Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution Algorithm
Nitrate is a prominent pollutant in water bodies around the world. The isotopes in nitrate provide an effective approach to trace the sources and transformations of nitrate in water bodies. However, determination of isotopic composition by conventional analytical techniques is time-consuming, labori...
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| Format: | Article |
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MDPI AG
2023-01-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/2/567 |
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| author | Ke Wu Fei Ma Cuilan Wei Fangqun Gan Changwen Du |
| author_facet | Ke Wu Fei Ma Cuilan Wei Fangqun Gan Changwen Du |
| author_sort | Ke Wu |
| collection | DOAJ |
| description | Nitrate is a prominent pollutant in water bodies around the world. The isotopes in nitrate provide an effective approach to trace the sources and transformations of nitrate in water bodies. However, determination of isotopic composition by conventional analytical techniques is time-consuming, laborious, and expensive, and alternative methods are urgently needed. In this study, the rapid determination of <sup>15</sup>NO<sub>3</sub><sup>−</sup> in water bodies using Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR) coupled with a deconvolution algorithm and a partial least squares regression (<i>PLSR</i>) model was explored. The results indicated that the characteristic peaks of <sup>14</sup>NO<sub>3</sub><sup>−</sup>/<sup>15</sup>NO<sub>3</sub><sup>−</sup> mixtures with varied <sup>14</sup>N/<sup>15</sup>N ratios were observed, and the proportion of <sup>15</sup>NO<sub>3</sub><sup>−</sup> was negatively correlated with the wavenumber of absorption peaks. The <i>PLSR</i> models for nitrate prediction of <sup>14</sup>NO<sub>3</sub><sup>−</sup>/<sup>15</sup>NO<sub>3</sub><sup>−</sup> mixtures with different proportions were established based on deconvoluted spectra, which exhibited good performance with the ratio of prediction to deviation (<i>RPD</i>) values of more than 2.0 and the correlation coefficients (<i>R</i><sup>2</sup>) of more than 0.84. Overall, the spectra pretreatment by the deconvolution algorithm dramatically improved the prediction models. Therefore, FTIR-ATR combined with deconvolution and <i>PLSR</i> provided a rapid, simple, and affordable method for determination of <sup>15</sup>NO<sub>3</sub><sup>−</sup> content in water bodies, which would facilitate and enhance the study of nitrate sources and water environment quality management. |
| first_indexed | 2024-03-09T11:36:10Z |
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| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T11:36:10Z |
| publishDate | 2023-01-01 |
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| series | Molecules |
| spelling | doaj.art-b2e6d12927814349a23e47a629791a0b2023-11-30T23:41:39ZengMDPI AGMolecules1420-30492023-01-0128256710.3390/molecules28020567Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution AlgorithmKe Wu0Fei Ma1Cuilan Wei2Fangqun Gan3Changwen Du4College of Environment and Ecology, Jiangsu Open University, Nanjing 210017, ChinaThe State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences, Nanjing 210008, ChinaCollege of Environment and Ecology, Jiangsu Open University, Nanjing 210017, ChinaCollege of Environment and Ecology, Jiangsu Open University, Nanjing 210017, ChinaThe State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences, Nanjing 210008, ChinaNitrate is a prominent pollutant in water bodies around the world. The isotopes in nitrate provide an effective approach to trace the sources and transformations of nitrate in water bodies. However, determination of isotopic composition by conventional analytical techniques is time-consuming, laborious, and expensive, and alternative methods are urgently needed. In this study, the rapid determination of <sup>15</sup>NO<sub>3</sub><sup>−</sup> in water bodies using Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR) coupled with a deconvolution algorithm and a partial least squares regression (<i>PLSR</i>) model was explored. The results indicated that the characteristic peaks of <sup>14</sup>NO<sub>3</sub><sup>−</sup>/<sup>15</sup>NO<sub>3</sub><sup>−</sup> mixtures with varied <sup>14</sup>N/<sup>15</sup>N ratios were observed, and the proportion of <sup>15</sup>NO<sub>3</sub><sup>−</sup> was negatively correlated with the wavenumber of absorption peaks. The <i>PLSR</i> models for nitrate prediction of <sup>14</sup>NO<sub>3</sub><sup>−</sup>/<sup>15</sup>NO<sub>3</sub><sup>−</sup> mixtures with different proportions were established based on deconvoluted spectra, which exhibited good performance with the ratio of prediction to deviation (<i>RPD</i>) values of more than 2.0 and the correlation coefficients (<i>R</i><sup>2</sup>) of more than 0.84. Overall, the spectra pretreatment by the deconvolution algorithm dramatically improved the prediction models. Therefore, FTIR-ATR combined with deconvolution and <i>PLSR</i> provided a rapid, simple, and affordable method for determination of <sup>15</sup>NO<sub>3</sub><sup>−</sup> content in water bodies, which would facilitate and enhance the study of nitrate sources and water environment quality management.https://www.mdpi.com/1420-3049/28/2/567nitratenitrogen isotopeFTIR-ATRdeconvolution algorithm<i>PLSR</i> model |
| spellingShingle | Ke Wu Fei Ma Cuilan Wei Fangqun Gan Changwen Du Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution Algorithm Molecules nitrate nitrogen isotope FTIR-ATR deconvolution algorithm <i>PLSR</i> model |
| title | Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution Algorithm |
| title_full | Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution Algorithm |
| title_fullStr | Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution Algorithm |
| title_full_unstemmed | Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution Algorithm |
| title_short | Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution Algorithm |
| title_sort | rapid determination of nitrate nitrogen isotope in water using fourier transform infrared attenuated total reflectance spectroscopy ftir atr coupled with deconvolution algorithm |
| topic | nitrate nitrogen isotope FTIR-ATR deconvolution algorithm <i>PLSR</i> model |
| url | https://www.mdpi.com/1420-3049/28/2/567 |
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