A Fibre-Optic Platform for Sensing Nitrate Using Conducting Polymers
Monitoring nitrate ions is essential in agriculture, food industry, health sector and aquatic ecosystem. We show that a conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), can be used for nitrate sensing through a process in which nitrate ion uptake leads to oxidation of PEDOT and change o...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-12-01
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| Series: | Sensors |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1424-8220/21/1/138 |
| _version_ | 1797543324612034560 |
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| author | Soroush Shahnia Heike Ebendorff-Heidepriem Drew Evans Shahraam Afshar |
| author_facet | Soroush Shahnia Heike Ebendorff-Heidepriem Drew Evans Shahraam Afshar |
| author_sort | Soroush Shahnia |
| collection | DOAJ |
| description | Monitoring nitrate ions is essential in agriculture, food industry, health sector and aquatic ecosystem. We show that a conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), can be used for nitrate sensing through a process in which nitrate ion uptake leads to oxidation of PEDOT and change of its optical properties. In this study, a new platform is developed in which a single-mode fibre coated at the tip with PEDOT is used for nitrate sensing. A crucial step towards this goal is introduction of carbonate exposure to chemically reduced PEDOT to a baseline value. The proposed platform exhibits the change in optical behaviour of the PEDOT layer at the tip of the fibre as it undergoes chemical oxidation and reduction (redox). The change in optical properties due to redox switching varies with the intensity of light back reflected by the fibre coated with PEDOT. The proposed platform during oxidation demonstrates linear response for the uptake of nitrate ions in concentrations ranging between 0.2 and 40 parts per million (ppm), with a regression coefficient <inline-formula><math display="inline"><semantics><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>97</mn></mrow></semantics></math></inline-formula> and a detection limit of 6.7 ppm. The procedure for redox switching is repeatable as the back reflection light intensity reaches <inline-formula><math display="inline"><semantics><mrow><mo>±</mo><mn>1</mn><mo>.</mo><mn>5</mn><mo>%</mo></mrow></semantics></math></inline-formula> of the initial value after reduction. |
| first_indexed | 2024-03-10T13:43:55Z |
| format | Article |
| id | doaj.art-c7b95377e6f34b8f900a9238a87829fa |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T13:43:55Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-c7b95377e6f34b8f900a9238a87829fa2023-11-21T02:48:55ZengMDPI AGSensors1424-82202020-12-0121113810.3390/s21010138A Fibre-Optic Platform for Sensing Nitrate Using Conducting PolymersSoroush Shahnia0Heike Ebendorff-Heidepriem1Drew Evans2Shahraam Afshar3Laser Physics and Photonic Devices Laboratories, UniSA STEM, University of South Australia, Mawson Lakes, SA 5095, AustraliaARC Centre of Excellence for Nanoscale Biophotonics, Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, SA 5000, AustraliaFuture Industries Institute, University of South Australia, Mawson Lakes, SA 5095, AustraliaLaser Physics and Photonic Devices Laboratories, UniSA STEM, University of South Australia, Mawson Lakes, SA 5095, AustraliaMonitoring nitrate ions is essential in agriculture, food industry, health sector and aquatic ecosystem. We show that a conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), can be used for nitrate sensing through a process in which nitrate ion uptake leads to oxidation of PEDOT and change of its optical properties. In this study, a new platform is developed in which a single-mode fibre coated at the tip with PEDOT is used for nitrate sensing. A crucial step towards this goal is introduction of carbonate exposure to chemically reduced PEDOT to a baseline value. The proposed platform exhibits the change in optical behaviour of the PEDOT layer at the tip of the fibre as it undergoes chemical oxidation and reduction (redox). The change in optical properties due to redox switching varies with the intensity of light back reflected by the fibre coated with PEDOT. The proposed platform during oxidation demonstrates linear response for the uptake of nitrate ions in concentrations ranging between 0.2 and 40 parts per million (ppm), with a regression coefficient <inline-formula><math display="inline"><semantics><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>97</mn></mrow></semantics></math></inline-formula> and a detection limit of 6.7 ppm. The procedure for redox switching is repeatable as the back reflection light intensity reaches <inline-formula><math display="inline"><semantics><mrow><mo>±</mo><mn>1</mn><mo>.</mo><mn>5</mn><mo>%</mo></mrow></semantics></math></inline-formula> of the initial value after reduction.https://www.mdpi.com/1424-8220/21/1/138nitrate sensingoptical fibrePEDOTconducting polymer |
| spellingShingle | Soroush Shahnia Heike Ebendorff-Heidepriem Drew Evans Shahraam Afshar A Fibre-Optic Platform for Sensing Nitrate Using Conducting Polymers Sensors nitrate sensing optical fibre PEDOT conducting polymer |
| title | A Fibre-Optic Platform for Sensing Nitrate Using Conducting Polymers |
| title_full | A Fibre-Optic Platform for Sensing Nitrate Using Conducting Polymers |
| title_fullStr | A Fibre-Optic Platform for Sensing Nitrate Using Conducting Polymers |
| title_full_unstemmed | A Fibre-Optic Platform for Sensing Nitrate Using Conducting Polymers |
| title_short | A Fibre-Optic Platform for Sensing Nitrate Using Conducting Polymers |
| title_sort | fibre optic platform for sensing nitrate using conducting polymers |
| topic | nitrate sensing optical fibre PEDOT conducting polymer |
| url | https://www.mdpi.com/1424-8220/21/1/138 |
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