CA2132413C - Basic-gas detection paper - Google Patents
Basic-gas detection paper Download PDFInfo
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- CA2132413C CA2132413C CA 2132413 CA2132413A CA2132413C CA 2132413 C CA2132413 C CA 2132413C CA 2132413 CA2132413 CA 2132413 CA 2132413 A CA2132413 A CA 2132413A CA 2132413 C CA2132413 C CA 2132413C
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- Prior art keywords
- paper
- basic
- fluorescein
- gas detection
- gas
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- Expired - Lifetime
Links
- 238000001514 detection method Methods 0.000 title claims description 34
- GNBHRKFJIUUOQI-UHFFFAOYSA-N fluorescein Chemical compound O1C(=O)C2=CC=CC=C2C21C1=CC=C(O)C=C1OC1=CC(O)=CC=C21 GNBHRKFJIUUOQI-UHFFFAOYSA-N 0.000 claims abstract description 18
- 150000007524 organic acids Chemical class 0.000 claims abstract description 10
- 239000003906 humectant Substances 0.000 claims abstract description 9
- 241000220317 Rosa Species 0.000 claims description 7
- -1 benzal Chemical class 0.000 claims description 7
- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 claims description 7
- SEACYXSIPDVVMV-UHFFFAOYSA-L eosin Y Chemical compound [Na+].[Na+].[O-]C(=O)C1=CC=CC=C1C1=C2C=C(Br)C(=O)C(Br)=C2OC2=C(Br)C([O-])=C(Br)C=C21 SEACYXSIPDVVMV-UHFFFAOYSA-L 0.000 claims description 6
- 229940057841 eosine yellowish Drugs 0.000 claims description 5
- GVKCHTBDSMQENH-UHFFFAOYSA-L phloxine B Chemical compound [Na+].[Na+].[O-]C(=O)C1=C(Cl)C(Cl)=C(Cl)C(Cl)=C1C1=C2C=C(Br)C(=O)C(Br)=C2OC2=C(Br)C([O-])=C(Br)C=C21 GVKCHTBDSMQENH-UHFFFAOYSA-L 0.000 claims description 5
- 150000005846 sugar alcohols Polymers 0.000 claims description 4
- OOYIOIOOWUGAHD-UHFFFAOYSA-L disodium;2',4',5',7'-tetrabromo-4,5,6,7-tetrachloro-3-oxospiro[2-benzofuran-1,9'-xanthene]-3',6'-diolate Chemical compound [Na+].[Na+].O1C(=O)C(C(=C(Cl)C(Cl)=C2Cl)Cl)=C2C21C1=CC(Br)=C([O-])C(Br)=C1OC1=C(Br)C([O-])=C(Br)C=C21 OOYIOIOOWUGAHD-UHFFFAOYSA-L 0.000 claims description 3
- SRSXLGNVWSONIS-UHFFFAOYSA-N benzenesulfonic acid Chemical compound OS(=O)(=O)C1=CC=CC=C1 SRSXLGNVWSONIS-UHFFFAOYSA-N 0.000 claims description 2
- PSZYNBSKGUBXEH-UHFFFAOYSA-N naphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(S(=O)(=O)O)=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-N 0.000 claims description 2
- IINNWAYUJNWZRM-UHFFFAOYSA-L erythrosin B Chemical compound [Na+].[Na+].[O-]C(=O)C1=CC=CC=C1C1=C2C=C(I)C(=O)C(I)=C2OC2=C(I)C([O-])=C(I)C=C21 IINNWAYUJNWZRM-UHFFFAOYSA-L 0.000 claims 1
- 229940011411 erythrosine Drugs 0.000 claims 1
- 235000012732 erythrosine Nutrition 0.000 claims 1
- 239000004174 erythrosine Substances 0.000 claims 1
- 239000007789 gas Substances 0.000 abstract description 50
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 abstract description 14
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 24
- 238000006243 chemical reaction Methods 0.000 description 16
- 239000000243 solution Substances 0.000 description 15
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 13
- 239000012298 atmosphere Substances 0.000 description 13
- 229960002143 fluorescein Drugs 0.000 description 13
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 12
- 239000000975 dye Substances 0.000 description 12
- 235000011187 glycerol Nutrition 0.000 description 12
- 230000035945 sensitivity Effects 0.000 description 11
- 230000003287 optical effect Effects 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical group Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- 238000005070 sampling Methods 0.000 description 6
- 229910021529 ammonia Inorganic materials 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 239000003960 organic solvent Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 208000007542 Paresis Diseases 0.000 description 4
- 208000012318 pareses Diseases 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 150000001412 amines Chemical class 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 238000002845 discoloration Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- LBLYYCQCTBFVLH-UHFFFAOYSA-N 2-Methylbenzenesulfonic acid Chemical compound CC1=CC=CC=C1S(O)(=O)=O LBLYYCQCTBFVLH-UHFFFAOYSA-N 0.000 description 1
- AMPRUHSMBLJPAM-UHFFFAOYSA-N 4-(2-phenylethenyl)benzenesulfonic acid Chemical compound C1=CC(S(=O)(=O)O)=CC=C1C=CC1=CC=CC=C1 AMPRUHSMBLJPAM-UHFFFAOYSA-N 0.000 description 1
- 210000005056 cell body Anatomy 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000007850 degeneration Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- QGAYMQGSQUXCQO-UHFFFAOYSA-L eosin b Chemical compound [Na+].[Na+].O1C(=O)C2=CC=CC=C2C21C1=CC([N+]([O-])=O)=C([O-])C(Br)=C1OC1=C2C=C([N+]([O-])=O)C([O-])=C1Br QGAYMQGSQUXCQO-UHFFFAOYSA-L 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- SXQCTESRRZBPHJ-UHFFFAOYSA-M lissamine rhodamine Chemical compound [Na+].C=12C=CC(=[N+](CC)CC)C=C2OC2=CC(N(CC)CC)=CC=C2C=1C1=CC=C(S([O-])(=O)=O)C=C1S([O-])(=O)=O SXQCTESRRZBPHJ-UHFFFAOYSA-M 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229940057952 methanol Drugs 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000036647 reaction Effects 0.000 description 1
- AZJPTIGZZTZIDR-UHFFFAOYSA-L rose bengal Chemical compound [K+].[K+].[O-]C(=O)C1=C(Cl)C(Cl)=C(Cl)C(Cl)=C1C1=C2C=C(I)C(=O)C(I)=C2OC2=C(I)C([O-])=C(I)C=C21 AZJPTIGZZTZIDR-UHFFFAOYSA-L 0.000 description 1
- 229960003138 rose bengal sodium Drugs 0.000 description 1
Landscapes
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
- Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
Abstract
A sheet of paper is impregnated with a fluorescein-based dye and a strong organic acid together with a humectant In the presence of the strong organic acid, the normally colored fluorescein-based dye remains colorless on the paper. When a basic gas dissolved in the moisture held by the humectant turns the pH of the paper to the alkaline side, fluorescein-based dye takes on color in accordance with the hydrogen ion concentration. The concentration of the basic gas can be determined by measuring the degree of this coloration.
Description
2~.32~~13 SPECIFICATION
Title of the Invention Basic-gas Detection Paper Background of the Invention This invention relates to basic gas detection paper that detects ammonia, amines and other basin gases present in the atmosphere and other gases by means of coloring reaction.
Description of the Prior Art The presence of ammonia, amines and other basic gases in the atmosphere is usually detected by using a hydrogen ion concentration sensor comprising glass electrodes im-mersed in the electrolyte. However, this type of sensor requires considerably demanding maintenance, such as the frequent replacement of the electrolyte. This replacement is necessary because the sensitivity to basic gases of low concentrations drops sharply when 'the reference hydrogen ion concentration of the electrolyte changes under the influence of acid gases present in the atmosphere.
On the other hand, fluorescein test paper, which is prepared by dyeing paper with a neutral solution of fluo-resdein, is used as a handy means for identifying some specific gas contained in a gas mixture with high sensitiv-ity. However, fluorescein test paper does not have high enough sensitivity to detect basic gases i.n the atmosphere 2132~1~
or other gases, is highly susceptible to discoloration in the atmosphere, and, therefore, is unsuited for such appli-rations as 'the collection of environmental data in which the test paper must be left in the atmosphere for a long period of time.
Summary of the Invention The basic-gas detection paper according to -this inven-Lion carries a fluorescein-based dye and a strong organic acid thereon, together with a humectant. A fluorescein-based dye, which has a valor when it exists singly, is calorless in the presence of a strong organic acid. When the basic gas to be examined is exposed to the moisture held by the humectant and thus makes the paper alkaline, the fluorescein-based dye colors according to the concen-tration of hydrogen ion.
A first object of this invention is to pravide high-sensitivity basic-gas detection paper that can detect basic gases of the order of ppb (parts per billion) present in various kinds of gases.
A second object of this invention is to provide basic-gas detection paper that does not discolor in 'the atma-sphere and maintains stable sensitivity over a long period of time.
Carrying a fluorescein-based dye and a strong organic acid together with a humectant, the basic-gas detection paper according to this invention can detect ammonia, amines and other basic gases of as low concentrations as of the order of 100 ppb. The organic acid of high molecular weight used as the hydrogen ion concentration adjuster pre-vents the deterioration of the carrier during long storage, keeps the hydrogen ion concentration at a constant level, prevents discoloration that can otherwise result from exposure to the atmasphere, and maintains stable sensitivity over a long period of time. Accordingly, -the basic-gas detection paper according to this invention is very suitable for such applications as the collection of environmental data that may last long.
Brief Description of the Drawings Fig. 1 shows an example of an apparatus suited for using a tape of the gas detection paper according to -this invention.
Fig. 2 graphically shows the concentration of ammonia, which is a kind of basic gases, measured by the gas detec-~tion paper according to this invention.
Description of the Preferred Embodiments [Example 1]
A reaction solution is prepared by dissolving 0.05 weight percent of rose benzal (CZOHzCI4Naz05; solar index:
acid red 94), which is a fluorescein-based dye, 1.5 weight percent of para-toluenesulfonic acid, and 15 volume percent 2132~~.~
.1 of polyhydric alcohol, such as glycerin, in water or an organic solvent such as methanol.
Some suitable organic solvent should preferably be used to shorten 'the drying time.
A sheet of paper is immersed in a bath of the prepared reaction solution. The paper impregnated with the reaction solution is pulled out of the bath to air-dry the solvent.
The sheet of paper thus carrying rose benzal, para-toluenesulfonic acid and glycerin 'thereon is slit into a tape or other form suited for use on a measuring apparatus.
On absorbing the moisture in the atmosphere, the glycerin contained in the paper forms an aqueous solution of pare--toluenesulfonic acid, thus keeping -the hydrogen ion concentration at approximately pH 1 to pH 2. Therefore, the rose benzal becomes substantially colorless and trans-parent. As a consequence, 'the color of the detection paper is the same as that of the base paper :itself before it is exposed to the gas to be examined.
Fig. 1 shows an example of a measuring apparatus suited :Eor the use of the gas detection paper described above. Reference numeral 1 designates a gas suction unit facing a path in which a gas detection tape 2 travels, with a through hole having a diameter of approximately 1 cm opening in the surface thereof opposite the tape 2. A
negative pressure created by a suction pump not shown works i"°~
thereat through a pipe 4.
Reference numeral 5 denotes a measuring head located opposite 'the through hole 3 in the gas suction unit 1 on the other side of the gas detection tape 2. The measuring head 5 constitutes a light-shielded container having a through hale 6 opposite the through hole 3 in the suction unit 1. The measuring head 5 contains a light-emitting diode 7 having a peak wavelength of 555 nm and a pin-type photodiode 8 that exhibits the highest sensitivity to a light having a wavelength of 560 nm that are disposed in such a configuration that they can determine the optical concentration of the trace of reaction formed on the tape 2.
With a tape slit from the detection paper passed over reels 10 and 11, a suction pressure from a pump not shown is introduced to tho pipe 4 connected to the suction unit 1 to draw in a specimen gas through, a specimen gas inlet 9.
The gas passes from 'the -through hole 6, through -the detec-tion tape 2, and then outside ~thraugh the through hole 3.
With the tape passed over the reels 10 and 11, to be more specific, the suction pressure from the pump not shown is introduced to the pipe 4 over a sampling period of 30 seconds at a sampling rate of 400 milliliters per minute.
Then, the specimen gas is drawn into the measuring head 5 -through the inlet 9.
The gas passes from the through hole 6, through the detection tape 2, and then outside through the through hole 3. When the gas passes through the detection tape 2, the moisture held by the glycerin thereon captures the ammonia contained in the gas, whereupon the hydrogen ion concentra-tion 'turns to the alkaline side. With this change, the rose benzal that has been colorless and transparent takes on color in accordance with the hydrogen ion concentration.
When the sampling period of 30 seconds is over, the suction of the specimen gas is stopped to start the meas-urement of the optical concentration of the trace of reac-tion formed on the surface of the tape. The light from the light-emitting diode 7 is absorbed in proportion to the optical concentration of the trace of reaction formed.
Therefore, the cancentration of ammonia gas can be deter-mined by obtaining the difference between the optical concentration bofore the start of measurement or 'the opti-cal concentration of the background of the tape and the optical concentration of 'the 'trace of .reaction. When 'the measurement of one sampled unit of gas is complete, the take-up reel 11 is moved to feed an unused part of the tape into the measuring zone.
Changes in the optical concentration of the trace of reaotion was measured by using the detection tape set on the measuring apparatus described above while changing the 213~~~3 concentration of ammonia gas. Curve I in Fig. 2 shows the measurements obtained with a sampling period of approxi-mately 30 seconds. The detection paper proved to be capa-ble of detecting ammonia gas in the atmosphere with a high linearity and a high sensitivity of the order of 100 ppm.
Curve II in Fig. 2 shows the measurements obtained with a sampling period of 60 seconds. The outputs plotted by curve II are approximately twice greater than those of curve I.
When the sampling period is extended, as is obvious from these two curves, the detention paper according to this invention detects gases of extremely low concentra-tions because of the cumulative effect of the lengthened time.
The reaction solution used in the example just de-scribed is prepared by dissolving all ingredients in the organic solvent. However, soma of them, such as pares-tol-uenesulfonic acid alorxe, may be dissolved in water before-hand. Then, the prepared aqueous solution of pares-~toluene-sulfonic acid is added to a solution prepared by dissolving rose benzal and glycerin in alcohol. This method facili-testes the adjustment of the hydrogen ion concentration of the reaction solution.
[Example 2]
A reaction solution is prepared by dissolving 0.1 _, 2132413 weight percent of phloxine (CZOH205Br4C1nNa?; color index:
acid red 92), which is a fluorescein-based dye, 0.3 weight percent of para-toluenesulfonic acid, and 15 volume percent of polyhydric alcohol, such as glycerin, in water or an organic solvent such as methanol.
A sheet of paper is immersed in a bath of the prepared reaction solution. The paper impregnated with the reaction solution is pulled out of the bath to air-dry the solvent.
The sheet of paper thus carrying phloxine, para-tol-uenesulfonic acid and glycerin thereon is slit iwto a tape or other form suited for use on a measuring apparatus.
On absorbing the moisture in the atmosphere, the glycerin contained in the paper forms an aqueous solution of para-toluenesulfonic acid, thus keeping the hydrogen ion concentration at approximately pH 1 to pH 2. Therefore, the phloxine becomes substantially colorless and transpar-ent. As a consequence, the co7.or of the detectian paper is the same as that of 'the base paper itself before it is exposed to the gas to be examined.
[Example 3a A reaction solution is prepared by dissolving 0.1 weight percent of eosine yellowish ( CZOH60~Br4Na2; color index: acid red 87), which is a fluorescein-based dye, 0.3 weight percent of para-toluenesulfonic acid, and 15 volume percent of polyhydri.c alcohol, such as glycerin, in water '1 2~.32~~~3 or an organic solvent such as methanol.
A sheet of paper of such substance as cellulose having a high affinity for water and a high acid resistance is im-mersed in a bath of the prepared reaction solution to impregnate it with the ingredients of the solution.
The paper impregnated with the reaction solution is then pulled out of the bath to air-dry the solvent metha-nol. Thus, a sheet of paper carrying eosine yellowish, para-toluenesulfonic said and glycerin thereon is obtained.
On absorbing the moisture in the atmosphere, the glycerin contained in the paper forms an agueous solution of para-toluenesulfonic acid, thus keeping the hydrogen ion concentration at approximately pH 1 to pH 2. Therefore, the eosine yellowish becomes substantially transparent and very pale pink in color.
The gas detection paper is usually stored in gas-tight containers as their proper~tios change when the ingredients carried thereon react with 'the constituents of the atmos-phere. During use, however, degeneration is likely to occur because the gas detection paper is taken out of such containers and put an measuring devices exposed to the atmosphere.
When placed in the atmosphere not exposed to light far several days,however, the gas detection paper according to this invention neither discolored nor underwent any changes ..
2132~.~3 in detection sensitivity.
Another gas detection paper was prepared by a similar method, except that pares-toluenesulfonic acid was replaced with hydrochloric acid -that seldom deteriorates cellulose.
When subjected to the same test, however, the hydrochloric acid volatilized, -the paper discolored in less than one hour, and its detection sensitivity dropped with time.
Thus, the use of pares-toluenesulfonic acid proved to be very beneficial to the lengthening of the shelf life of the gas detection paper.
As has been mentioned, the fluorescein-based dye carried by the gas detection paper of this invention nor-molly remains substantially colorless, but takes on color when it comes in contact with the specimen gas to be exam-ined. There-fore, the detection sensitivity of the paper increases as the concentration of the dye carried thereon increases. However, -the concentration of the fluorescein-based dye should be such that the coloration -thereof can be controlled by means of a strong organic acid and no precipitation thereof occurs on the paper.
Instead of the rose benzal, phloxine and eosine yel-lowish used in -the examples described before, other fluo-rescein-based dyes, such as eosine bluish (CZOH6Hr2C1NaZO9;
color index: acid red 91) and erythrasine (CZ~HZ9Nz0~Sz%
color index: acid red 52) may also be used. The detection _, ~132~13 paper prepared with such other fluorescein-based dyes proved to be capable of detecting basic gases with practi-cal accuracy, though the detection sensitivity is somewhat more susceptible to variations.
In the examples described before, pare-toluenesulfonic acid is used as the hydrogen ion concentration adjuster.
Other strong organic acids, such as naphthalenesulfonic acid and benzensulfonic acid, also proved to be much more beneficial than hydrochloric acid in the lengthening of the shelf life of the detention paper.
Furthermore, glycerin, which is used as the humectant, may also be replaced with other substances that do not change the hydrogen ion concentration, such as ethylene glycol and polyalcohol. The paper prepared with such humectants also produce similar effects.
Title of the Invention Basic-gas Detection Paper Background of the Invention This invention relates to basic gas detection paper that detects ammonia, amines and other basin gases present in the atmosphere and other gases by means of coloring reaction.
Description of the Prior Art The presence of ammonia, amines and other basic gases in the atmosphere is usually detected by using a hydrogen ion concentration sensor comprising glass electrodes im-mersed in the electrolyte. However, this type of sensor requires considerably demanding maintenance, such as the frequent replacement of the electrolyte. This replacement is necessary because the sensitivity to basic gases of low concentrations drops sharply when 'the reference hydrogen ion concentration of the electrolyte changes under the influence of acid gases present in the atmosphere.
On the other hand, fluorescein test paper, which is prepared by dyeing paper with a neutral solution of fluo-resdein, is used as a handy means for identifying some specific gas contained in a gas mixture with high sensitiv-ity. However, fluorescein test paper does not have high enough sensitivity to detect basic gases i.n the atmosphere 2132~1~
or other gases, is highly susceptible to discoloration in the atmosphere, and, therefore, is unsuited for such appli-rations as 'the collection of environmental data in which the test paper must be left in the atmosphere for a long period of time.
Summary of the Invention The basic-gas detection paper according to -this inven-Lion carries a fluorescein-based dye and a strong organic acid thereon, together with a humectant. A fluorescein-based dye, which has a valor when it exists singly, is calorless in the presence of a strong organic acid. When the basic gas to be examined is exposed to the moisture held by the humectant and thus makes the paper alkaline, the fluorescein-based dye colors according to the concen-tration of hydrogen ion.
A first object of this invention is to pravide high-sensitivity basic-gas detection paper that can detect basic gases of the order of ppb (parts per billion) present in various kinds of gases.
A second object of this invention is to provide basic-gas detection paper that does not discolor in 'the atma-sphere and maintains stable sensitivity over a long period of time.
Carrying a fluorescein-based dye and a strong organic acid together with a humectant, the basic-gas detection paper according to this invention can detect ammonia, amines and other basic gases of as low concentrations as of the order of 100 ppb. The organic acid of high molecular weight used as the hydrogen ion concentration adjuster pre-vents the deterioration of the carrier during long storage, keeps the hydrogen ion concentration at a constant level, prevents discoloration that can otherwise result from exposure to the atmasphere, and maintains stable sensitivity over a long period of time. Accordingly, -the basic-gas detection paper according to this invention is very suitable for such applications as the collection of environmental data that may last long.
Brief Description of the Drawings Fig. 1 shows an example of an apparatus suited for using a tape of the gas detection paper according to -this invention.
Fig. 2 graphically shows the concentration of ammonia, which is a kind of basic gases, measured by the gas detec-~tion paper according to this invention.
Description of the Preferred Embodiments [Example 1]
A reaction solution is prepared by dissolving 0.05 weight percent of rose benzal (CZOHzCI4Naz05; solar index:
acid red 94), which is a fluorescein-based dye, 1.5 weight percent of para-toluenesulfonic acid, and 15 volume percent 2132~~.~
.1 of polyhydric alcohol, such as glycerin, in water or an organic solvent such as methanol.
Some suitable organic solvent should preferably be used to shorten 'the drying time.
A sheet of paper is immersed in a bath of the prepared reaction solution. The paper impregnated with the reaction solution is pulled out of the bath to air-dry the solvent.
The sheet of paper thus carrying rose benzal, para-toluenesulfonic acid and glycerin 'thereon is slit into a tape or other form suited for use on a measuring apparatus.
On absorbing the moisture in the atmosphere, the glycerin contained in the paper forms an aqueous solution of pare--toluenesulfonic acid, thus keeping -the hydrogen ion concentration at approximately pH 1 to pH 2. Therefore, the rose benzal becomes substantially colorless and trans-parent. As a consequence, 'the color of the detection paper is the same as that of the base paper :itself before it is exposed to the gas to be examined.
Fig. 1 shows an example of a measuring apparatus suited :Eor the use of the gas detection paper described above. Reference numeral 1 designates a gas suction unit facing a path in which a gas detection tape 2 travels, with a through hole having a diameter of approximately 1 cm opening in the surface thereof opposite the tape 2. A
negative pressure created by a suction pump not shown works i"°~
thereat through a pipe 4.
Reference numeral 5 denotes a measuring head located opposite 'the through hole 3 in the gas suction unit 1 on the other side of the gas detection tape 2. The measuring head 5 constitutes a light-shielded container having a through hale 6 opposite the through hole 3 in the suction unit 1. The measuring head 5 contains a light-emitting diode 7 having a peak wavelength of 555 nm and a pin-type photodiode 8 that exhibits the highest sensitivity to a light having a wavelength of 560 nm that are disposed in such a configuration that they can determine the optical concentration of the trace of reaction formed on the tape 2.
With a tape slit from the detection paper passed over reels 10 and 11, a suction pressure from a pump not shown is introduced to tho pipe 4 connected to the suction unit 1 to draw in a specimen gas through, a specimen gas inlet 9.
The gas passes from 'the -through hole 6, through -the detec-tion tape 2, and then outside ~thraugh the through hole 3.
With the tape passed over the reels 10 and 11, to be more specific, the suction pressure from the pump not shown is introduced to the pipe 4 over a sampling period of 30 seconds at a sampling rate of 400 milliliters per minute.
Then, the specimen gas is drawn into the measuring head 5 -through the inlet 9.
The gas passes from the through hole 6, through the detection tape 2, and then outside through the through hole 3. When the gas passes through the detection tape 2, the moisture held by the glycerin thereon captures the ammonia contained in the gas, whereupon the hydrogen ion concentra-tion 'turns to the alkaline side. With this change, the rose benzal that has been colorless and transparent takes on color in accordance with the hydrogen ion concentration.
When the sampling period of 30 seconds is over, the suction of the specimen gas is stopped to start the meas-urement of the optical concentration of the trace of reac-tion formed on the surface of the tape. The light from the light-emitting diode 7 is absorbed in proportion to the optical concentration of the trace of reaction formed.
Therefore, the cancentration of ammonia gas can be deter-mined by obtaining the difference between the optical concentration bofore the start of measurement or 'the opti-cal concentration of the background of the tape and the optical concentration of 'the 'trace of .reaction. When 'the measurement of one sampled unit of gas is complete, the take-up reel 11 is moved to feed an unused part of the tape into the measuring zone.
Changes in the optical concentration of the trace of reaotion was measured by using the detection tape set on the measuring apparatus described above while changing the 213~~~3 concentration of ammonia gas. Curve I in Fig. 2 shows the measurements obtained with a sampling period of approxi-mately 30 seconds. The detection paper proved to be capa-ble of detecting ammonia gas in the atmosphere with a high linearity and a high sensitivity of the order of 100 ppm.
Curve II in Fig. 2 shows the measurements obtained with a sampling period of 60 seconds. The outputs plotted by curve II are approximately twice greater than those of curve I.
When the sampling period is extended, as is obvious from these two curves, the detention paper according to this invention detects gases of extremely low concentra-tions because of the cumulative effect of the lengthened time.
The reaction solution used in the example just de-scribed is prepared by dissolving all ingredients in the organic solvent. However, soma of them, such as pares-tol-uenesulfonic acid alorxe, may be dissolved in water before-hand. Then, the prepared aqueous solution of pares-~toluene-sulfonic acid is added to a solution prepared by dissolving rose benzal and glycerin in alcohol. This method facili-testes the adjustment of the hydrogen ion concentration of the reaction solution.
[Example 2]
A reaction solution is prepared by dissolving 0.1 _, 2132413 weight percent of phloxine (CZOH205Br4C1nNa?; color index:
acid red 92), which is a fluorescein-based dye, 0.3 weight percent of para-toluenesulfonic acid, and 15 volume percent of polyhydric alcohol, such as glycerin, in water or an organic solvent such as methanol.
A sheet of paper is immersed in a bath of the prepared reaction solution. The paper impregnated with the reaction solution is pulled out of the bath to air-dry the solvent.
The sheet of paper thus carrying phloxine, para-tol-uenesulfonic acid and glycerin thereon is slit iwto a tape or other form suited for use on a measuring apparatus.
On absorbing the moisture in the atmosphere, the glycerin contained in the paper forms an aqueous solution of para-toluenesulfonic acid, thus keeping the hydrogen ion concentration at approximately pH 1 to pH 2. Therefore, the phloxine becomes substantially colorless and transpar-ent. As a consequence, the co7.or of the detectian paper is the same as that of 'the base paper itself before it is exposed to the gas to be examined.
[Example 3a A reaction solution is prepared by dissolving 0.1 weight percent of eosine yellowish ( CZOH60~Br4Na2; color index: acid red 87), which is a fluorescein-based dye, 0.3 weight percent of para-toluenesulfonic acid, and 15 volume percent of polyhydri.c alcohol, such as glycerin, in water '1 2~.32~~~3 or an organic solvent such as methanol.
A sheet of paper of such substance as cellulose having a high affinity for water and a high acid resistance is im-mersed in a bath of the prepared reaction solution to impregnate it with the ingredients of the solution.
The paper impregnated with the reaction solution is then pulled out of the bath to air-dry the solvent metha-nol. Thus, a sheet of paper carrying eosine yellowish, para-toluenesulfonic said and glycerin thereon is obtained.
On absorbing the moisture in the atmosphere, the glycerin contained in the paper forms an agueous solution of para-toluenesulfonic acid, thus keeping the hydrogen ion concentration at approximately pH 1 to pH 2. Therefore, the eosine yellowish becomes substantially transparent and very pale pink in color.
The gas detection paper is usually stored in gas-tight containers as their proper~tios change when the ingredients carried thereon react with 'the constituents of the atmos-phere. During use, however, degeneration is likely to occur because the gas detection paper is taken out of such containers and put an measuring devices exposed to the atmosphere.
When placed in the atmosphere not exposed to light far several days,however, the gas detection paper according to this invention neither discolored nor underwent any changes ..
2132~.~3 in detection sensitivity.
Another gas detection paper was prepared by a similar method, except that pares-toluenesulfonic acid was replaced with hydrochloric acid -that seldom deteriorates cellulose.
When subjected to the same test, however, the hydrochloric acid volatilized, -the paper discolored in less than one hour, and its detection sensitivity dropped with time.
Thus, the use of pares-toluenesulfonic acid proved to be very beneficial to the lengthening of the shelf life of the gas detection paper.
As has been mentioned, the fluorescein-based dye carried by the gas detection paper of this invention nor-molly remains substantially colorless, but takes on color when it comes in contact with the specimen gas to be exam-ined. There-fore, the detection sensitivity of the paper increases as the concentration of the dye carried thereon increases. However, -the concentration of the fluorescein-based dye should be such that the coloration -thereof can be controlled by means of a strong organic acid and no precipitation thereof occurs on the paper.
Instead of the rose benzal, phloxine and eosine yel-lowish used in -the examples described before, other fluo-rescein-based dyes, such as eosine bluish (CZOH6Hr2C1NaZO9;
color index: acid red 91) and erythrasine (CZ~HZ9Nz0~Sz%
color index: acid red 52) may also be used. The detection _, ~132~13 paper prepared with such other fluorescein-based dyes proved to be capable of detecting basic gases with practi-cal accuracy, though the detection sensitivity is somewhat more susceptible to variations.
In the examples described before, pare-toluenesulfonic acid is used as the hydrogen ion concentration adjuster.
Other strong organic acids, such as naphthalenesulfonic acid and benzensulfonic acid, also proved to be much more beneficial than hydrochloric acid in the lengthening of the shelf life of the detention paper.
Furthermore, glycerin, which is used as the humectant, may also be replaced with other substances that do not change the hydrogen ion concentration, such as ethylene glycol and polyalcohol. The paper prepared with such humectants also produce similar effects.
Claims (4)
1. Basic-gas detection paper prepared by impregnating a sheet of paper with a fluorescein-based dye, a strong organic acid and a humectant.
2. Basic-gas detection paper according to claim 1, in which the fluorescein-based dye is selected from a group consisting of rose benzal, phloxine, erythrosine, eosine yellowish and eosine bluish.
3. Basic-gas detection paper according to claim 1 or 2, in which the strong organic acid is selected from a group consisting of para-toluenesulfonic acid, naphthalenesulfonic acid and benzensulfonic acid.
4. Basic-gas detection paper according to any one of claims 1 to 3, in which the humectant is polyhydric alcohol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27893893A JP3173694B2 (en) | 1993-09-13 | 1993-09-13 | Basic gas detection tape |
| JP278938/1993 | 1993-09-13 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2132413A1 CA2132413A1 (en) | 1995-03-14 |
| CA2132413C true CA2132413C (en) | 2004-11-16 |
Family
ID=17604164
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2132413 Expired - Lifetime CA2132413C (en) | 1993-09-13 | 1994-09-13 | Basic-gas detection paper |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP3173694B2 (en) |
| CA (1) | CA2132413C (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000003242A2 (en) * | 1998-07-11 | 2000-01-20 | Bickar David A | Solid solventless protein assay with standards |
| US6217827B1 (en) | 1999-03-25 | 2001-04-17 | Zellweger Analytics, Inc. | Hydride gas detecting tape |
| KR100710561B1 (en) * | 2000-07-12 | 2007-04-24 | 에스케이 주식회사 | Silent mark for oil product and detection method thereto |
| KR20010093340A (en) * | 2001-03-30 | 2001-10-29 | 전영관 | The method of detection for dangerous gas leakage |
| CN101907560A (en) * | 2010-07-27 | 2010-12-08 | 浙江大学 | Ammonia gas sensor and detection method based on nanoporous reflective sensing material |
| KR102394893B1 (en) * | 2020-06-08 | 2022-05-09 | 전주대학교 산학협력단 | Colorimetric analysis reagent, method for manufacturing colorimetric analysis reagent and method for manufacturing colorimetric analysis tape |
-
1993
- 1993-09-13 JP JP27893893A patent/JP3173694B2/en not_active Expired - Fee Related
-
1994
- 1994-09-13 CA CA 2132413 patent/CA2132413C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP3173694B2 (en) | 2001-06-04 |
| JPH0783911A (en) | 1995-03-31 |
| CA2132413A1 (en) | 1995-03-14 |
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