatic measurement with an optical densitometer or the like, and that the gas is easily discolored by a gas other than formaldehyde .

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to detect formaldehyde concentration with high sensitivity and reliability by using a reaction mark on a tape. Can be formal
It is to provide a dehyde detection tape.

[0005]

In order to solve such a problem, the present invention provides a method for developing an acidic salt of hydroxylamine and a hydrogen ion concentration indicator having a discoloration region in an acidic region on a porous carrier. I made it.

[0006]

The acidic salt of hydroxylamine is decomposed by formalin to generate an acid having a concentration proportional to the concentration of formaldehyde . The acid reacts with the hydrogen ion concentration indicator to form a reaction mark on the porous carrier.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on embodiments. Example 1 1.0 gram of hydroxylamine sulfate was added to 1
Dissolve in 00 ml of purified water to prepare a first liquid. A second liquid is prepared by dissolving 0.02 g of a hydrogen ion concentration indicator, metanyl yellow, which shows a color reaction with sulfuric acid, and 15 ml of glycerin in methanol to make a total volume of 100 ml. First and second
To prepare a coloring solution. After impregnating a porous carrier such as a filter paper made of cellulose or the like with the coloring solution and removing an excess coloring solution with a rubber roller or the like,
The organic solvent is dried naturally at about 40 ° C. Thus, per square meter of the porous carrier, 0.35 g of hydroxylamine sulfate and 0.15 methane yellow were added.
Gram and 21 grams of glycerin are developed.

FIG. 1 shows an example of an apparatus for measuring a gas concentration using a gas detecting tape. In FIG. 1, reference numeral 1 denotes a device arranged to face a tape 2 transport path. A through hole 3 having a diameter of about 1 cm is formed in a surface of the gas suction portion facing the tape 2 so that a negative pressure from a suction pump (not shown) acts through a pipe 4. ing.
Reference numeral 5 denotes a measuring head unit 5 arranged on the other surface of the tape 2 facing the through hole 3 of the gas suction unit 1, and a detected gas introduction port 9 is provided at a position facing the through hole 3 of the suction unit 1. Is formed as a light-shielding container having a peak wavelength of 555 nm.
And a pin type photodiode 8 having a maximum sensitivity at a wavelength of 560 nm are arranged and housed in an incident / reflective relationship so that a reaction mark formed on the tape 2 can be detected.

[0009] The above-mentioned gas detecting tape is connected to a reel 10,
When the suction gas is set to 11 and a suction pressure from a pump (not shown) is applied to the suction unit 4, the test gas is sucked into the measurement head unit 5 from the inlet 9. The test gas is discharged from the through hole 6 to the outside through the through hole 3 via the detection tape 2. In the course of the passage of the test gas through the detection tape 2, the water retained by the glycerin on the tape 2 takes in the formaldehyde, and the hydroxylamine sulfate originally present becomes 2HCHO + (NH2 OH) 2 H2 SO4 → 2H2C. = NOH + H2SO4 + 2H2O to produce sulfuric acid. The sulfuric acid reacts with the metanyl yellow present in the porous carrier to cause a color reaction of the metanil yellow in proportion to its concentration, that is, the concentration of formaldehyde, to form a reaction mark on the tape.

Thus, a predetermined sampling time,
For example, when about 40 seconds have elapsed, the suction is stopped and the process proceeds to the step of measuring the optical density of the reaction mark. Light emitting diode 7
Is absorbed according to the optical density of the reaction traces formed on the tape surface, so that the optical density before the start of the measurement, that is, the optical density difference from the background density of the tape is determined. Holmardich who passed the tape by asking
It is possible to know the concentration of de. When the measurement for one sampling is completed, the take-up reel 10 is driven to move the unused portion of the tape accommodated in the reel 11 to the measurement area.

The detection tape was set in the above measuring apparatus, and the concentration of formaldehyde was adjusted to 1000 ppm, 200 ppm.
When the optical density of the reaction trace was measured while changing the concentration to 0 ppm and Δ, the concentration was 30% as shown by the mark ● in FIG.
Detection was possible with high linearity up to about 00 ppm. Further when extending the sampling time to 60 seconds 40 seconds, the same as indicated by Dozushirushi ○ Horumua
The optical density relative to the aldehyde concentration was increased.

By the way, although in the above embodiment is made to contain glycerin carrier concentration 1000ppm over ho
When the detection target was lumaldehyde, the same sensitivity was obtained regardless of the presence or absence of glycerin. From this, it was confirmed that glycerin was an effective additive particularly when detecting low concentrations of formaldehyde .

In this embodiment, the formaldehyde
Was used hydroxylamine sulfate as a substance resulting acid reacts with de, as resolved by strong acid salts of other hydroxylamine resulting acid to cause reaction marks the meta Neil yellow hydrogen ion concentration indicator by formaldehyde, Hydroxylamine hydrochloride was used, and it was confirmed that a similar effect was exhibited even when using hydroxylamine hydrochloride. In addition to metanyl yellow, alizarin yellow, benzyl yellow, methyl yellow, and the like exist as a hydrogen ion concentration indicator that shows a color reaction to an acid generated by a reaction between a strong acid salt of hydroxylamine and formaldehyde. However, it was confirmed that the same action and effect were exhibited even when these were used.

[0014] By the way, since metaneiliroel is a hydrogen ion concentration indicator having a color change range at a hydrogen ion concentration of pH 1.2 to pH 2.3, a weakly acidic gas such as carbon dioxide gas or hydrogen fluoride existing in the air. Also, since it does not react at all with organic solvents such as alkaline gas such as ammonia and alcohol, not only can formaldehyde be detected with high selectivity, but also it can be used to detect weak acidic gas such as carbon dioxide in air. Does not react, so that it has a long-term storage property.

In the above-described embodiment, a very high concentration of formaldehyde of the order of several thousand ppm is discharged from a sterilizer or the like.
Although an example has been described in the case of detecting aldehyde , if the sampling time is extended to about 3 minutes, formaldehyde having a low concentration of about several ppm can be detected.

Example 2 A first solution is prepared by dissolving 1.0 g of hydroxylamine phosphate, which is an acid weaker than sulfuric acid and hydrochloric acid, in 100 ml of purified water. 0.04 g of a hydrogen ion concentration indicator methyl red having a discoloration region in a weak acid region and 15 ml of glycerin in methanol with a total amount of 1
Dissolve in 00 ml to prepare a second second liquid. A color developing solution is prepared by mixing the first and second liquids, and Na is added thereto to prevent discoloration due to atmospheric carbon dioxide.
CO ₃ and NaHCO ₃ , Na ₂ CO ₃ and NaOH, and Na
One kind of a buffer solution composed of a combination of HCO ₃ and NaOH is added in a predetermined amount, for example, about 30 V / V%. This preparation is impregnated into a porous carrier such as cellulose, and the excess is removed with a rubber roller or the like, and then naturally dried at about 40 ° C. The buffer solution only needs to be contained in an amount sufficient to function as a buffer with respect to the carbon dioxide gas in the atmosphere. The gas causes a color reaction of the hydrogen ion concentration indicator depending on the gas, and when the amount is more than necessary, it takes time to dry the water constituting the preparation liquid, and the working efficiency in the manufacturing process is reduced.

In the detection tape thus manufactured, 0.03 g of hydroxylamine phosphate, 0.05 g of methyl red, 21.5 g of glycerin, and an appropriate amount of a buffer solution are spread per square meter of the porous carrier. Will be done .

The detection tape is set in the above-described measuring device, and the suction time is set to 3 minutes, and the density is set to 0.
2ppm, 1.0ppm, 2.5ppm, ho of 4ppm
When a sample gas containing luumaldehyde was measured, a calibration curve as shown in FIG. 3 could be obtained. From this fact, when a weak acid salt of hydroxylamine and a hydrogen ion concentration indicator having a discoloration region of phosphoric acid generated by the decomposition thereof are used, one-third of the environmental value (TLV) of 1 ppm is used.
The following concentrations of formaldehyde, with a sensitivity to the extent that can be measured with high reliability, which can be used to adequately monitor the concentration of formaldehyde in the environment Horumuaru
Dehydrogenase detection tape can be realized, but it was found.

In this example, hydroxylamine phosphate was used as a weak acid salt of hydroxylamine. However, the same action can be obtained even if a tape is prepared using hydroxylamine oxalate in the same amount as described above. I confirmed that it would play.

In addition to methyl red, a hydrogen ion concentration indicator that shows a color reaction to phosphoric acid or oxalic acid is
Lacomoid, neutral red, etc. are known,
It was confirmed that the same effect was exhibited even when these were used.

Needless to say, the concentrations and amounts of the reagents and the like shown in the above-mentioned embodiments are both high in stability and sensitivity, and the background color of the tape by the hydrogen ion concentration indicator is as low as possible. Although the data can be suppressed to the density, it is clear that the same action can be obtained even if the above-described density and amount are changed in an appropriate range centering on the value.

[0022]

As described above, in the present invention,
Hydroxylamine acid salt and discoloration area in acidic area
And developing hydrogen ion concentration indicator on porous carrier
So it exists in the environmentFormaldehyde
Interference with a neutralizing agent or organic solvent, or even empty
Porous carrier without discoloration due to carbon dioxide in the air
It can be detected as an upper reaction mark.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a measuring device used for a detection tape of the present invention.

FIG. 2 shows the first formaldehyde detection tape of the present invention.
It is a diagram which shows the calibration characteristic with respect to formaldehyde .

FIG. 3 is a diagram showing a calibration characteristic for formaldehyde of a formaldehyde detecting tape according to a second embodiment of the present invention.

Claims (5)

(57) [Claims] 1. A formaldehyde detecting tape obtained by developing an acidic salt of hydroxylamine and a hydrogen ion concentration indicator having a discoloration region in an acidic region on a porous carrier. 2. The method according to claim 1, wherein the acidic salt of hydroxylamine is hydroxylamine sulfate, and the hydrogen ion concentration indicator is selected from methenyl yellow, alizarin yellow, benzyl yellow, and methyl yellow . Formaldehyde detection tape. 3. The hydroxylamine acid salt is at least one selected from hydroxylamine phosphate and hydroxylamine oxalate, and the hydrogen ion concentration indicator is one selected from methyl red, lacomoid, and neutral red. The formaldehyde detection tape according to claim 1, further comprising a buffer. 4. The method according to claim 1, wherein the buffer is NaCO3 and NaHCO3.
4. The method according to claim 3 , wherein at least one selected from the group consisting of Na2CO3 and NaOH, and NaHCO3 and NaOH.
Formaldehyde detection tape. 5. The formaldehyde according to claim 1, wherein the porous carrier contains a polyhydric alcohol.
Hydration detection tape.