CA2072522C - Colorimetric testing and measuring device for gases - Google Patents
Colorimetric testing and measuring device for gasesInfo
- Publication number
- CA2072522C CA2072522C CA 2072522 CA2072522A CA2072522C CA 2072522 C CA2072522 C CA 2072522C CA 2072522 CA2072522 CA 2072522 CA 2072522 A CA2072522 A CA 2072522A CA 2072522 C CA2072522 C CA 2072522C
- Authority
- CA
- Canada
- Prior art keywords
- carrier
- indicator
- moisture
- gases
- diethylphthalate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators
- G01N31/223—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators
- G01N31/223—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols
- G01N31/224—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols for investigating presence of dangerous gases
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Biochemistry (AREA)
- Biophysics (AREA)
- Molecular Biology (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Dispersion Chemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Toxicology (AREA)
- 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
An improved measuring apparatus for the colorimetric indication of gases is disclosed. The apparatus comprises a carrier that is impregnated with a solution of a moisture retainer and a detection indicator. A mixture of sulfolane and diethylphthalate is used as the moisture retainer. To measure hydride gases, such as arsine or phosphine, the indicator con-sists of palladium tetramine chloride. The impregnating solution may be applied to a paper carrier or to a granular silica gel carrier. Due to the presence of the moisture retainer, the moisture required for the indicating reaction remains on the indicator carrier for a longer period of time, both during stor-age of the device and during measurements, when the carrier is exposed to the gaseous substance that is to be indicated.
Description
The present invention relates to a testing and measur-ing device for the colorimetric detection of gaseous substances.
The device has a carrier for a detection indicator which indicator, together with an additive that serves as a moisture retainer, impregnates the carrier.
A similar testing and measuring device is already known from DE-A-40 20 753.
The known measuring device is used for the reliable detection of, for example, hydride gases, such as arsine or phos-phine, which are highly toxic components generated during pro-cessing, for example, in the semiconductor industry. An indicating apparatus that is both reliable and easy to use is required for the detection of such gases. For many indicator materials, such as, for example, the palladium salt that is used in known dosimeters to detect hydride gases, it is essential that the indicator has a specific degree of moisture available to it, both during storage in the unused state and also during more protracted measuring periods. This is necessary in order that during a period of storage the indicator does not dry out and that during the measurement process there is sufficient moisture available for the colour reaction. Glycols, in particular ethylene glycol, are used as readily available moisture retainers. However, since to an increasing degree ever longer measuring periods are required for continuous monitoring of air, glycols have proved to be less than adequate as a moisture retainer. Long-term measure-ments typically require a period of eight, twelve, or even twenty--1- ~
four hours. Thus, there is a need for a moisture retainer for the impregnating solution of colorimetric testing and measuring apparatuses that can satisfy the requirement of the protracted measurement periods.
Thus, it is an object of the present invention to improve a testing and measuring device of the kind described above in such a manner that the moisture required for the detection reaction remains on the indicator carrier for a longer period of time, both during storage, when the device is not used, and also during measurement, when it is acted upon by the gaseous substance that is to be detected.
This object may be achieved by using a mixture of sulfolane and diethylphthalate as the moisture retainer.
Thus, according to one aspect, the invention provides a testing and measuring device for colorimetrically detecting gaseous substances, the device comprising:-a carrier on which gaseous substances are detected, said carrier being impregnated with a detecting indicator and a moisture store, said moisture store being a mixture of sulfolane and diethylphthalate.
The advantage of the present invention lies essentially in the fact that a much longer retention time of the moisture required for indication purposes is achieved. It means that the drying of the indicator is prevented during a longer continuous measurement time, even if the indicator is exposed to a relatively dry gas. A moisture retainer of this kind is useful not only for indicators that are used to detect hydride gases, but can be generally used where the detection indicator must have a specific -2a-` :
_ 26541-91 2~J72522 degree of moisture in order to provide a colour reaction with the gaseous substance that is to be indicated.
Sulfolane is a common name that is given to tetra-hydrothiophene-l,l-dioxide. Diethylphthalate is another name used to designate the substance known as phthalic acid diethylester.
A particularly suitable mixture ratio between sulfo-lane and diethylphthalate is 10 parts of sulfolane to one part of diethylphthalate. A mixture of this kind has a melting point of 0C, which means that it can be used in a temperature range from 2C to 40C with detection indicators comprising an impregnating solution. Because of the lower vapour pressure resulting from the lower melting point, a detection indicator with an impregnating solution of this kind does not dry out even in the case of con-tinuous measurements lasting longer than eight hours.
In order to measure hydride gases, it is useful to combine the moisture retainer with a palladium (II) chloride as an indicator, so as to form an impregnating solution. This impregnat-ing solution has the advantage that it remains colourless during the mentioned longer periods of time and assumes a clearly visible coloration when acted upon by hydride gases.
Palladium tetramine chloride is also suitable as an indicator for measuring hydride gases. Both impregnating solutions for indicating hydride gases have good storage characteristics thanks to the long-term retention effect of the sulfolane-diethylphthalate mixture, and both display outstanding indication sensitivity since the indicator, colourless in the original state, ~ 26541-91 assumes a clearly visible coloration in the presence of a hydride gas.
An impregnating solution that is suitable, for example, for indicating phosphine is produced as follows. 5 g of pulverized palladium (II) chloride are weighed into a measuring flask and dissolved in 50 ml of ammonia at approximately 100C.
Once the excess ammonia has been driven off, and the solution has cooled to room temperature, 100 ml of water and 100 ml of methanol are added to it. After this, approximately 250 g of a sulfolane-diethylphthalate mixture are weighed out and, when required, made up with methanol. The impregnating solution produced in this manner is impregnated onto the indicator carrier. This carrier can be a paper disk or a porous, granular silica gel carrier. The impregnated paper disk is, for example, clamped into a housing and used as a dosimeter by exposing the surface of the disk to the gas that is to be detected and the resulting coloration is used as a scale for the quantity of substance that is to be indicated.
The granular silica gel carrier is, for example, filled into a test tube and serves for the colorimetric determination of the concen-tration of gaseous toxic substances.
The above example describes as a finished detection indicator a mixture in solution of palladium tetramine chloride, sulfolane and diethylphthalate, the palladium tetramine chloride being extracted from palladium (II) chloride to which ammonia has been added. If, in contrast thereto, palladium (II) chloride is to serve as a colour indicator, preparation is carried out in the same way, although without adding ammonia to the palladium (II) chloride.
The invention will be further illustrated by way of a preferred embodiment and with reference to the accompanying drawings in which:
Figure 1 shows, in cross-section, a dosimeter for testing gases according to one preferred embodiment of the invention.
Figure 1 shows a dosimeter which is used as a testing device for gases and which is formed from a test disk with a disk carrier (1) that is of circular cross section, on which is laid a plate-shaped impregnated indicator paper (2) which is then held on the disk carrier (1) by means of a clamp ring (3). The annular clamp ring (3) leaves a disk opening (4) unobstructed and the gas that is to be indicated has access to the indicator paper through this space. There, the gas reacts with the indicator solution that impregnates the paper to bring about a change in colour. The intensity of the colour, compared with a colour standard, is used as a measure for the quantity of gas that is to be indicated and which has been collected during the exposure time. A solution of palladium tetramine chloride with a sulfolane-phthalic acid diethyl-ester mixture at a ratio of 10:1 serves as the impregnating agent.
The device has a carrier for a detection indicator which indicator, together with an additive that serves as a moisture retainer, impregnates the carrier.
A similar testing and measuring device is already known from DE-A-40 20 753.
The known measuring device is used for the reliable detection of, for example, hydride gases, such as arsine or phos-phine, which are highly toxic components generated during pro-cessing, for example, in the semiconductor industry. An indicating apparatus that is both reliable and easy to use is required for the detection of such gases. For many indicator materials, such as, for example, the palladium salt that is used in known dosimeters to detect hydride gases, it is essential that the indicator has a specific degree of moisture available to it, both during storage in the unused state and also during more protracted measuring periods. This is necessary in order that during a period of storage the indicator does not dry out and that during the measurement process there is sufficient moisture available for the colour reaction. Glycols, in particular ethylene glycol, are used as readily available moisture retainers. However, since to an increasing degree ever longer measuring periods are required for continuous monitoring of air, glycols have proved to be less than adequate as a moisture retainer. Long-term measure-ments typically require a period of eight, twelve, or even twenty--1- ~
four hours. Thus, there is a need for a moisture retainer for the impregnating solution of colorimetric testing and measuring apparatuses that can satisfy the requirement of the protracted measurement periods.
Thus, it is an object of the present invention to improve a testing and measuring device of the kind described above in such a manner that the moisture required for the detection reaction remains on the indicator carrier for a longer period of time, both during storage, when the device is not used, and also during measurement, when it is acted upon by the gaseous substance that is to be detected.
This object may be achieved by using a mixture of sulfolane and diethylphthalate as the moisture retainer.
Thus, according to one aspect, the invention provides a testing and measuring device for colorimetrically detecting gaseous substances, the device comprising:-a carrier on which gaseous substances are detected, said carrier being impregnated with a detecting indicator and a moisture store, said moisture store being a mixture of sulfolane and diethylphthalate.
The advantage of the present invention lies essentially in the fact that a much longer retention time of the moisture required for indication purposes is achieved. It means that the drying of the indicator is prevented during a longer continuous measurement time, even if the indicator is exposed to a relatively dry gas. A moisture retainer of this kind is useful not only for indicators that are used to detect hydride gases, but can be generally used where the detection indicator must have a specific -2a-` :
_ 26541-91 2~J72522 degree of moisture in order to provide a colour reaction with the gaseous substance that is to be indicated.
Sulfolane is a common name that is given to tetra-hydrothiophene-l,l-dioxide. Diethylphthalate is another name used to designate the substance known as phthalic acid diethylester.
A particularly suitable mixture ratio between sulfo-lane and diethylphthalate is 10 parts of sulfolane to one part of diethylphthalate. A mixture of this kind has a melting point of 0C, which means that it can be used in a temperature range from 2C to 40C with detection indicators comprising an impregnating solution. Because of the lower vapour pressure resulting from the lower melting point, a detection indicator with an impregnating solution of this kind does not dry out even in the case of con-tinuous measurements lasting longer than eight hours.
In order to measure hydride gases, it is useful to combine the moisture retainer with a palladium (II) chloride as an indicator, so as to form an impregnating solution. This impregnat-ing solution has the advantage that it remains colourless during the mentioned longer periods of time and assumes a clearly visible coloration when acted upon by hydride gases.
Palladium tetramine chloride is also suitable as an indicator for measuring hydride gases. Both impregnating solutions for indicating hydride gases have good storage characteristics thanks to the long-term retention effect of the sulfolane-diethylphthalate mixture, and both display outstanding indication sensitivity since the indicator, colourless in the original state, ~ 26541-91 assumes a clearly visible coloration in the presence of a hydride gas.
An impregnating solution that is suitable, for example, for indicating phosphine is produced as follows. 5 g of pulverized palladium (II) chloride are weighed into a measuring flask and dissolved in 50 ml of ammonia at approximately 100C.
Once the excess ammonia has been driven off, and the solution has cooled to room temperature, 100 ml of water and 100 ml of methanol are added to it. After this, approximately 250 g of a sulfolane-diethylphthalate mixture are weighed out and, when required, made up with methanol. The impregnating solution produced in this manner is impregnated onto the indicator carrier. This carrier can be a paper disk or a porous, granular silica gel carrier. The impregnated paper disk is, for example, clamped into a housing and used as a dosimeter by exposing the surface of the disk to the gas that is to be detected and the resulting coloration is used as a scale for the quantity of substance that is to be indicated.
The granular silica gel carrier is, for example, filled into a test tube and serves for the colorimetric determination of the concen-tration of gaseous toxic substances.
The above example describes as a finished detection indicator a mixture in solution of palladium tetramine chloride, sulfolane and diethylphthalate, the palladium tetramine chloride being extracted from palladium (II) chloride to which ammonia has been added. If, in contrast thereto, palladium (II) chloride is to serve as a colour indicator, preparation is carried out in the same way, although without adding ammonia to the palladium (II) chloride.
The invention will be further illustrated by way of a preferred embodiment and with reference to the accompanying drawings in which:
Figure 1 shows, in cross-section, a dosimeter for testing gases according to one preferred embodiment of the invention.
Figure 1 shows a dosimeter which is used as a testing device for gases and which is formed from a test disk with a disk carrier (1) that is of circular cross section, on which is laid a plate-shaped impregnated indicator paper (2) which is then held on the disk carrier (1) by means of a clamp ring (3). The annular clamp ring (3) leaves a disk opening (4) unobstructed and the gas that is to be indicated has access to the indicator paper through this space. There, the gas reacts with the indicator solution that impregnates the paper to bring about a change in colour. The intensity of the colour, compared with a colour standard, is used as a measure for the quantity of gas that is to be indicated and which has been collected during the exposure time. A solution of palladium tetramine chloride with a sulfolane-phthalic acid diethyl-ester mixture at a ratio of 10:1 serves as the impregnating agent.
Claims (4)
1. A testing and measuring device for colorimetrically detecting gaseous substances, the device comprising:
a carrier on which gaseous substances are detected, said carrier being impregnated with a detecting indicator and a moisture store, said moisture store being a mixture of sulfolane and diethylphthalate.
a carrier on which gaseous substances are detected, said carrier being impregnated with a detecting indicator and a moisture store, said moisture store being a mixture of sulfolane and diethylphthalate.
2. The device of claim 1, wherein said mixture of sulfolane and diethylphthalate is 10:1 based on the percent by weight of the sulfolane to diethylphthalate.
3. The device of claim 1, wherein a substance to be detected is a hydride gas and said detecting indicator is a palladium (II) chloride.
4. The device of claim 1, wherein a substance to be detected is a hydride gas and said detecting indicator is a palladium tetramine chloride.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19914121633 DE4121633C2 (en) | 1991-06-29 | 1991-06-29 | Colorimetric test and measurement device for gases |
| DEP4121633.4 | 1991-06-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2072522A1 CA2072522A1 (en) | 1992-12-30 |
| CA2072522C true CA2072522C (en) | 1995-08-01 |
Family
ID=6435100
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2072522 Expired - Fee Related CA2072522C (en) | 1991-06-29 | 1992-06-26 | Colorimetric testing and measuring device for gases |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0521300A2 (en) |
| CA (1) | CA2072522C (en) |
| DE (1) | DE4121633C2 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU833501A1 (en) * | 1979-07-24 | 1981-05-30 | Предприятие П/Я А-7815 | Indicator solution for making ammonia indicator tape |
| US4420567A (en) * | 1981-10-22 | 1983-12-13 | Mda Scientific, Inc. | Hydride gas detecting tape |
| JPS61296268A (en) * | 1985-06-25 | 1986-12-27 | Nippon Paionikusu Kk | Detection agent |
| DE4020753A1 (en) * | 1989-09-22 | 1991-04-04 | Draegerwerk Ag | COLORIMETRIC TEST AND MEASURING DEVICE FOR HYDRIDGAS |
-
1991
- 1991-06-29 DE DE19914121633 patent/DE4121633C2/en not_active Expired - Fee Related
-
1992
- 1992-05-29 EP EP92109020A patent/EP0521300A2/en not_active Ceased
- 1992-06-26 CA CA 2072522 patent/CA2072522C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2072522A1 (en) | 1992-12-30 |
| EP0521300A2 (en) | 1993-01-07 |
| DE4121633C2 (en) | 1998-09-17 |
| DE4121633A1 (en) | 1993-01-07 |
| EP0521300A3 (en) | 1994-03-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |