CA2126738C - Oxidizing gas detector paper - Google Patents
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
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Abstract
A sheet of paper is immersed in a reacting solution prepared by dissolving p-n-butoxyaniline, an ultraviolet absorber and polyalcohol in an organic solvent. Then, the organic solvent is allowed to evaporate. Thus, the p-n-butoxyaniline and ultraviolet absorber are spread over the sheet of paper by using the water absorbed in the polyalcohol that serves as a medium for reaction. When the paper is exposed to chlorine or other oxidizing gas, the p-n-butoxyaniline colors, aided by the water absorbed in the, polyalcohol, to form a trace of reaction according to the concentration of the oxidizing gas. Because the ultraviolet absorber prevents the reaction between the p-n-butoxyaniline and light, no discoloration-induced sensitivity drop occurs during storage.
Description
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_ ~~~~~~le$~
SPNCIFICATION
Title of the Invention Oxidizing Gas Detector Paper Background of the Invention Field of the Invention This invention relates to detector paper used to determine the concentration of chlorine, ozone and other oxidizing gases by utilizing the coloring reaction.
Description of the Prior Art Chlorine, ozone and other oxidizing gases (hereinafter generically referred to as oxidizing gases) are used in large quantities as materials for various industrial pro-ducts and disinfectants. Because of their high. toxicity, however, their allowable concentration in the work environ-ment is limited to as low as, for example, 0.5 ppm.
The concentration of chlorine; gas in the environment is usually monitored by a galvanic-cell 'type electrochemi-cal gas sensor to. ensure that the re:~erence concentration level is not exceeded.
However, electrochemical gas sensors of this type are sensitive to too many different kinds of gase,~, such as alcohol and,other reducing gases and many other different kinds of gases present in the enva.ronment. , Therefore, they do not have high enough selectivity ~or the object oxidiz-ing gas. .
_ ~~~~~~le$~
SPNCIFICATION
Title of the Invention Oxidizing Gas Detector Paper Background of the Invention Field of the Invention This invention relates to detector paper used to determine the concentration of chlorine, ozone and other oxidizing gases by utilizing the coloring reaction.
Description of the Prior Art Chlorine, ozone and other oxidizing gases (hereinafter generically referred to as oxidizing gases) are used in large quantities as materials for various industrial pro-ducts and disinfectants. Because of their high. toxicity, however, their allowable concentration in the work environ-ment is limited to as low as, for example, 0.5 ppm.
The concentration of chlorine; gas in the environment is usually monitored by a galvanic-cell 'type electrochemi-cal gas sensor to. ensure that the re:~erence concentration level is not exceeded.
However, electrochemical gas sensors of this type are sensitive to too many different kinds of gase,~, such as alcohol and,other reducing gases and many other different kinds of gases present in the enva.ronment. , Therefore, they do not have high enough selectivity ~or the object oxidiz-ing gas. .
2.~~~~~~~
To overcome this shortcoming, detector paper made by spreading a solution prepared by dissolving p-methoxyani-line, which colors on reaction with chlorine and other oxidizing gases, in a solvent over paper or.other carriers.
However, p-methoxyaniline tends to discolor when exposed to light. This discoloration resulting from expo- .
sure to light is difficult to distinguish from the coloring reaction with oxidizing gases that is used for the deter-urination of their concentration by optical means. This. can lead to the lowering of detection sensitivity.
Summary of the Invention To solve the problem described above, the oxidizing gas detector paper of this invention is prepared by spread-, ing p-n-butoxyaniline, an ultraviolet absorber and polyal-cohol.over a sheet of paper that serves as a carrier.
Object and Effect of the Invention The object of this invention is to provide.oxidizing gas detector paper that is immune to the interference of organic solvent, and other substances in the environment, has high resistance, to light and maintain a uniform.detec-tion sensitivity for a long period of t~.me.
Brief Description of the Drawings Fig. 1 is a cross-sectional view of an example of a measuring instrument that uses theyoxidizirig gas 'detector paper of this invention. Fig. 2 shows the measureznen'ts obtained by the oxidizing gas detector paper of this inven-tion, in which the concentration of chlorine gas is plot-ted, using the sampling time as a parameter. Fig. 3 shows the relationship between the reaction time of oxidizing gas detector. paper of this invention and changes in the concen-tration of an oxidizing gas, using the concentration of the oxidizing gas as a parameter. Fig. 4 graphically shows changes in the relative output obtained fram oxidizing gas detector paper of this invention exposed to light. Fig. 5 shows the relationship between the concentration of.a humectant and the relatiue output.
Description of the Preferred Embodiments Details of this invention' will be made.explicit in the following description of preferred, embodiments.
[example 1]
A reacting solution.of 100 milliliter was prepared by dissolving 1.0 gram of p-n-butoxyaniline, 1.7 gram of butylated liydroxyboluene as an ultraviolet absorber and 15 v/v o of polyalcohol, such as glycerin, as a humec~tant in metha~zol or other. organic' solvent.
A sheet of cellulose-based paper was immersed in the reacting solution thus prepared to allow the paper to i 'absorb the solution. The. paper lifted out of~the solution was passed through rollers of silicone rubber to squeeze out excess solution.. The squeezed paper was'allowed to stand in an environment at 40° C to allow the organic sol-vent to evaporate.
The oxidizing gas detector paper thus prepared con-tamed approximately 0.6 gram of p-n-butoxyaniline, appro-ximately 1.0 gram of butylated hydroxytoluene and 25 grams of glycerin per square meter.
Fig. 1 shows an, example of an instrument that dete-rmines the concentration of gas by using the oxidizing gas detector paper of this invention. In the drawing, refer-ence numeral 1 designates a gas suction device provided in the path of a tape of detector paper 2. The gas sucvtion device 1 has a through hole 3 having a diameter.of approxi-mately 1 cm that opens. in the surface thereof that faces the detector papex 2. A negative pressure, is supplied from a suction pump, not shown, through a pipe 4:
Reference numeral 5 denotes a measuring head disposed on the other side of the detector paper 2 opposite to the through hole 3 in the gas suction device 1. The measuring head 5 constitutes alight-shielding means having.a gas inlet 6 located in a position opposite. to the through hole 3 in the gas suction device 1. The measuring;head 5.con-tams'a light-emitting diode 7'emitting a Tight having~a peak wavelength;. of 555, nm and a pin-type photodiode 8 that exhsbits maximum sensitivity to'a light having a wavelength of 560 nm. ,The light-emitting diode 7 and,photodiode 8 are disposed in such a position that they can detect a trace of reaction formed on the detector paper 2.
After the tape of gas detector paper 2. is set over reels 10 and 1I, the suction pressure supplied from the pump not shown to the suction device 4 draws the object gas through an intake 9 to the measuring head 5. The object gas from the gas inlet 6 is discharged outside after pass-ing through the ;tape of detector paper 2 and 'the through hole 3. When the~object gas passes through the tape of detector paper 2, p-n-butoxyariiline on the tape 2 selec-tively reacts with an oXidi.zing gas to form a trace of reaction.
After sampling time.of,a given length,. such as appro-ximately 40 seconds; has passed, the suction of the object gas is stopped to determine the optical concentration of the trace of. reaction:
The light from the light-emitting diode 7 is absorbed according to the.optical concentration.of the trace of reaction formed on the surface o~ the tape. ;Therefore; the concentration or .the cumulative amount of the oxidizing gas that has passed.through the tape can.be obtained by deter-zniriing the difference between the opvtical concen~ratioi~s of the'tap~ before end after the suction of the object gas.
The optical concentration of the tape before.the .suction,i hat of the background of the tape:
When the measurement of one sampling is complete, the takeup reel 10 is turned to feed an unused portion of the tape 2 into the measuring zone.
Sample gases containing different concentrations of, chlorine gas were tested by setting the oxidizing gas detector paper of this invention on the device just de-scribed. Fig. 2 shows the obtained results.
In Fig. 2, curves L, II and III plot the measurements obtained with a sampling time of 20, 40 and 60 seconds, re-spectively. As evident from the figure, the oxidizing gas detector paper of this invention has sufficient sensitivity to oxidizing gases of as.low a concentration as approxi-matPly 0.l ppm. When the length of sampling time is in- .
creased, the amouyt of oxidizing gas working on the detec-for paper increases. This increase creates a cumulative effect to raise the optical concentration of gases of even lower concentrations, which,. in turn, permits measurement.
with high degrees of accuracy.
The optical concentrations of the traces of reaction formed by sample gases'I, II, III and III, each containing , 0.2, 0:5, 1.0 and 1.5 ppm of chlorine gas; were measured at given time intervals by varying their sampling time.. E'ig>, 3 shows the obtained results.
If a shorter sampling t~.me is set; the measurement of sample gases ITI and IV containing,higher concentrations of chlorine gas can be completed in a very short time.
With sample gases I and TI containing lower concentra-tions of chlorine gas, by comparison, the xelative output increases with an increase in the sampling t,~me.
Obviously, a wide range of concentrations of oxidizing Base can be measured by setting an appropriate sampling time suited for 'the concentration of each oxidizing gas to be detected.
The oxidizing gas detector paper described above was placed directly under and 30 cm away from a fluorescent lamp to irradiate a light of approximately 1500 lutes.
Chlorine gas of a fixed concentration was measured with the paper irradiated over different lengths of time. Then, the sensitivity of the paper irradiated for 6.hours did not drop substantially, as indicated by a curve marked with ~
in Fig. 4.
For the purpose of comparison, detector paper not containing the ultraviolet absorber was prepared to perform a similar test by using. chlorine gas of a fixed' conceritra-tion: Theri, the sensitivity of 'the. paper decreased with iricreasing,exposure time to light, as indicated by a curve .
marked with ~L1 in Fig. 4. I
As is obvious from this test, addition of the ultravi-olet absorber. increases the resistance of the detector paper to light, thereby allowing the'paper to keep its detection sensitivity intact over a long period of time.
While accelerating the reaction between the coloring reagent and oxidizing gas, the humectant has a great effect on the gas permeability of the detector paper because of its viscosity. Therefore, it can decrease the amount of the object gas passing through the paper, depending on the performance of the sampling pump of the gas detector..
Accordingly, there is a certain concentration,~that allows the paper to.exhibit the maximum sensitivity,.as,shown in Fig..5.
When the concentration of the humectant is low, there is less water that serves as.the medium for reaction. This decreases the speed of reaction between p-n-butoxyaniline and an oxidizing gas and, therefore, lowers the sensitivity of the detector paper. When the concentration. of the humectant in the prepared solution is between,2 and l5 v/v %, the sensitivity of the detector paper increases unvary-ingly with increasing concentration: When the concentra-tion ~~ceeds 15 v/v ~, the'detector paper allows an iri-creasingly sniall'quantity.of the object gas to pass through, thereby lowering the apparent sensitivity thereof.
Therefore; the quantity of the humectant carried,iby the detvector paper should preferably be limited between approximately 3 to 35 grams per square meter.y instead of glycerin used in this: embodiment; other po~.yalcohoi, such T
as ethylene glycol, may be used as the humectant to obtain a similar effect.
[Example 2]
A reacting solution of 100 milliliter was -prepared by dissolving 1,0 gram of p-methoxyaniline, 1.7 gram of butyl-ated hydroxytoluene as an ultraviolet absorber and 15 v/v o of polyalcohol, such as glycerin, as a humectant in metha-nol or other organic solvent.
A sheet of cellulose-based paper was immersed in the reacting solution thus prepared to allow the paper to absorb the solution: The paper lifted out of the solution was; passed through rollers of silicone rubber to squeeze out excess solution. The squeezed paper was allowed to stand in an 2nVironment at 40° C to allow the organic sol-vent.to evaporate.
The oxidizing gas detector paper thus prepared con-tained approximately 0.6 gram of p-m.ethoxyaniline, appro-ximately 1.O gram of butylated hydroxytoluene and 25 grams of glycerin per square meter:
By using the gasdetector paper thus obtained, and the samp,li.ng'time and the concentration of oxidizing gas, respectively, as a parameter,v the obtained measurement's and relationship between sampling 'time and the concentration of the'trace of reaction were investigated, as in the case of the:first example described before. 'The results were substantially similar to those obtained in the first exam-ple.
The oxidizing gas detector paper described above was.
placed directly under and 30 cm away from a fluorescent lamp to irradiate a light of approximately 1500 luces.
Chlorine gas of a fixed concentration was measured,with the paper irradiated over different lengths of time. A curve marked with in Fig. 4 plots the results obtained.
For the purpose of comparison, detector paper not containing the ultraviolet absorber was prepared to perform a similar test. The obtained results are plotted by a curve marked with D in Fig. 4.
As is obvious from this test, addition of a slight y amount of the ultraviolet absorber increases the resistance of the detector paper to light and alloias the paper to keep its detection sensitivivty intact over a long period of time,; without lowering the sensitivity to oxidizing gases.
[Example for Comparison]
For the purpose of comparison,, detector paper contain-ing an ultraviolet absorber and polyalcohol was prepared by using 4-hexyloxyaniline, which colors when coming.in con-tact with oxidizing.gases; as a reaction reagent. The i, sensitivity of the, paper to chlorine gas was examined after exposing it to light for.a,given length of time. A cuxve marked with in Fig. 4 shows the obtained results.
r'~"i r~ t.7 A curve marked with O in Fig. 4 shows the results of a similar test conducted on another specimen prepared without adding~the u7.traviolet absorber.
Obviously, ~-hexyloxyaniline, which colors on reacting with an oxidizing gas and thus causes changes in the opti-cal concentration of the detector paper, discolors when exposed to light even if an ultraviolet absorber is added, thereby lowering the sensitivity of the detector paper to axidizing gases.. As is .evident from this, p-n-butoxyani-line and p-methoxyaniline proved to be excellent reaction reagents that attain good resistance to light. Besides, .
the ultraviolet absorber proved to function effectively .
only in the presence of p-n-butoxyaniline or p-methoxyani;-line.
In addition to butylated hydroxytoluene used in the examples described before, such other ultraviolet absorbers as;butylated hydroxyanisole, hydroquinone, and 2,2'-methyl-enebis(4-methyl-~-butylphenol) also proued to increase the resi.stance.to light without decreasing the sensitivity to oxidizing gases.
Table T shows the results of an investigation on the relative outputs for other,oxidi.zing gases.
i°°'1 :~~6~13~
Table 1 Relative Output Kinds of Gases Concentration (R.I. %) Chlorine 0.5 ppm . 14.1 Ethanol 1.0 vol% < 1 Methanol 1.0 vol% < 1 Isopropyl alcohol1.0 vol% < 1 Acetone 1.0 vol% < 1 Trichloroethylene1.0 volo < 1 Toluene - 1.0 vol% < 1 Kylene 1.0 vol% < 1 Carbon diaxide 1.0 vol% < 1 Hydrogen 5:05 viols < 1 Nitrogen monoxide102.2 ppm < 1 Hydrogen sulfide 31.8 ppm < 1 Oxygen fluoride 10.0 ppm < 1 Sulfur oxide 51.5 ppm < 1 Acetylene 120.8 ppm < 1 Fluorine 5.0 ppm 4.1 Nitrogen dioxide 10.0 ppm 12.2 Ozone 4.0 ppm 3.3 Obviously, the oxidizing gas detector paper according to this invention proved to be sensitive to not only chlo-rine gas but also other oxidizing gases such as'fluorine, nitrogen dioxide and ozone. Meanwhile; it does not exhib-it, unlike the galvanic-cell .typ.e gas detectors, any un-wanted sensitivity to such organic solvents as ethanol and methanol; and nitrogen monoxide and hydrogen sulfide that i , can be readily released into, and are present in high con-centrations in, the environment. The oxidizing gas detec-tor paper of this invention proved to have an ability to detect chlorine and other oxidizing gases in the environ-ment with a nigh selectivity.
While cellulose-based paper is used as the carrier in the preferred embodiments, porous non-woven fabrics pre-pared from polymeric materials and other similar carriers will produce similar results.
Claims
To overcome this shortcoming, detector paper made by spreading a solution prepared by dissolving p-methoxyani-line, which colors on reaction with chlorine and other oxidizing gases, in a solvent over paper or.other carriers.
However, p-methoxyaniline tends to discolor when exposed to light. This discoloration resulting from expo- .
sure to light is difficult to distinguish from the coloring reaction with oxidizing gases that is used for the deter-urination of their concentration by optical means. This. can lead to the lowering of detection sensitivity.
Summary of the Invention To solve the problem described above, the oxidizing gas detector paper of this invention is prepared by spread-, ing p-n-butoxyaniline, an ultraviolet absorber and polyal-cohol.over a sheet of paper that serves as a carrier.
Object and Effect of the Invention The object of this invention is to provide.oxidizing gas detector paper that is immune to the interference of organic solvent, and other substances in the environment, has high resistance, to light and maintain a uniform.detec-tion sensitivity for a long period of t~.me.
Brief Description of the Drawings Fig. 1 is a cross-sectional view of an example of a measuring instrument that uses theyoxidizirig gas 'detector paper of this invention. Fig. 2 shows the measureznen'ts obtained by the oxidizing gas detector paper of this inven-tion, in which the concentration of chlorine gas is plot-ted, using the sampling time as a parameter. Fig. 3 shows the relationship between the reaction time of oxidizing gas detector. paper of this invention and changes in the concen-tration of an oxidizing gas, using the concentration of the oxidizing gas as a parameter. Fig. 4 graphically shows changes in the relative output obtained fram oxidizing gas detector paper of this invention exposed to light. Fig. 5 shows the relationship between the concentration of.a humectant and the relatiue output.
Description of the Preferred Embodiments Details of this invention' will be made.explicit in the following description of preferred, embodiments.
[example 1]
A reacting solution.of 100 milliliter was prepared by dissolving 1.0 gram of p-n-butoxyaniline, 1.7 gram of butylated liydroxyboluene as an ultraviolet absorber and 15 v/v o of polyalcohol, such as glycerin, as a humec~tant in metha~zol or other. organic' solvent.
A sheet of cellulose-based paper was immersed in the reacting solution thus prepared to allow the paper to i 'absorb the solution. The. paper lifted out of~the solution was passed through rollers of silicone rubber to squeeze out excess solution.. The squeezed paper was'allowed to stand in an environment at 40° C to allow the organic sol-vent to evaporate.
The oxidizing gas detector paper thus prepared con-tamed approximately 0.6 gram of p-n-butoxyaniline, appro-ximately 1.0 gram of butylated hydroxytoluene and 25 grams of glycerin per square meter.
Fig. 1 shows an, example of an instrument that dete-rmines the concentration of gas by using the oxidizing gas detector paper of this invention. In the drawing, refer-ence numeral 1 designates a gas suction device provided in the path of a tape of detector paper 2. The gas sucvtion device 1 has a through hole 3 having a diameter.of approxi-mately 1 cm that opens. in the surface thereof that faces the detector papex 2. A negative pressure, is supplied from a suction pump, not shown, through a pipe 4:
Reference numeral 5 denotes a measuring head disposed on the other side of the detector paper 2 opposite to the through hole 3 in the gas suction device 1. The measuring head 5 constitutes alight-shielding means having.a gas inlet 6 located in a position opposite. to the through hole 3 in the gas suction device 1. The measuring;head 5.con-tams'a light-emitting diode 7'emitting a Tight having~a peak wavelength;. of 555, nm and a pin-type photodiode 8 that exhsbits maximum sensitivity to'a light having a wavelength of 560 nm. ,The light-emitting diode 7 and,photodiode 8 are disposed in such a position that they can detect a trace of reaction formed on the detector paper 2.
After the tape of gas detector paper 2. is set over reels 10 and 1I, the suction pressure supplied from the pump not shown to the suction device 4 draws the object gas through an intake 9 to the measuring head 5. The object gas from the gas inlet 6 is discharged outside after pass-ing through the ;tape of detector paper 2 and 'the through hole 3. When the~object gas passes through the tape of detector paper 2, p-n-butoxyariiline on the tape 2 selec-tively reacts with an oXidi.zing gas to form a trace of reaction.
After sampling time.of,a given length,. such as appro-ximately 40 seconds; has passed, the suction of the object gas is stopped to determine the optical concentration of the trace of. reaction:
The light from the light-emitting diode 7 is absorbed according to the.optical concentration.of the trace of reaction formed on the surface o~ the tape. ;Therefore; the concentration or .the cumulative amount of the oxidizing gas that has passed.through the tape can.be obtained by deter-zniriing the difference between the opvtical concen~ratioi~s of the'tap~ before end after the suction of the object gas.
The optical concentration of the tape before.the .suction,i hat of the background of the tape:
When the measurement of one sampling is complete, the takeup reel 10 is turned to feed an unused portion of the tape 2 into the measuring zone.
Sample gases containing different concentrations of, chlorine gas were tested by setting the oxidizing gas detector paper of this invention on the device just de-scribed. Fig. 2 shows the obtained results.
In Fig. 2, curves L, II and III plot the measurements obtained with a sampling time of 20, 40 and 60 seconds, re-spectively. As evident from the figure, the oxidizing gas detector paper of this invention has sufficient sensitivity to oxidizing gases of as.low a concentration as approxi-matPly 0.l ppm. When the length of sampling time is in- .
creased, the amouyt of oxidizing gas working on the detec-for paper increases. This increase creates a cumulative effect to raise the optical concentration of gases of even lower concentrations, which,. in turn, permits measurement.
with high degrees of accuracy.
The optical concentrations of the traces of reaction formed by sample gases'I, II, III and III, each containing , 0.2, 0:5, 1.0 and 1.5 ppm of chlorine gas; were measured at given time intervals by varying their sampling time.. E'ig>, 3 shows the obtained results.
If a shorter sampling t~.me is set; the measurement of sample gases ITI and IV containing,higher concentrations of chlorine gas can be completed in a very short time.
With sample gases I and TI containing lower concentra-tions of chlorine gas, by comparison, the xelative output increases with an increase in the sampling t,~me.
Obviously, a wide range of concentrations of oxidizing Base can be measured by setting an appropriate sampling time suited for 'the concentration of each oxidizing gas to be detected.
The oxidizing gas detector paper described above was placed directly under and 30 cm away from a fluorescent lamp to irradiate a light of approximately 1500 lutes.
Chlorine gas of a fixed concentration was measured with the paper irradiated over different lengths of time. Then, the sensitivity of the paper irradiated for 6.hours did not drop substantially, as indicated by a curve marked with ~
in Fig. 4.
For the purpose of comparison, detector paper not containing the ultraviolet absorber was prepared to perform a similar test by using. chlorine gas of a fixed' conceritra-tion: Theri, the sensitivity of 'the. paper decreased with iricreasing,exposure time to light, as indicated by a curve .
marked with ~L1 in Fig. 4. I
As is obvious from this test, addition of the ultravi-olet absorber. increases the resistance of the detector paper to light, thereby allowing the'paper to keep its detection sensitivity intact over a long period of time.
While accelerating the reaction between the coloring reagent and oxidizing gas, the humectant has a great effect on the gas permeability of the detector paper because of its viscosity. Therefore, it can decrease the amount of the object gas passing through the paper, depending on the performance of the sampling pump of the gas detector..
Accordingly, there is a certain concentration,~that allows the paper to.exhibit the maximum sensitivity,.as,shown in Fig..5.
When the concentration of the humectant is low, there is less water that serves as.the medium for reaction. This decreases the speed of reaction between p-n-butoxyaniline and an oxidizing gas and, therefore, lowers the sensitivity of the detector paper. When the concentration. of the humectant in the prepared solution is between,2 and l5 v/v %, the sensitivity of the detector paper increases unvary-ingly with increasing concentration: When the concentra-tion ~~ceeds 15 v/v ~, the'detector paper allows an iri-creasingly sniall'quantity.of the object gas to pass through, thereby lowering the apparent sensitivity thereof.
Therefore; the quantity of the humectant carried,iby the detvector paper should preferably be limited between approximately 3 to 35 grams per square meter.y instead of glycerin used in this: embodiment; other po~.yalcohoi, such T
as ethylene glycol, may be used as the humectant to obtain a similar effect.
[Example 2]
A reacting solution of 100 milliliter was -prepared by dissolving 1,0 gram of p-methoxyaniline, 1.7 gram of butyl-ated hydroxytoluene as an ultraviolet absorber and 15 v/v o of polyalcohol, such as glycerin, as a humectant in metha-nol or other organic solvent.
A sheet of cellulose-based paper was immersed in the reacting solution thus prepared to allow the paper to absorb the solution: The paper lifted out of the solution was; passed through rollers of silicone rubber to squeeze out excess solution. The squeezed paper was allowed to stand in an 2nVironment at 40° C to allow the organic sol-vent.to evaporate.
The oxidizing gas detector paper thus prepared con-tained approximately 0.6 gram of p-m.ethoxyaniline, appro-ximately 1.O gram of butylated hydroxytoluene and 25 grams of glycerin per square meter:
By using the gasdetector paper thus obtained, and the samp,li.ng'time and the concentration of oxidizing gas, respectively, as a parameter,v the obtained measurement's and relationship between sampling 'time and the concentration of the'trace of reaction were investigated, as in the case of the:first example described before. 'The results were substantially similar to those obtained in the first exam-ple.
The oxidizing gas detector paper described above was.
placed directly under and 30 cm away from a fluorescent lamp to irradiate a light of approximately 1500 luces.
Chlorine gas of a fixed concentration was measured,with the paper irradiated over different lengths of time. A curve marked with in Fig. 4 plots the results obtained.
For the purpose of comparison, detector paper not containing the ultraviolet absorber was prepared to perform a similar test. The obtained results are plotted by a curve marked with D in Fig. 4.
As is obvious from this test, addition of a slight y amount of the ultraviolet absorber increases the resistance of the detector paper to light and alloias the paper to keep its detection sensitivivty intact over a long period of time,; without lowering the sensitivity to oxidizing gases.
[Example for Comparison]
For the purpose of comparison,, detector paper contain-ing an ultraviolet absorber and polyalcohol was prepared by using 4-hexyloxyaniline, which colors when coming.in con-tact with oxidizing.gases; as a reaction reagent. The i, sensitivity of the, paper to chlorine gas was examined after exposing it to light for.a,given length of time. A cuxve marked with in Fig. 4 shows the obtained results.
r'~"i r~ t.7 A curve marked with O in Fig. 4 shows the results of a similar test conducted on another specimen prepared without adding~the u7.traviolet absorber.
Obviously, ~-hexyloxyaniline, which colors on reacting with an oxidizing gas and thus causes changes in the opti-cal concentration of the detector paper, discolors when exposed to light even if an ultraviolet absorber is added, thereby lowering the sensitivity of the detector paper to axidizing gases.. As is .evident from this, p-n-butoxyani-line and p-methoxyaniline proved to be excellent reaction reagents that attain good resistance to light. Besides, .
the ultraviolet absorber proved to function effectively .
only in the presence of p-n-butoxyaniline or p-methoxyani;-line.
In addition to butylated hydroxytoluene used in the examples described before, such other ultraviolet absorbers as;butylated hydroxyanisole, hydroquinone, and 2,2'-methyl-enebis(4-methyl-~-butylphenol) also proued to increase the resi.stance.to light without decreasing the sensitivity to oxidizing gases.
Table T shows the results of an investigation on the relative outputs for other,oxidi.zing gases.
i°°'1 :~~6~13~
Table 1 Relative Output Kinds of Gases Concentration (R.I. %) Chlorine 0.5 ppm . 14.1 Ethanol 1.0 vol% < 1 Methanol 1.0 vol% < 1 Isopropyl alcohol1.0 vol% < 1 Acetone 1.0 vol% < 1 Trichloroethylene1.0 volo < 1 Toluene - 1.0 vol% < 1 Kylene 1.0 vol% < 1 Carbon diaxide 1.0 vol% < 1 Hydrogen 5:05 viols < 1 Nitrogen monoxide102.2 ppm < 1 Hydrogen sulfide 31.8 ppm < 1 Oxygen fluoride 10.0 ppm < 1 Sulfur oxide 51.5 ppm < 1 Acetylene 120.8 ppm < 1 Fluorine 5.0 ppm 4.1 Nitrogen dioxide 10.0 ppm 12.2 Ozone 4.0 ppm 3.3 Obviously, the oxidizing gas detector paper according to this invention proved to be sensitive to not only chlo-rine gas but also other oxidizing gases such as'fluorine, nitrogen dioxide and ozone. Meanwhile; it does not exhib-it, unlike the galvanic-cell .typ.e gas detectors, any un-wanted sensitivity to such organic solvents as ethanol and methanol; and nitrogen monoxide and hydrogen sulfide that i , can be readily released into, and are present in high con-centrations in, the environment. The oxidizing gas detec-tor paper of this invention proved to have an ability to detect chlorine and other oxidizing gases in the environ-ment with a nigh selectivity.
While cellulose-based paper is used as the carrier in the preferred embodiments, porous non-woven fabrics pre-pared from polymeric materials and other similar carriers will produce similar results.
Claims
Claims
What is claimed is:
(1) Oxidizing gas detector paper prepared by spreading p-n-butoxyaniline, an ultraviolet absorber and polyalcohol over a sheet of paper.
(2) Oxidizing gas detector paper prepared by spreading p-methoxyaniline, an ultraviolet absorber and polyalcohol over a sheet of paper.
(3) Oxidizing gas detector paper according to claim 1 or 2, in which the ultraviolet absorber is selected from a group of butylated hydroxytoluene, butylated hydroxyanis-ole, hydroquinone, and 2,2'-methylenebis(4-methyl-6-buty-lphenol).
(1) Oxidizing gas detector paper prepared by spreading p-n-butoxyaniline, an ultraviolet absorber and polyalcohol over a sheet of paper.
(2) Oxidizing gas detector paper prepared by spreading p-methoxyaniline, an ultraviolet absorber and polyalcohol over a sheet of paper.
(3) Oxidizing gas detector paper according to claim 1 or 2, in which the ultraviolet absorber is selected from a group of butylated hydroxytoluene, butylated hydroxyanis-ole, hydroquinone, and 2,2'-methylenebis(4-methyl-6-buty-lphenol).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05180944A JP3092685B2 (en) | 1993-06-25 | 1993-06-25 | Oxidizing gas detection tape |
| JP180944/1993 | 1993-06-25 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2126738A1 CA2126738A1 (en) | 1994-12-26 |
| CA2126738C true CA2126738C (en) | 2004-10-12 |
Family
ID=16092012
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2126738 Expired - Fee Related CA2126738C (en) | 1993-06-25 | 1994-06-24 | Oxidizing gas detector paper |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP3092685B2 (en) |
| CA (1) | CA2126738C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7054759B2 (en) | 2001-12-27 | 2006-05-30 | Arkray, Inc | Concentration measuring method |
| JP2006112914A (en) * | 2004-10-14 | 2006-04-27 | Riken Keiki Co Ltd | Chlorine gas sensing material |
| WO2008041712A1 (en) * | 2006-10-02 | 2008-04-10 | Nippon Telegraph And Telephone Corporation | Ozone-detecting element |
| JP4880425B2 (en) * | 2006-11-07 | 2012-02-22 | 日本電信電話株式会社 | Ozone detector |
-
1993
- 1993-06-25 JP JP05180944A patent/JP3092685B2/en not_active Expired - Lifetime
-
1994
- 1994-06-24 CA CA 2126738 patent/CA2126738C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2126738A1 (en) | 1994-12-26 |
| JPH0712733A (en) | 1995-01-17 |
| JP3092685B2 (en) | 2000-09-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20140625 |