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<p>Arsenite (As(III)) contamination in drinking water presents a significant risk to human health, creating an urgent need for rapid, sensitive, and cost-effective monitoring strategies. In this study a fluorescence-based sensing platform is developed using graphene quantum dots (GQDs) functionalized with polyethylene glycol (PEG) and chitosan for the selective detection of As(III) in aqueous media. The combined PEG–chitosan functionalization improves colloidal stability and provides abundant surface binding sites, facilitating efficient interaction between As(III) and the GQD surface. Fluorescence quenching occurs through coordination of As(III) with surface –NH₂ and –OH groups, inducing non-radiative photoinduced electron transfer (PET).The sensor exhibits a low limit of detection of 0.0093 ppm, with a linear response over environmentally relevant concentration ranges, including the World Health Organization guideline value for arsenic in drinking water. Time-resolved photoluminescence measurements reveal an ultrafast fluorescence lifetime of 2.21 ns, indicating efficient excited-state quenching upon As(III) interaction. Real-sample analysis demonstrates high accuracy, selectivity, and reproducibility (RSD = 1.3%), with negligible interference from common coexisting ions such as Na⁺, Ca²⁺, and Mg²⁺. Fluorescence response is maintained across a broad pH range, confirming suitability for practical water analysis. Principal component analysis (PCA) and non-negative least squares (NNLS) were applied exclusively as post-acquisition chemometric tools to enhance spectral discrimination and signal reliability, without influencing sensor chemistry or material design. The integration of biowaste-derived GQDs with synergistic PEG–chitosan functionalization provides a scalable, and low-cost fluorescence sensing platform, offering a practical alternative to conventional laboratory-based methods for on-site As(III) monitoring in water systems.</p>

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Fluorescence Quenching–Based Detection of Arsenite (As(III)) Using a PEG–Chitosan Functionalized Graphene Quantum Dot Nanocomposite

  • 期刊论文

  • 发表日期：

    2026年2月25日

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  • Shivani Pandey,
  • Satanand Mishra,
  • Tanmay Sardar

摘要

Arsenite (As(III)) contamination in drinking water presents a significant risk to human health, creating an urgent need for rapid, sensitive, and cost-effective monitoring strategies. In this study a fluorescence-based sensing platform is developed using graphene quantum dots (GQDs) functionalized with polyethylene glycol (PEG) and chitosan for the selective detection of As(III) in aqueous media. The combined PEG–chitosan functionalization improves colloidal stability and provides abundant surface binding sites, facilitating efficient interaction between As(III) and the GQD surface. Fluorescence quenching occurs through coordination of As(III) with surface –NH₂ and –OH groups, inducing non-radiative photoinduced electron transfer (PET).The sensor exhibits a low limit of detection of 0.0093 ppm, with a linear response over environmentally relevant concentration ranges, including the World Health Organization guideline value for arsenic in drinking water. Time-resolved photoluminescence measurements reveal an ultrafast fluorescence lifetime of 2.21 ns, indicating efficient excited-state quenching upon As(III) interaction. Real-sample analysis demonstrates high accuracy, selectivity, and reproducibility (RSD = 1.3%), with negligible interference from common coexisting ions such as Na⁺, Ca²⁺, and Mg²⁺. Fluorescence response is maintained across a broad pH range, confirming suitability for practical water analysis. Principal component analysis (PCA) and non-negative least squares (NNLS) were applied exclusively as post-acquisition chemometric tools to enhance spectral discrimination and signal reliability, without influencing sensor chemistry or material design. The integration of biowaste-derived GQDs with synergistic PEG–chitosan functionalization provides a scalable, and low-cost fluorescence sensing platform, offering a practical alternative to conventional laboratory-based methods for on-site As(III) monitoring in water systems.