Quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometrics

Controlled-potential in situ thin-layer spectropotentiometry was leveraged to generate visible/near-infrared (VIS/NIR) absorption spectral data sets for the development of chemometric models to quantify Np(III/IV/V/VI) oxidation states in HNO3. This technology would be valuable in laboratory studies...

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Main Authors: Luke R. Sadergaski, Hunter B. Andrews, Sara E. Gilson, Adam J. Parkison
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-12-01
Series:Frontiers in Nuclear Engineering
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fnuen.2023.1323372/full
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author Luke R. Sadergaski
Hunter B. Andrews
Sara E. Gilson
Adam J. Parkison
author_facet Luke R. Sadergaski
Hunter B. Andrews
Sara E. Gilson
Adam J. Parkison
author_sort Luke R. Sadergaski
collection DOAJ
description Controlled-potential in situ thin-layer spectropotentiometry was leveraged to generate visible/near-infrared (VIS/NIR) absorption spectral data sets for the development of chemometric models to quantify Np(III/IV/V/VI) oxidation states in HNO3. This technology would be valuable in laboratory studies and when monitoring process solutions to guide feed adjustments for radiochemical separations—the performance of which depends on oxidation state. This approach successfully isolated and stabilized Np species in pure (∼99%) oxidation states without compromising solution optical properties. Multivariate curve resolution–alternating least squares models were evaluated to resolve spectral and component concentrations from a scan that sequentially produced Np(VI), Np(V), Np(IV), and Np(III) spectra with mixtures of two valences at a time. Although it provided a useful approximation, the method was not able to quantitively resolve each component likely because of rotational ambiguity. Additionally, partial least squares regression models were built from artificial and electrochemically generated VIS/NIR spectral training sets to study the effect of interionic interactions on spectral characteristics. Models built with true Bi-chemical mixtures of coexisting Np oxidation states and spectra generated from additive combinations of pure end points had similar prediction performance. This methodology can be used to directly quantify Np concentration and the ratio of Np oxidation states and other actinides in remote settings such as hot cells.
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spelling doaj.art-7db1dbc2b48545bba08265a3a65abc852024-08-03T02:23:11ZengFrontiers Media S.A.Frontiers in Nuclear Engineering2813-34122023-12-01210.3389/fnuen.2023.13233721323372Quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometricsLuke R. SadergaskiHunter B. AndrewsSara E. GilsonAdam J. ParkisonControlled-potential in situ thin-layer spectropotentiometry was leveraged to generate visible/near-infrared (VIS/NIR) absorption spectral data sets for the development of chemometric models to quantify Np(III/IV/V/VI) oxidation states in HNO3. This technology would be valuable in laboratory studies and when monitoring process solutions to guide feed adjustments for radiochemical separations—the performance of which depends on oxidation state. This approach successfully isolated and stabilized Np species in pure (∼99%) oxidation states without compromising solution optical properties. Multivariate curve resolution–alternating least squares models were evaluated to resolve spectral and component concentrations from a scan that sequentially produced Np(VI), Np(V), Np(IV), and Np(III) spectra with mixtures of two valences at a time. Although it provided a useful approximation, the method was not able to quantitively resolve each component likely because of rotational ambiguity. Additionally, partial least squares regression models were built from artificial and electrochemically generated VIS/NIR spectral training sets to study the effect of interionic interactions on spectral characteristics. Models built with true Bi-chemical mixtures of coexisting Np oxidation states and spectra generated from additive combinations of pure end points had similar prediction performance. This methodology can be used to directly quantify Np concentration and the ratio of Np oxidation states and other actinides in remote settings such as hot cells.https://www.frontiersin.org/articles/10.3389/fnuen.2023.1323372/fullactinideoptical spectroscopymachine learningonline monitoringmultivariate analysis
spellingShingle Luke R. Sadergaski
Hunter B. Andrews
Sara E. Gilson
Adam J. Parkison
Quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometrics
Frontiers in Nuclear Engineering
actinide
optical spectroscopy
machine learning
online monitoring
multivariate analysis
title Quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometrics
title_full Quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometrics
title_fullStr Quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometrics
title_full_unstemmed Quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometrics
title_short Quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometrics
title_sort quantifying neptunium oxidation states in nitric acid through spectroelectrochemistry and chemometrics
topic actinide
optical spectroscopy
machine learning
online monitoring
multivariate analysis
url https://www.frontiersin.org/articles/10.3389/fnuen.2023.1323372/full
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AT saraegilson quantifyingneptuniumoxidationstatesinnitricacidthroughspectroelectrochemistryandchemometrics
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