Rapid Detection of Aluminium and Iron Impurities in Lithium Carbonate Using Water-Soluble Fluorescent Probes

The real-time measurement of the content of impurities such as iron and aluminium ions is one of the keys to quality evaluation in the production process of high-purity lithium carbonate; however, impurity detection has been a time-consuming process for many years, which limits the optimisation of t...

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Main Authors: Hong-Mei Wu, Huai-Gang Cheng, Zi-Wen Zhu, Li Cui
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/1/135
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author Hong-Mei Wu
Huai-Gang Cheng
Zi-Wen Zhu
Li Cui
author_facet Hong-Mei Wu
Huai-Gang Cheng
Zi-Wen Zhu
Li Cui
author_sort Hong-Mei Wu
collection DOAJ
description The real-time measurement of the content of impurities such as iron and aluminium ions is one of the keys to quality evaluation in the production process of high-purity lithium carbonate; however, impurity detection has been a time-consuming process for many years, which limits the optimisation of the production of high-purity lithium carbonate. In this context, this work explores the possibility of using water-soluble fluorescent probes for the rapid detection of impurity ions. Salicylaldehyde was modified with the hydrophilic group <span style="font-variant: small-caps;">dl</span>-alanine to synthesise a water-soluble Al<sup>3+</sup> fluorescent probe (Probe A). Moreover, a water-soluble Fe<sup>3+</sup> fluorescent probe (Probe B) was synthesised from coumarin-3-carboxylic acid and 3-hydroxyaminomethane. Probe A and Probe B exhibited good stability in the pH range of 4–9 in aqueous solutions, high sensitivity, as well as high selectivity for Al<sup>3+</sup> and Fe<sup>3+</sup>; the detection limits for Al<sup>3+</sup> and Fe<sup>3+</sup> were 1.180 and 1.683 μmol/L, whereas the response times for Al<sup>3+</sup> and Fe<sup>3+</sup> were as low as 10 and 30 s, respectively. Electrostatic potential (ESP) analysis and density functional theory calculations identified the binding sites and fluorescence recognition mechanism; theoretical calculations showed that the enhanced fluorescence emission of Probe A when detecting Al<sup>3+</sup> was due to the excited intramolecular proton transfer (ESIPT) effect, whereas the fluorescence quenching of Probe B when detecting Fe<sup>3+</sup> was due to the electrons turning off fluorescence when binding through the photoelectron transfer (PET) mechanism.
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spelling doaj-art-25a00a4e3aed4e3993fd85d3a197aaed2025-01-10T13:18:59ZengMDPI AGMolecules1420-30492024-12-0130113510.3390/molecules30010135Rapid Detection of Aluminium and Iron Impurities in Lithium Carbonate Using Water-Soluble Fluorescent ProbesHong-Mei Wu0Huai-Gang Cheng1Zi-Wen Zhu2Li Cui3Salt Lake Chemical Engineering Research Complex, Qinghai University, Xining 810016, ChinaSalt Lake Chemical Engineering Research Complex, Qinghai University, Xining 810016, ChinaInstitute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030032, ChinaInstitute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030032, ChinaThe real-time measurement of the content of impurities such as iron and aluminium ions is one of the keys to quality evaluation in the production process of high-purity lithium carbonate; however, impurity detection has been a time-consuming process for many years, which limits the optimisation of the production of high-purity lithium carbonate. In this context, this work explores the possibility of using water-soluble fluorescent probes for the rapid detection of impurity ions. Salicylaldehyde was modified with the hydrophilic group <span style="font-variant: small-caps;">dl</span>-alanine to synthesise a water-soluble Al<sup>3+</sup> fluorescent probe (Probe A). Moreover, a water-soluble Fe<sup>3+</sup> fluorescent probe (Probe B) was synthesised from coumarin-3-carboxylic acid and 3-hydroxyaminomethane. Probe A and Probe B exhibited good stability in the pH range of 4–9 in aqueous solutions, high sensitivity, as well as high selectivity for Al<sup>3+</sup> and Fe<sup>3+</sup>; the detection limits for Al<sup>3+</sup> and Fe<sup>3+</sup> were 1.180 and 1.683 μmol/L, whereas the response times for Al<sup>3+</sup> and Fe<sup>3+</sup> were as low as 10 and 30 s, respectively. Electrostatic potential (ESP) analysis and density functional theory calculations identified the binding sites and fluorescence recognition mechanism; theoretical calculations showed that the enhanced fluorescence emission of Probe A when detecting Al<sup>3+</sup> was due to the excited intramolecular proton transfer (ESIPT) effect, whereas the fluorescence quenching of Probe B when detecting Fe<sup>3+</sup> was due to the electrons turning off fluorescence when binding through the photoelectron transfer (PET) mechanism.https://www.mdpi.com/1420-3049/30/1/135lithium carbonatefluorescent probeswater solubilitymetal ionsdetection
spellingShingle Hong-Mei Wu
Huai-Gang Cheng
Zi-Wen Zhu
Li Cui
Rapid Detection of Aluminium and Iron Impurities in Lithium Carbonate Using Water-Soluble Fluorescent Probes
Molecules
lithium carbonate
fluorescent probes
water solubility
metal ions
detection
title Rapid Detection of Aluminium and Iron Impurities in Lithium Carbonate Using Water-Soluble Fluorescent Probes
title_full Rapid Detection of Aluminium and Iron Impurities in Lithium Carbonate Using Water-Soluble Fluorescent Probes
title_fullStr Rapid Detection of Aluminium and Iron Impurities in Lithium Carbonate Using Water-Soluble Fluorescent Probes
title_full_unstemmed Rapid Detection of Aluminium and Iron Impurities in Lithium Carbonate Using Water-Soluble Fluorescent Probes
title_short Rapid Detection of Aluminium and Iron Impurities in Lithium Carbonate Using Water-Soluble Fluorescent Probes
title_sort rapid detection of aluminium and iron impurities in lithium carbonate using water soluble fluorescent probes
topic lithium carbonate
fluorescent probes
water solubility
metal ions
detection
url https://www.mdpi.com/1420-3049/30/1/135
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AT ziwenzhu rapiddetectionofaluminiumandironimpuritiesinlithiumcarbonateusingwatersolublefluorescentprobes
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