Arsenic contamination is a critical environmental issue that causes serious health problems, including skin lesions, cancer, and cardiovascular diseases in humans. Therefore, the World Health Organisation established a maximum permissible limit for Arsenic at 10 ppb. The widespread occurrence of arsenic-related health issues necessitates the development of efficient methods for detection. Although, there are various instrumental as well as colourimetric nanomaterial-based methods for the quantification of Arsenic, but these approaches have drawbacks, such as complex assay techniques requiring costly chemicals for different sample matrices, expensive instrumentation and low shelf life, as well as agglomeration issues with nanomaterials. In this study, a novel electrochemical sensor was developed by using a Multi-walled carbon nanotube-SPCE that was functionalized with APTES, followed by the modification using polyethylene-capped gold nanoparticles for selective sensing of Arsenic. The modified electrode was characterized using various techniques such as SEM, XPS, FTIR and DLS. The PEG-capped gold nanoparticle exhibited a surface Plasmon resonance peak at 530 nm and a polydispersity index (PDI) of 0.337, confirming the monodisperse nanoparticles. SEM characterization data showed the heterogeneity of the modified surface with uniform distribution of PEG-capped Gold nanoparticles that confirmed the successful modification of the electrode, which was further supported by the XPS and FTIR spectra showing various functional groups for electrochemical sensing. The electrochemical studies i.e. Cyclic Voltammetry (CV) was performed at optimized scan rate, i.e. 100 mV/s and peak potential (0.26 V) best suited for the efficient electron transfer kinetics, results showed a strong linear relationship (R2 = 0.99) for arsenic concentrations between 15 and 75 ppb, with a limit of detection (LOD) of 8 ppb and a sensitivity of 0.238818 µA µM−1 cm−2, making it suitable for low-level arsenic detection. The sensor remains unaffected and results showed no significant interference of common interfering ions Na+, K+, Cl−, Ca2+, PO43−, CO3−, HCO3−, Cd3+, and CrO42−. Further the developed sensor results were compared with known stanadard method for arsenic detection such as AAS and arsenic testing kit showing a good correlation (R2 = 0.99), with excellent reproducibility (RSD < 2%) hereby emphasising its superiority for arsenic sensing. Thus the developed PEG-capped gold nanoparticle-modified MWCNT-SPCE-based electrochemical sensor offers a rapid, robust, and highly sensitive platform for trace-level arsenic detection in water samples and such sensing plateform has great potential to further modifiy as multianalyte sensing array for other pollutant also.

Gold Nanoparticles Modified MWCNT Screen Printed Electrode Based Electrochemical Sensor for Arsenic Detection

期刊论文
发表日期：

2025年12月10日

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Rahul Khatkar,
Suman Nagpal

摘要

Arsenic contamination is a critical environmental issue that causes serious health problems, including skin lesions, cancer, and cardiovascular diseases in humans. Therefore, the World Health Organisation established a maximum permissible limit for Arsenic at 10 ppb. The widespread occurrence of arsenic-related health issues necessitates the development of efficient methods for detection. Although, there are various instrumental as well as colourimetric nanomaterial-based methods for the quantification of Arsenic, but these approaches have drawbacks, such as complex assay techniques requiring costly chemicals for different sample matrices, expensive instrumentation and low shelf life, as well as agglomeration issues with nanomaterials. In this study, a novel electrochemical sensor was developed by using a Multi-walled carbon nanotube-SPCE that was functionalized with APTES, followed by the modification using polyethylene-capped gold nanoparticles for selective sensing of Arsenic. The modified electrode was characterized using various techniques such as SEM, XPS, FTIR and DLS. The PEG-capped gold nanoparticle exhibited a surface Plasmon resonance peak at 530 nm and a polydispersity index (PDI) of 0.337, confirming the monodisperse nanoparticles. SEM characterization data showed the heterogeneity of the modified surface with uniform distribution of PEG-capped Gold nanoparticles that confirmed the successful modification of the electrode, which was further supported by the XPS and FTIR spectra showing various functional groups for electrochemical sensing. The electrochemical studies i.e. Cyclic Voltammetry (CV) was performed at optimized scan rate, i.e. 100 mV/s and peak potential (0.26 V) best suited for the efficient electron transfer kinetics, results showed a strong linear relationship (R² = 0.99) for arsenic concentrations between 15 and 75 ppb, with a limit of detection (LOD) of 8 ppb and a sensitivity of 0.238818 µA µM⁻¹ cm⁻², making it suitable for low-level arsenic detection. The sensor remains unaffected and results showed no significant interference of common interfering ions Na⁺, K⁺, Cl⁻, Ca²⁺, PO₄³⁻, CO₃⁻, HCO₃⁻, Cd³⁺, and CrO₄²⁻. Further the developed sensor results were compared with known stanadard method for arsenic detection such as AAS and arsenic testing kit showing a good correlation (R² = 0.99), with excellent reproducibility (RSD < 2%) hereby emphasising its superiority for arsenic sensing. Thus the developed PEG-capped gold nanoparticle-modified MWCNT-SPCE-based electrochemical sensor offers a rapid, robust, and highly sensitive platform for trace-level arsenic detection in water samples and such sensing plateform has great potential to further modifiy as multianalyte sensing array for other pollutant also.