WO2012074368A1 - Phosphate sensor - Google Patents

Phosphate sensor Download PDF

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Publication number
WO2012074368A1
WO2012074368A1 PCT/MY2011/000155 MY2011000155W WO2012074368A1 WO 2012074368 A1 WO2012074368 A1 WO 2012074368A1 MY 2011000155 W MY2011000155 W MY 2011000155W WO 2012074368 A1 WO2012074368 A1 WO 2012074368A1
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Prior art keywords
phosphate
doped
depositing
layer
sensor
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PCT/MY2011/000155
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French (fr)
Inventor
Sajidah Binti Abd Aziz Aiman
Rais Bin Ahmad Mohd
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Mimos Berhad
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Publication of WO2012074368A1 publication Critical patent/WO2012074368A1/en

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G01N27/125Composition of the body, e.g. the composition of its sensitive layer
    • G01N27/126Composition of the body, e.g. the composition of its sensitive layer comprising organic polymers

Definitions

  • the present invention relates to an improved phosphate sensor for electrochemical sensing and method of preparing the same.
  • Phosphorus is a multivalent nonmetal element in the same with group nitrogen in the periodic table. It is found in nature in several allotropic forms, and is an essential element for the life of organism. Commonly, phosphorus can be found as phosphates, which consists of phosphorus atom bonded to four oxygen atoms. Phosphates are important substances in the human body. For example, calcium phosphate is a major structural component of teeth and bone. Phosphorus also is a part of DNA materials. The importance of phosphorus is not limited to human, it is also essential nutrient for early root development in plant. The phosphate levels in the organisms and environmental nowadays have been major concern over the years.
  • the excessive amount of phosphate in human can cause problem to health, such as kidney damage and osteoporosis. Therefore, leaching of inorganic phosphates in the river from agricultural and industrial activity has led to eutrophication.
  • the increasing of phosphate level could promote the growth of phosphate-dependent organisms such as algae on the water surface. These organisms use great amounts of oxygen in water and prevent the sunlight entering the water which will disrupt normal functioning of the ecosystem.
  • silver-silver chloride (Ag/AgCl) electrode has been employed as the electrochemical transducer in chemical sensors and reference electrode. While the Ag/AgCl electrode works best in the bulky glass electrode equipped with
  • the miniaturized solid state version employs hydrophilic polymeric membrane as an internal layer.
  • the internal layer is hydrated with certain concentration of the target analyte, to act as the reference concentration.
  • concentration of the internal layer changes and thus causes the electrical signal to change. This requires frequent or daily calibration; else the sensor would transmit inaccurate data.
  • hydrophilic internal layer Another problem caused by the hydrophilic internal layer is its incompatibility with the sensing membranes.
  • the sensing membrane is usually highly lipophilic and its adhesion to hydrated hydrophilic internal layer is marginal and this results in peeling of the sensing membrane.
  • Conductive polymers have been introduced as electrochemical transducer and it has been shown that chemical sensors employing conductive polymer can produce fast response and stable signal without the use of additional internal layer.
  • Polypyrrole, polythiophene and polyaniline have been used as conductive polymers for chemical sensors.
  • Polypyrole has been the most widely used due to numerous advantages. Doping the polypyrrole increases the conductivity of the conducting polymer and this is usually achieved by electropolymerization from solution of pyrrole monomer containing electrolyte of chloride or nitrate salts of potassium. This causes a problem because the doping electrolyte is aqueous solution, whereas the pyrrole monomer is only moderately soluble in this electrolyte. Therefore, vigorous shaking and continuous stirring are required to achieve homogenous mixture and to maintain homogeneity of the doped polypyrrole on a phosphate sensor. Hence, there is still a need in the art for an improved phosphate sensor for electrochemical sensing.
  • a phosphate sensor comprising:
  • the polypyrole layer is homogeneously doped on the carbon layer.
  • the phosphate sensor is used in the manufacture of an ion selective electrode (ISE) and an ion sensitive field effect transistor (ISFET) phosphate sensing device.
  • ISE ion selective electrode
  • ISFET ion sensitive field effect transistor
  • a method of depositing doped polypyrrole electrochemical transducer layer comprising;
  • the provision of the method is advantageous as it results in producing a stable electrical signal and maintains homogeneity of the doped polypyrrole on a phosphate sensor.
  • FIG. 1 illustrates an electron transfer mechanism of phosphate ion inside the phosphate sensor with doped polypyrrole.
  • FIG.2 illustrates hydrophilic organic salts for polypyrrole doping.
  • FIG.3 illustrates a doped polypyrrole conducting polymer.
  • FIG.4 illustrates molecular structures of methyl methacrylate (2)
  • FIG.5 illustrates a cyclic voltammatograms of Ppy(Cl) from 50% v/v methanol solvent on Pt in 0.1M KC1 with 90, 150, 300 and 500 sec electropolymerisation time.
  • FIG.6 illustrates a potentiometric response of phosphate sensor with various electropolymerisation times.
  • the present invention relates to a miniaturized solid state phosphate sensor 10 as illustrated in FIG.l based on doped polypyrrole wherein the doping electrolytes are hydrophilic organic salts, as illustrated in FIG.2 dissolved in polar organic solvent, mixture of polar solvents or mixture of polar solvent and deionized water.
  • the miniaturized solid state phosphate sensor 10 based on doped polypyrrole electrochemical transducer that gives stable electrical signal.
  • the phosphate sensor 10 does not require the use of hydrophilic internal layer and is easy to fabricate.
  • FIG.l shows a phosphate sensor 10 comprising; a substrate 50, a thick film screen printed carbon layer 40, a phosphate sensing membrane 20; polypyrrole layer 30; wherein the polypyrrole layer 30 is homogeneously doped on the carbon layer 40.
  • FIG.l also shows that the polypyrrole conducting polymer 30 is deposited on top of screen printed thick film carbon 40 electrode. The carbon 40 surface must first be cleaned by sonication, and the pyrrole monomer is electropolymerized from the doping electrolyte.
  • the doped polypyrrole layer 30 having doping electrolyte of the following structure;
  • X CI, Br, I, BF 4 , PF 6 , OAc,CF 3 C0 2 ,N0 3 , Fe(CN) 6 , oxalate, tosylate
  • n 1 , 2, 3
  • R H, methyl, ethyl, butyl, allyl
  • the phosphate sensing membrane 20 is photo-cured co-polymer of methyl methacrylate and tetrahydrofurfuryl acrylate
  • SUBSTITUTE SHEET containing photoinitiator, diacrylate crosslinker, lipophilic ammonium salt and phosphate ionophore.
  • the phosphate sensing membrane 20 is bulk co-polymer of methyl methacrylate and tetrahydrofurfuryl acrylate containing photoinitiator, diacrylate crosslinker, lipophilic ammonium salt and phosphate ionophore.
  • the phosphate sensor 10 of the present invention is usable in the manufacture of an ion selective electrode (ISE) phosphate sensing device. Also, the phosphate sensor 10 is usable in the manufacture of an ion sensitive field effect transistor (ISFET) phosphate sensing device.
  • ISE ion selective electrode
  • ISFET ion sensitive field effect transistor
  • polypyrrole In the oxidized state polypyrrole exists as a polyradical cation, and at this state, anions such as chloride, are attracted electrostatically into the polymerized film as counter ions or dopants as illustrated in FIG.3.
  • the electrolytes of hydrophilic organic salts are prepared by dissolution in polar organic such as ethanol, methanol, 2-methoxy ethanol, dimethyl sulfoxide, acetonitrile or tetrahydrofuran.
  • polar organic such as ethanol, methanol, 2-methoxy ethanol, dimethyl sulfoxide, acetonitrile or tetrahydrofuran.
  • Mixture of polar organic solvents or mixture of the organic solvent and deionized water can also be used to dissolve the salts and the pyrrole monomer.
  • Pyrrole exhibits very high solubility in these solvents and vigorous shaking or stirring is not required for mixing or in keeping homogeneity during electropolymerization.
  • a method of depositing doped polypyrrole electrochemical transducer layer comprising;
  • step (a) the pyrrole monomer doped electrolyte solution having concentration ranges from 0.1M to 3M of pyrrole monomer and the hydrophilic dopant in a polar solvent having a concentration ranges from 0.1M to 3M.
  • the hydrophilic dopant is choline chloride.
  • the depositing step (c) is by electrochemical polymerization of constant current method with current density of 0.1 to 10 raA per square centimetre.
  • the depositing step (c) is by electrochemical polymerization utilising cyclic voltammetry method with scans between -IV and +1 V.
  • pyrrole electropolymerization process takes place at the screen printed carbon 40 working electrode while conventional double-junction reference electrode and platinum or glassy carbon electrode counter electrode complete the chronopotentiometry setup.
  • co-polymer of acrylates, methyl methacrylate (2) and tetrahydrofiirfuryl acrylate (3) has been employed as the phosphate sensing membranes 20 based on doped polypyrrole.
  • the monomers can be photo-polymerized from a cocktail containing the monomers, photoinitiator, crosslinker, lipophilic ammonium salt and phosphate ionophore.
  • bulk co-polymer of the above monomers can also be used as the sensing membrane 20.
  • the bulk co-polymer is first synthesized by refluxing the desired ratios of the monomers and benzoyl peroxide in benzene. After purification and drying, samples from the bulk polymer are dissolved with methylene chloride or tetrahydrofuran, along with the above components for phosphate sensing membrane 20. A few microliters of the bulk cocktail is dispensed
  • Polypyrrole is a conducting polymer due to its conjugated network of double bonds. In this manner it acts as a molecular wire and thus employed to conduct electrical current. Polypyrrole has another property that is of interest in chemical sensing - it undergoes reversible oxidation-reduction cycle at well-defined potentials. This property allows the use of polypyrrole as electrochemical transducer in chemical and biosensors.
  • the method of depositing doped polypyrrole electrochemical transducer layer increases the potential of obtaining homogeneously doped polypyrrole layer on the phosphate sensor.
  • the preparation of the phosphate sensor takes shorter time by utilizing the method of depositing doped polypyrrole electrochemical transducer layer.
  • the screen printed electrodes (SPE) with 4 mm diameter were cleaned ultrasonically with deionized water for 1 min.
  • the electrochemical polymerization was performed in a conventional three-electrode cell with a platinum as auxiliary electrode and the Ag/AgCl double junction as reference electrode using Autolab PGSTAT MODEL 128N for 90, 150, 300 and 500 seconds.
  • the polypyrrole (Ppy) films were generated with current density of 2 mA cm 2 in aqueous solution of 0.5M pyrrole
  • Phosphate cocktail were prepared by mixing poly(vinyl) chloride (PVC), 2- nitrophenyl octyl ether (NPOE), bis-thiourea derivative ionophore, tetradodecylammonium chloride (TDACl) and tetrahydofuran (THF) solvent. Then, the homogenous cocktail was deposited on top of Ppy film with 50% v/v methanol as solvent formed on top of SPE and dried overnight at room temperature. This phosphate sensor was tested using commercial Ag/AgCl double junction reference electrode. The results were shown in Table 1 and in FIG.6. All the results have shown satisfactory phosphate sensitivity value with good regression value more than 0.9.

Abstract

The present invention relates to an improved phosphate sensor comprising a substrate; a thick film screen printed carbon layer; a phosphate sensing membrane; polypyrole layer; characterized in that the polypyrole layer is homogeneously doped on the carbon layer.

Description

PHOSPHATE SENSOR
FIELD OF INVENTION
The present invention relates to an improved phosphate sensor for electrochemical sensing and method of preparing the same.
BACKGROUND OF THE INVENTION
Phosphorus (P) is a multivalent nonmetal element in the same with group nitrogen in the periodic table. It is found in nature in several allotropic forms, and is an essential element for the life of organism. Commonly, phosphorus can be found as phosphates, which consists of phosphorus atom bonded to four oxygen atoms. Phosphates are important substances in the human body. For example, calcium phosphate is a major structural component of teeth and bone. Phosphorus also is a part of DNA materials. The importance of phosphorus is not limited to human, it is also essential nutrient for early root development in plant. The phosphate levels in the organisms and environmental nowadays have been major concern over the years. The excessive amount of phosphate in human can cause problem to health, such as kidney damage and osteoporosis. Therefore, leaching of inorganic phosphates in the river from agricultural and industrial activity has led to eutrophication. The increasing of phosphate level could promote the growth of phosphate-dependent organisms such as algae on the water surface. These organisms use great amounts of oxygen in water and prevent the sunlight entering the water which will disrupt normal functioning of the ecosystem.
Traditionally silver-silver chloride (Ag/AgCl) electrode has been employed as the electrochemical transducer in chemical sensors and reference electrode. While the Ag/AgCl electrode works best in the bulky glass electrode equipped with
SUBSTITUTE SHEET comparatively large volume of liquid internal electrolyte, the miniaturized solid state version employs hydrophilic polymeric membrane as an internal layer. In a typical laboratory procedure, the internal layer is hydrated with certain concentration of the target analyte, to act as the reference concentration. Depending on storage condition and due to other factors like aging the concentration of the internal layer changes and thus causes the electrical signal to change. This requires frequent or daily calibration; else the sensor would transmit inaccurate data.
Daily calibration is difficult for field deployed integrated sensors. Another problem caused by the hydrophilic internal layer is its incompatibility with the sensing membranes. The sensing membrane is usually highly lipophilic and its adhesion to hydrated hydrophilic internal layer is marginal and this results in peeling of the sensing membrane. Conductive polymers have been introduced as electrochemical transducer and it has been shown that chemical sensors employing conductive polymer can produce fast response and stable signal without the use of additional internal layer. Polypyrrole, polythiophene and polyaniline have been used as conductive polymers for chemical sensors.
Polypyrole has been the most widely used due to numerous advantages. Doping the polypyrrole increases the conductivity of the conducting polymer and this is usually achieved by electropolymerization from solution of pyrrole monomer containing electrolyte of chloride or nitrate salts of potassium. This causes a problem because the doping electrolyte is aqueous solution, whereas the pyrrole monomer is only moderately soluble in this electrolyte. Therefore, vigorous shaking and continuous stirring are required to achieve homogenous mixture and to maintain homogeneity of the doped polypyrrole on a phosphate sensor. Hence, there is still a need in the art for an improved phosphate sensor for electrochemical sensing.
SUBSTITUTE SHEET SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided a phosphate sensor comprising:
a substrate,
a thick film screen printed carbon layer,
a phosphate sensing membrane;
polypyrole layer;
characterized in that the polypyrole layer is homogeneously doped on the carbon layer.
According to a second aspect of the invention, there is provided the phosphate sensor is used in the manufacture of an ion selective electrode (ISE) and an ion sensitive field effect transistor (ISFET) phosphate sensing device.
According to a third aspect of the invention, there is provided a method of depositing doped polypyrrole electrochemical transducer layer comprising;
a) preparing a pyrrole monomer doped electrolyte solution and a hydrophilic dopant in a polar solvent;
b) immersing a carbon electrode, a counter electrode and a reference electrode into the doped pyrrole electrolyte solution; and
c) depositing the doped polypyrrole electrochemically .
The provision of the method is advantageous as it results in producing a stable electrical signal and maintains homogeneity of the doped polypyrrole on a phosphate sensor.
SUBSTITUTE SHEET BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature of the present invention, reference should be made to the following detailed description taken in connection with the accompanying drawings in which:
FIG. 1: illustrates an electron transfer mechanism of phosphate ion inside the phosphate sensor with doped polypyrrole.
FIG.2: illustrates hydrophilic organic salts for polypyrrole doping.
FIG.3: illustrates a doped polypyrrole conducting polymer.
FIG.4: illustrates molecular structures of methyl methacrylate (2)
tetrahydrofurfuryl acrylate (3) monomers.
FIG.5: illustrates a cyclic voltammatograms of Ppy(Cl) from 50% v/v methanol solvent on Pt in 0.1M KC1 with 90, 150, 300 and 500 sec electropolymerisation time.
FIG.6: illustrates a potentiometric response of phosphate sensor with various electropolymerisation times.
SUBSTITUTE SHEET DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention relates to a miniaturized solid state phosphate sensor 10 as illustrated in FIG.l based on doped polypyrrole wherein the doping electrolytes are hydrophilic organic salts, as illustrated in FIG.2 dissolved in polar organic solvent, mixture of polar solvents or mixture of polar solvent and deionized water. In one embodiment, the miniaturized solid state phosphate sensor 10 based on doped polypyrrole electrochemical transducer that gives stable electrical signal. The phosphate sensor 10 does not require the use of hydrophilic internal layer and is easy to fabricate.
FIG.l shows a phosphate sensor 10 comprising; a substrate 50, a thick film screen printed carbon layer 40, a phosphate sensing membrane 20; polypyrrole layer 30; wherein the polypyrrole layer 30 is homogeneously doped on the carbon layer 40. FIG.l also shows that the polypyrrole conducting polymer 30 is deposited on top of screen printed thick film carbon 40 electrode. The carbon 40 surface must first be cleaned by sonication, and the pyrrole monomer is electropolymerized from the doping electrolyte. In one embodiment of the phosphate sensor 10, the doped polypyrrole layer 30 having doping electrolyte of the following structure;
Figure imgf000006_0001
1
X = CI, Br, I, BF4, PF6, OAc,CF3C02,N03, Fe(CN)6, oxalate, tosylate
n = 1 , 2, 3
R = H, methyl, ethyl, butyl, allyl
In one embodiment of the phosphate sensor 10, the phosphate sensing membrane 20 is photo-cured co-polymer of methyl methacrylate and tetrahydrofurfuryl acrylate
SUBSTITUTE SHEET containing photoinitiator, diacrylate crosslinker, lipophilic ammonium salt and phosphate ionophore.
In another embodiment of the phosphate sensor 10, the phosphate sensing membrane 20 is bulk co-polymer of methyl methacrylate and tetrahydrofurfuryl acrylate containing photoinitiator, diacrylate crosslinker, lipophilic ammonium salt and phosphate ionophore.
The phosphate sensor 10 of the present invention is usable in the manufacture of an ion selective electrode (ISE) phosphate sensing device. Also, the phosphate sensor 10 is usable in the manufacture of an ion sensitive field effect transistor (ISFET) phosphate sensing device.
The polymerization process of the pyrrole monomer releases two moles of electrons for each mole of the monomer. In the oxidized state polypyrrole exists as a polyradical cation, and at this state, anions such as chloride, are attracted electrostatically into the polymerized film as counter ions or dopants as illustrated in FIG.3.
The electrolytes of hydrophilic organic salts are prepared by dissolution in polar organic such as ethanol, methanol, 2-methoxy ethanol, dimethyl sulfoxide, acetonitrile or tetrahydrofuran. Mixture of polar organic solvents or mixture of the organic solvent and deionized water can also be used to dissolve the salts and the pyrrole monomer. Pyrrole exhibits very high solubility in these solvents and vigorous shaking or stirring is not required for mixing or in keeping homogeneity during electropolymerization.
A method of depositing doped polypyrrole electrochemical transducer layer comprising;
a) preparing a pyrrole monomer doped electrolyte solution and a hydrophilic dopant in a polar solvent;
b) immersing a carbon electrode, a counter electrode and a reference
electrode into the doped pyrrole electrolyte solution; and
SUBSTITUTE SHEET c) depositing the doped polypyrrole electrochemically .
In one example, in step (a) the pyrrole monomer doped electrolyte solution having concentration ranges from 0.1M to 3M of pyrrole monomer and the hydrophilic dopant in a polar solvent having a concentration ranges from 0.1M to 3M. Preferably, the hydrophilic dopant is choline chloride.
In one example, the depositing step (c) is by electrochemical polymerization of constant current method with current density of 0.1 to 10 raA per square centimetre.
In another example, the depositing step (c) is by electrochemical polymerization utilising cyclic voltammetry method with scans between -IV and +1 V.
In one example, pyrrole electropolymerization process takes place at the screen printed carbon 40 working electrode while conventional double-junction reference electrode and platinum or glassy carbon electrode counter electrode complete the chronopotentiometry setup.
Referring to FIG.4, co-polymer of acrylates, methyl methacrylate (2) and tetrahydrofiirfuryl acrylate (3) has been employed as the phosphate sensing membranes 20 based on doped polypyrrole. The monomers can be photo-polymerized from a cocktail containing the monomers, photoinitiator, crosslinker, lipophilic ammonium salt and phosphate ionophore. Likewise, bulk co-polymer of the above monomers can also be used as the sensing membrane 20. In another example of preparation, the bulk co-polymer is first synthesized by refluxing the desired ratios of the monomers and benzoyl peroxide in benzene. After purification and drying, samples from the bulk polymer are dissolved with methylene chloride or tetrahydrofuran, along with the above components for phosphate sensing membrane 20. A few microliters of the bulk cocktail is dispensed
SUBSTITUTE SHEET coated on the sonicated polypyrrole electrode and the solvent air dried before testing for phosphate response can be conducted.
Polypyrrole is a conducting polymer due to its conjugated network of double bonds. In this manner it acts as a molecular wire and thus employed to conduct electrical current. Polypyrrole has another property that is of interest in chemical sensing - it undergoes reversible oxidation-reduction cycle at well-defined potentials. This property allows the use of polypyrrole as electrochemical transducer in chemical and biosensors. Advantageously, the method of depositing doped polypyrrole electrochemical transducer layer increases the potential of obtaining homogeneously doped polypyrrole layer on the phosphate sensor.
Advantageously, the preparation of the phosphate sensor takes shorter time by utilizing the method of depositing doped polypyrrole electrochemical transducer layer.
The invention now being generally described, the same will be better understood by reference to the following detailed examples which are provided for purposes of illustration only and are not to be limiting of the invention unless so specified.
EXAMPLE 1
Phosphate sensor based on polypyrrole film doped with choline-CI in 50% Methanol/deionised water (varied electropolymerisation time) i) Formation of Polypyrrole film
The screen printed electrodes (SPE) with 4 mm diameter were cleaned ultrasonically with deionized water for 1 min. The electrochemical polymerization was performed in a conventional three-electrode cell with a platinum as auxiliary electrode and the Ag/AgCl double junction as reference electrode using Autolab PGSTAT MODEL 128N for 90, 150, 300 and 500 seconds. The polypyrrole (Ppy) films were generated with current density of 2 mA cm 2 in aqueous solution of 0.5M pyrrole
SUBSTITUTE SHEET monomer containing 1M choline chloride dopant and 50% v/v methanol solvent. After forming electropolymerisation, cyclic voltammetry experiments were conducted between -1.0 V and +1.0 V with a potential sweep rate of 100 mV sec"1 in 0.1M potassium chloride (KC1) solution. The plot is shown as in FIG.5.
(ii) Phosphate sensor fabrication
Phosphate cocktail were prepared by mixing poly(vinyl) chloride (PVC), 2- nitrophenyl octyl ether (NPOE), bis-thiourea derivative ionophore, tetradodecylammonium chloride (TDACl) and tetrahydofuran (THF) solvent. Then, the homogenous cocktail was deposited on top of Ppy film with 50% v/v methanol as solvent formed on top of SPE and dried overnight at room temperature. This phosphate sensor was tested using commercial Ag/AgCl double junction reference electrode. The results were shown in Table 1 and in FIG.6. All the results have shown satisfactory phosphate sensitivity value with good regression value more than 0.9.
Figure imgf000010_0001
Table 1 : Phosphate sensor response (50% v/v methanol platfrom) with varied polymerisation time Although the invention has been described with reference to particular embodiment, it is to be understood that the embodiment is merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiment that other arrangements may be devised without departing from the scope of the present invention as defined by the appended claims.
SUBSTITUTE SHEET

Claims

2. A phosphate sensor comprising:
a substrate;
a thick film screen printed carbon layer;
a phosphate sensing membrane;
polypyrole layer;
characterized in that the polypyrole layer is homogeneously doped carbon layer.
3. The phosphate sensor as claimed in Claim 1 , characterized in that the doped
polypyrrole layer having doping electrolyte of the following structure;
Figure imgf000011_0001
1
X = CI, Br, I , BF4, PF6, OAc,CF3C02,N03, Fe(CN)6, oxalate, tosylate
n = 1 , 2, 3
R = H, methyl, ethyl, butyl, ally!
4. The phosphate sensor as claimed in Claim 1, characterized in that the phosphate sensing membrane is photo-cured co-polymer of methyl methacrylate and tetrahydrofurfuryl acrylate containing photoinitiator, diacrylate crosslinker, lipophilic ammonium salt and phosphate ionophore.
5. The phosphate sensor as claimed in Claim 1, characterized in that the phosphate sensing membrane 12 is bulk co-polymer of methyl methacrylate and tetrahydrofurfuryl acrylate containing photoinitiator, diacrylate crosslinker, lipophilic ammonium salt and phosphate ionophore..
SUBSTITUTE SHEET
6. Use of the phosphate sensor according to any preceding claim in the manufacture of an ion selective electrode (ISE) phosphate sensing device.
7. Use of the phosphate sensor according to claim 1 to 4 in the manufacture of an ion sensitive field effect transistor (ISFET) phosphate sensing device.
8. A method of depositing doped polypyrrole electrochemical transducer layer
comprising;
a) preparing a pyrrole monomer doped electrolyte solution and a
hydrophilic dopant in a polar solvent;
b) immersing a carbon electrode, a counter electrode and a reference
electrode into the doped pyrrole electrolyte solution; and
c) depositing the doped polypyrrole electrochemically.
9. A method of depositing doped polypyrrole electrochemical transducer layer according to Claim 7, characterized in that in step (a) the pyrrole monomer doped electrolyte solution having concentration ranges from 0.1M to 3M of pyrrole monomer and the hydrophilic dopant in a polar solvent having a concentration ranges from 0.1M to 3M.
10. A method of depositing doped polypyrrole electrochemical transducer layer according to Claim 8, characterized in that the hydrophilic dopant is choline chloride.
1 1. A method of depositing doped polypyrrole electrochemical transducer layer according to Claim 7, characterized in that the depositing step (c) is by electrochemical polymerization of constant current method with current density of 0.1 to 10 mA per square centimetre.
12. A method of depositing doped polypyrrole electrochemical transducer layer according to Claim 4, characterized in that the depositing step (c) is by
SUBSTITUTE SHEET electrochemical polymerization utilising cyclic voltammetry method with between -IV and +1 V.
SUBSTITUTE SHEET
PCT/MY2011/000155 2010-12-03 2011-06-23 Phosphate sensor WO2012074368A1 (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014177856A1 (en) 2013-04-30 2014-11-06 Cranfield University A phosphate sensor, its use and its method of preparation
WO2016032314A1 (en) * 2014-08-28 2016-03-03 Mimos Berhad An egfet phosphate sensor device
WO2019033034A1 (en) * 2017-08-11 2019-02-14 Uwm Research Foundation, Inc. Composition, electrode, and fabrication method for phosphate sensing
CN113008965A (en) * 2021-03-04 2021-06-22 深圳大学 Preparation method and application of solid film phosphate radical ion selective electrode based on cobalt/pyrrole/mesoporous carbon

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014177856A1 (en) 2013-04-30 2014-11-06 Cranfield University A phosphate sensor, its use and its method of preparation
WO2016032314A1 (en) * 2014-08-28 2016-03-03 Mimos Berhad An egfet phosphate sensor device
WO2019033034A1 (en) * 2017-08-11 2019-02-14 Uwm Research Foundation, Inc. Composition, electrode, and fabrication method for phosphate sensing
CN113008965A (en) * 2021-03-04 2021-06-22 深圳大学 Preparation method and application of solid film phosphate radical ion selective electrode based on cobalt/pyrrole/mesoporous carbon

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