WO2020130789A1 - An optical chemical sensor for measuring dissolved ammonia concentration - Google Patents
An optical chemical sensor for measuring dissolved ammonia concentration Download PDFInfo
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- WO2020130789A1 WO2020130789A1 PCT/MY2019/050111 MY2019050111W WO2020130789A1 WO 2020130789 A1 WO2020130789 A1 WO 2020130789A1 MY 2019050111 W MY2019050111 W MY 2019050111W WO 2020130789 A1 WO2020130789 A1 WO 2020130789A1
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- membrane
- fluorophore
- emeraldine salt
- chemical sensor
- optical
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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
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
- G01N21/643—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" non-biological material
-
- 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
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
- G01N2021/6432—Quenching
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—Specially adapted to detect a particular component
- G01N33/0054—Specially adapted to detect a particular component for ammonia
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Definitions
- the present invention relates to a sensor for measuring ammonia concentration. More particularly, the present invention relates to an optical chemical sensor for measuring dissolved ammonia concentration.
- an optical chemical sensor for measuring dissolved ammonia (70) concentration is provided.
- the optical chemical sensor is comprised of a chemical sensing membrane (100).
- the chemical sensing membrane (100) includes a fluorophore (40), an emeraldine salt and a membrane matrix (10) disposed on a polyester substrate (20), wherein the fluorophore (40) and the emeraldine salt are immobilized in the membrane matrix (10).
- the fluorophore (40) is a transition metal pyridynal complex.
- the membrane matrix (10) is a photo-transmissive polymer.
- FIG. 3 shows a graph of FRET responses of an optical chemical sensor towards dissolved ammonia concentrations and a linear Stern-Volmer plot of dissolved ammonia concentrations.
- the light absorption of the emeraldine base (50) lowers the fluorescence emission by the fluorophore (40).
Abstract
The present invention relates to an optical chemical sensor for measuring dissolved ammonia (70) concentration in a sample. The optical chemical sensor measures dissolved ammonia (70) concentration based on a Forster Resonance Energy Transfer or FRET effect. The optical chemical sensor comprises a chemical sensing membrane (100) attached to an optical waveguide with a photo-detector. The chemical sensing membrane (100) includes a fluorophore (40), an emeraldine salt and a membrane matrix (10), wherein the fluorophore (40) and the emeraldine salt are immobilized in the membrane matrix (10). The membrane matrix (10) immobilized with the fluorophore (40) and the emeraldine salt is disposed on a polyester substrate (20).
Description
AN OPTICAL CHEMICAL SENSOR FOR MEASURING DISSOLVED AMMONIA
CONCENTRATION
FIELD OF INVENTION
The present invention relates to a sensor for measuring ammonia concentration. More particularly, the present invention relates to an optical chemical sensor for measuring dissolved ammonia concentration.
BACKGROUND OF THE INVENTION
Measurement of ammonia in an aquatic environment especially aquaculture is crucial as ammonia, even when present in a small amount can negatively affects the marine organism’s health and behaviour. According to Randall and Ip et.al. (2006), high ammonia concentration causes damage to the gill and kidney of the marine organism, meanwhile neurotoxicity, hyperventilation and convulsion have also been observed. Furthermore, ammonia when present in its unionized form as NH3 is considered toxic and may cause fatality to the marine organism if its concentration exceeds certain threshold value. Moreover, this would ultimately affects the quality and production of marine products by the aquaculture industry. Therefore, numerous analytical methods have been developed to measure ammonia in an aquatic environment.
The most commonly used analytical method to measure ammonia in solution is based on Berthelot reaction as described in United States Patent No 5,620,900. The method measures ammonia by measuring the optical intensity of indophenol blue formed from the reaction between ammonia with phenol derivative in alkaline solution. However, the method consumes significant amount of reagents, thereby it is unsuitable to be applied for continuous monitoring of ammonia in an aquatic environment. Despite the analytical method based on Berthelot reaction has evolved into an integrated microfluidic system for it to be applied in continuous monitoring of ammonia, it still requires significant amount of reagents which eventually leads to significant amount of waste generation (Sraj et al. 2004).
In addition to the Berthelot reaction, analytical methods based on optical intensity measurement have been developed to measure ammonia such as a
fluorescence sensor described by Waich et al. (2008). Nevertheless, these methods suffer from optical path displacement and photo bleaching of the optical probe.
Other than that, an analytical method based on electrochemistry has also been developed. For example, an electrochemical detection of ammonia that involves the use of a working electrode comprising glassy carbon or boron doped diamond, a counter electrode and an electrolyte is disclosed in a PCT Publication No WO 2007/020410 A1 . Such method is susceptible to interference from the salinity of water sample and the used electrodes may be eventually subjected to marine corrosion.
Accordingly, there is a need for a sensor to measure ammonia concentration that addresses the above mentioned drawbacks.
SUMMARY OF INVENTION
In a first aspect of the present invention, an optical chemical sensor for measuring dissolved ammonia (70) concentration is provided. The optical chemical sensor is comprised of a chemical sensing membrane (100). The chemical sensing membrane (100) includes a fluorophore (40), an emeraldine salt and a membrane matrix (10) disposed on a polyester substrate (20), wherein the fluorophore (40) and the emeraldine salt are immobilized in the membrane matrix (10).
Preferably, the fluorophore (40) is a transition metal pyridynal complex.
Preferably, the fluorophore (40) is a ruthenium bipyrydinal complex.
Preferably, the membrane matrix (10) is a photo-transmissive polymer.
Preferably, the membrane matrix (10) is a polyether polyurethane hydrogel.
Preferably, the chemical sensing membrane (100) further includes a fluoropolymer layer (30) coated on the membrane matrix (10).
Preferably, the thickness of the fluoropolymer layer is approximately 12 pm to
50 miTΊ.
In a second aspect of the present invention, a method for fabricating a chemical sensing membrane (100) of an optical chemical sensor is provided. The method is characterised by the steps of synthesizing an emeraldine salt; spin-coating the emeraldine salt on a glass substrate; mixing the emeraldine salt with an amount of fluorophore (40) to produce a mixture of emeraldine salt and fluorophore; dissolving and blending the mixture of emeraldine salt and fluorophore with a photo-transmissive polymer solution in a non-polar organic solvent to obtain a membrane cocktail; dropcasting the membrane cocktail on a polyester substrate (20); and drying the membrane cocktail until a transparent membrane is formed.
Preferably, the amount of fluorophore (40) is in an approximation range of 0.4 mg to 1 mg.
Preferably, the amount of photo-transmissive polymer solution is in an approximation range of 20 mg to 50 mg.
Preferably, the volume of non-polar organic solvent is in an approximation range of 2 ml to 5 ml.
Preferably, the step of synthesizing an emeraldine salt includes reacting dodecylbenzene sulfonic acid, ammonium persulfate and distilled aniline until a dark green solution is obtained; and dialysing the dark green solution against a sodium dodecyl sulphate solution to obtain the emeraldine salt.
Preferably, the method includes coating the transparent membrane with a fluoropolymer layer (30).
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
FIG. 1 illustrates a chemical sensing membrane (100) of an optical chemical sensor according to an embodiment of the present invention.
FIG. 2 illustrates a reaction diagram of an optical chemical sensor according to an embodiment of the present invention.
FIG. 3 shows a graph of FRET responses of an optical chemical sensor towards dissolved ammonia concentrations and a linear Stern-Volmer plot of dissolved ammonia concentrations.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the present invention will be described herein below with reference to the accompanying drawings. In the following description, well known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.
The present invention relates to an optical chemical sensor for measuring dissolved ammonia concentration in a sample. The sample can be in a liquid form or a gaseous form, wherein the gaseous form is dissolved in water prior to measurement. The optical chemical sensor is based on an emeraldine salt, wherein a change in its optochromic property is used in quantifying the dissolved ammonia concentration in the sample. In particular, the optical chemical sensor measures dissolved ammonia concentration based on a Forster Resonance Energy Transfer or FRET effect and thus, the measurement is not affected by water salinity. The optical chemical sensor can be adapted and used in a flow injection analysis so as to allow continuous monitoring of dissolved ammonia concentration.
The optical chemical sensor comprises a chemical sensing membrane (100) attached to an optical waveguide with a photo-detector. Referring to FIG. 1 , the chemical sensing membrane (100) includes a fluorophore, an emeraldine salt and a membrane matrix (10), wherein the fluorophore and the emeraldine salt are immobilized in the membrane matrix (10). The membrane matrix (10) immobilized with the fluorophore and the emeraldine salt is disposed on a polyester substrate (20).
The fluorophore functions as a donor in the Forster resonance energy transfer effect, wherein the fluorophore in its excited state transfers its excitation energy to an acceptor and thereby, causing the acceptor to emit its fluorescence characteristic once the acceptor interacts with the dissolved ammonia. Preferably, the fluorophore is a
transition metal pyridynal complex, wherein the fluorophore is suitably a ruthenium bipyrydinal complex.
The emeraldine salt functions as an acceptor in the Forster resonance energy transfer effect, wherein the emeraldine salt accepts excitation energy from the excited fluorophore to emit its fluorescence characteristic at lower energy state in the presence of the dissolved ammonia.
The membrane matrix (10) functions as an immobilization support to the fluorophore and the emeraldine salt. The membrane matrix (10) is a phototransmissive polymer such as polyether polyurethane, polyvinyl chloride, polymethylmethacrylate or polysiloxane. Preferably, the membrane matrix (10) is a polyether polyurethane hydrogel as the polyether polyurethane has adventitious properties of being highly permeable of ammonia dissolved in an aqueous medium and also the polyether polyurethane relatively does not react with the fluorophore or the emeraldine salt immobilized in the membrane matrix (10).
Preferably, the chemical sensing membrane (100) further includes a fluoropolymer layer (30) coated on the membrane matrix (10). The fluoropolymer layer (30) is suitably made of tetrafluropolymer, or any proton exchanger agent such as Nafion cast. The incorporation of the fluoropolymer layer (30) as an interfacial layer is to block any interference species especially cations such as hydronium ions from reacting with the emeraldine salt immobilized in the membrane matrix (10). Moreover, the fluoropolymer layer (30) prevents the emeraldine salt from leaching out of the membrane matrix (10).
A method for fabricating the chemical sensing membrane (100) is described herein below. The method is initiated by synthesizing emeraldine salt, wherein the synthesis of the emeraldine salt is performed by reacting dodecylbenzene sulfonic acid, ammonium persulfate and distilled aniline until a dark green solution is obtained; and dialysing the dark green solution against a sodium dodecyl sulphate solution to obtain the emeraldine salt. Preferably, the concentration of dodecylbenzene sulfonic acid is 0.25 M, the weight of ammonium persulfate is 0.36 g, the volume of distilled aniline is 0.6 ml and the concentration of the sodium dodecyl sulphate solution is 0.05 M.
Thereon, the emeraldine salt is spin coated on a glass substrate and mixed with an amount of fluorophore to produce a mixture of emeraldine salt and fluorophore. Preferably, the amount of fluorophore is in an approximation range of 0.4 mg to 1 mg. Preferably, the fluorophore is a transition metal pyridynal complex.
The mixture of emeraldine salt and fluorophore is then dissolved and blended with a photo-transmissive polymer solution in a non-polar organic solvent resulting in a membrane cocktail. Such photo-transmissive polymer includes, but not limited to, polyether polyurethane, polyvinyl chloride, polymethylmethacrylate, and polysiloxane. Preferably, the amount of photo-transmissive polymer solution is in an approximation range of 20 mg to 50 mg. Such non-polar organic solvent includes, but not limited to, tetrahydrofuran, hexane or dodecane. Preferably, the volume of non-polar organic solvent is in an approximation range of 2 ml to 5 ml.
Next, the membrane cocktail is drop casted on a polyester substrate (20) to form a uniform homogenous membrane cocktail. Preferably, the polyester substrate (20) is biaxially-oriented polyethylene terephthalate.
The membrane cocktail is then dried at room temperature until a transparent membrane is formed, wherein the transparent membrane formed is the membrane matrix (10) immobilized with the fluorophore and the emeraldine salt. The membrane cocktail is suitably dried for approximately 30 mins.
The transparent membrane is coated with a fluoropolymer layer (30), wherein the fluoropolymer layer (30) is preferably made of tetrafluropolymer, or any proton exchanger agent such as Nafion cast. The thickness of the fluoropolymer layer coated on the membrane should allow the analyte of interest which is dissolved ammonia to pass through the layer to react with the emeraldine salt immobilized in the membrane matrix (10). Preferably, the thickness of the fluoropolymer layer is approximately 12 pm to 50 pm.
In order to assemble the optical chemical sensor, the chemical sensing membrane (100) is attached or clamped to an optical fibre light guide or any optical waveguide with a photo-detector having a suitable wavelength between 600 nm to 650 nm.
A method for measuring dissolved ammonia concentration in a sample using the optical chemical sensor is described with reference to FIG. 2. The sample can be in a liquid form or a gaseous form, wherein the gaseous form is dissolved in water prior to measurement. Initially, a light source (60) propagates through the optical waveguide while the chemical sensing membrane (100) is immersed in the sample. Preferably, the propagated light source (60) is within a wavelength range of 540 nm to 660 nm. The propagation of light to the chemical sensing membrane (100) induces excitation energy of the fluorophore (40). Consequently, the fluorophore (40) transfers non- radiative energy to the emeraldine salt causing the emeraldine salt to be protonated. The protonated emeraldine salt reacts with the dissolved ammonia (70) diffused in the membrane matrix (10) from the sample resulting in the emeraldine salt to be deprotonated into an emeraldine base (50) while the dissolved ammonia (70) is oxidized into ammonium ion as provided by the equation below:
PAH+ + NH3 ® PA + NH
The higher the concentration of dissolved ammonia (70) that diffuses into the chemical sensing membrane (100), the more energy is transferred from the fluorophore (40) to the emeraldine salt resulting in the production of the emeraldine base (50) that absorbs light spectrum within the wavelength range of 540 nm to 660 nm. The light absorption of the emeraldine base (50) lowers the fluorescence emission by the fluorophore (40).
Thereon, the fluorescence emission by the chemical sensing membrane (100) is measured by the photo-detector. Preferably, the fluorescence emission is filtered prior to the measurement of the photo-detector to ensure only a certain wavelength of the fluorescence emission is being measured.
The measurement of the fluorescence emission is used to determine dissolved ammonia (70) concentration in the sample. In particular, the dissolved ammonia (70) concentration is determined by converting the phase degree of the measured fluorescence emission to dissolved ammonia (70) concentration based on a Stern- Volmer plot, wherein the Stern-Volmer plot depicts the relationship between the fluorophore (40) lifetime and the dissolved ammonia (70) concentration. The Stern- Volmer plot is derived based on the equation provided below:
- 1 + kqT0[Q], wherein T0 is referred to the fluorophore (40) lifetime in the absence of a quencher or emeraldine base (50), kq is referred to the constant rate of quenching, Q is referred to the quencher concentration or the dissolved ammonia (70) concentration and T is referred to the fluorophore (40) lifetime in the presence of the quencher or emeraldine base (50) in which the fluorophore (40) lifetime is determined from the phase degree of the measured fluorescence emission. The optical chemical sensor can be regenerated by immersing the chemical sensing membrane (100) in a concentration of acid solution causing the emeraldine base (50) to revert to emeraldine salt. Preferably, the concentration of acid solution is approximately in a range of 0.01 M to 0.0001 M. Such acid solution includes, but not limited to nitric acid, hydrochloric acid and acetic acid.
Although the optical chemical sensor is used to measure dissolved ammonia (70) concentration, it may be apparent that the optical chemical sensor can also be used to measure ammonium and hydroxide ions. This is due to dissolved ammonia (70) dissociates into ammonium and hydroxide ions upon reacting with the emeraldine salt. Hence, the measurement of dissolved ammonia (70) concentration correlates to the measurement of ammonium and hydroxide ions present in the sample.
Herein, the present invention is further illustrated by the following examples. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practised and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiment herein.
Examples are illustrated as follows:
1.0 Synthesis of a mixture of emeraldine salt and fluorophore
An emeraldine salt was synthesized by reacting 0.25 M dodecylbenzene sulfonic acid, 0.36 g ammonium persulfate and 0.6 ml distilled aniline until a dark green solution is obtained; and dialysing the dark green solution against 0.05 M sodium dodecyl sulphate solution to obtain the emeraldine salt. The emeraldine salt was then
spin coated on a glass substrate and mixed with 0.4 mg ruthenium bypirydinal complex to produce a mixture of emeraldine salt and fluorophore.
2.0 Fabrication of chemical sensing membrane and optical chemical sensor
The mixture of emeraldine salt and fluorophore was dissolved and blended with polyether polyurethane in tetrahydrofuran to obtain a membrane cocktail. The membrane cocktail was then drop casted on a biaxially-oriented polyethylene terephthalate. The membrane cocktail was dried at room temperature for approximately 30 mins to form a transparent membrane. The optical density of the transparent membrane was investigated to ensure that the excitation of emeraldine base is within the range of 540 nm to 660 nm which is overlapping with emission region of the ruthenium bypirydinal complex.
The transparent membrane was then coated with a tetrafluropolymer layer. The tetrafluoropolymer layer serves to block interference species such as cations that might react with the emeraldine salt immobilized in the membrane matrix. The tetrafluoropolymer layer also serves to prevent the leaching of emeraldine salt out of the membrane matrix. The thickness of the fluoropolymer layer coated on the membrane is suitably 50 pm, so as to allow maximum diffusion of analyte of interest through the fluoropolymer layer to react with the emeraldine salt immobilized in the membrane matrix.
As the chemical sensing membrane had been prepared, the chemical sensing membrane was attached or clamped at the end of optical fiber light guide or any optical waveguide with a photo-detector having a suitable wavelength between 600 nm to 650 nm. This setup is referred as an optical chemical sensor, wherein the optical chemical sensor was used to measure an analyte of interest in particular, dissolved ammonia concentration.
3.0 Sensitivity and linear working range of the optical chemical sensor
The optical chemical sensor was tested for its sensitivity and a linear working range in measuring dissolved ammonia concentration. The sensitivity and the linear working range of the optical chemical sensor were tested by immersing the chemical sensing membrane in varying dissolved ammonia concentrations ranging from 10 ppb to 250 ppb, wherein a sample without dissolved ammonia serves as a blank. The phase
degree of the measured fluorescence emission as recorded by a photo-detector changed accordingly to the dissolved ammonia concentrations within an approximately 2 mins response time. Based on FRET responses of the optical chemical sensor towards varying dissolved ammonia concentrations, a linear Stern-Volmer plot of dissolved ammonia concentrations was obtained ranging from 0 to 250 ppb. A graph of FRET responses of an optical chemical sensor towards dissolved ammonia concentrations and a linear Stern-Volmer plot of dissolved ammonia concentrations is as shown in FIG. 3.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specifications are words of description rather than limitation and various changes may be made without departing from the scope of the invention.
REFERENCES
[1 ] Randall, D.J. and Ip, Y.K., 2006. Ammonia as a respiratory gas in water and air-breathing fishes. Respiratory physiology & neurobioiogy, 754(1 -2), pp.216- 225.
[2] Sraj, L.O.C., Almeida, M.I.G., Swearer, S.E., Kolev, S.D. and McKelvie, I.D., 2014. Analytical challenges and advantages of using flow-based methodologies for ammonia determination in estuarine and marine waters. TrAC Trends in Analytical Chemistry, 59, pp.83-92.
[3] Waich, K., Mayr, T. and Klimant, I., 2008. Fluorescence sensors for trace monitoring of dissolved ammonia. Talanta, 77(1), pp.66-72.
Claims
1 . An optical chemical sensor comprising:
a) a chemical sensing membrane (100), wherein the chemical sensing membrane (100) includes a fluorophore (40),
characterised in that the chemical sensing membrane (100) further includes: b) an emeraldine salt; and
c) a membrane matrix (10) disposed on a polyester substrate (20), wherein the membrane matrix (10) is immobilized with the fluorophore (40) and the emeraldine salt.
2. The optical chemical sensor as claimed in claim 1 , wherein the fluorophore (40) is a transition metal pyridynal complex.
3. The optical chemical sensor as claimed in claim 1 , wherein the fluorophore (40) is a ruthenium bipyrydinal complex.
4. The optical chemical sensor as claimed in claim 1 , wherein the membrane matrix (10) is a photo-transmissive polymer.
5. The optical chemical sensor as claimed in claim 1 , wherein the membrane matrix (10) is a polyether polyurethane hydrogel.
6. The optical chemical sensor as claimed in claim 1 , wherein the chemical sensing membrane (100) further includes a fluoropolymer layer (30) coated on the membrane matrix (10).
7. The optical chemical sensor as claimed in claim 6, wherein the thickness of the fluoropolymer layer (30) is approximately 12 pm to 50 pm.
8. A method for fabricating a chemical sensing membrane (100) of an optical chemical sensor is characterised by the steps of:
a) synthesizing an emeraldine salt;
b) spin-coating the emeraldine salt on a glass substrate;
c) mixing the emeraldine salt with an amount of fluorophore (40) to produce a mixture of emeraldine salt and fluorophore;
d) dissolving and blending the mixture of emeraldine salt and fluorophore with a photo-transmissive polymer solution in a non-polar organic solvent to obtain a membrane cocktail;
e) drop-casting the membrane cocktail on a polyester substrate (20); and f) drying the membrane cocktail until a transparent membrane is formed.
9. The method as claimed in claim 8, wherein the amount of fluorophore (40) is in an approximation range of 0.4 mg to 1 mg.
10. The method as claimed in claim 8, wherein the amount of photo-transmissive polymer solution is in an approximation range of 20 mg to 50 mg.
1 1 . The method as claimed in claim 8, wherein the volume of non-polar organic solvent is in an approximation range of 2 ml to 5 ml.
12. The method as claimed in claim 8, wherein the step of synthesizing the emeraldine salt includes:
a) reacting dodecylbenzene sulfonic acid, ammonium persulfate and distilled aniline until a dark green solution is obtained; and b) dialysing the dark green solution against a sodium dodecyl sulphate solution to obtain the emeraldine salt.
13. The method as claimed in claim 8, wherein the method further includes coating the transparent membrane with a fluoropolymer layer (30).
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| MYPI2018002760 | 2018-12-17 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6046055A (en) * | 1996-10-16 | 2000-04-04 | Avl Medical Instruments Ag | Luminescence-optical method and sensor layer for quantitative determination of at least one chemical component of a gaseous or liquid sample |
| US6610367B2 (en) * | 1998-11-16 | 2003-08-26 | California Institute Of Technology | Use of an array of polymeric sensors of varying thickness for detecting analytes in fluids |
| US7592184B2 (en) * | 1999-11-09 | 2009-09-22 | Photonic Biosystems, Inc. | Ammonia detection and measurement device |
| WO2010091334A2 (en) * | 2009-02-09 | 2010-08-12 | Edwards Lifesciences Corporation | Analyte sensor and fabrication methods |
| DE102015122463A1 (en) * | 2015-12-21 | 2017-06-22 | Endress+Hauser Conducta Gmbh+Co. Kg | Membrane and method of making a membrane |
-
2019
- 2019-12-16 WO PCT/MY2019/050111 patent/WO2020130789A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6046055A (en) * | 1996-10-16 | 2000-04-04 | Avl Medical Instruments Ag | Luminescence-optical method and sensor layer for quantitative determination of at least one chemical component of a gaseous or liquid sample |
| US6610367B2 (en) * | 1998-11-16 | 2003-08-26 | California Institute Of Technology | Use of an array of polymeric sensors of varying thickness for detecting analytes in fluids |
| US7592184B2 (en) * | 1999-11-09 | 2009-09-22 | Photonic Biosystems, Inc. | Ammonia detection and measurement device |
| WO2010091334A2 (en) * | 2009-02-09 | 2010-08-12 | Edwards Lifesciences Corporation | Analyte sensor and fabrication methods |
| DE102015122463A1 (en) * | 2015-12-21 | 2017-06-22 | Endress+Hauser Conducta Gmbh+Co. Kg | Membrane and method of making a membrane |
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