Mentha-Stabilized Silver Nanoparticles for High-Performance Colorimetric Detection of Al(III) in Aqueous Systems

Rekha Sharma,Ankita Dhillon,Dinesh Kumar

doi:10.1038/s41598-018-23469-1

Rekha Sharma, Ankita Dhillon + Show 1 more

Open Access

https://doi.org/10.1038/s41598-018-23469-1

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Abstract

The present paper reports a facile and selective colorimetric method for the detection of potential environmental and health hazardous metal ions using green synthesized silver nanoparticles (AgNPs). Here the organic functional groups present in the plant extract (Mentha arvensis) are used as reductants and stabilizers in the synthesis of AgNPs. They also provide a suitable binding site to the (Al(III)) analyte in the detection mechanism. The leaf extract of Mentha arvensis was used to synthesize AgNPs at room-temperature and at 80 °C. The AgNPs synthesized at 80 °C exhibit excellent selective colorimetric detection of Al(III). The as-synthesized AgNPs have been characterized, and the synthesis, stabilization of NPs and detection mechanism has also been illustrated by using UV-vis, XPS, FTIR, TEM, EDX, SEM, AAS, and TGA analytical tools and techniques. The selectivity of detection probe was supported by the reaction between probe and metal ions followed first-order kinetics having the highest value of the regression coefficient (R2 = 0.99) for Al(III) and the analysis of thermodynamic parameters. The prepared sensor showed a lower limit of detection (LOD) of 1 nM (S/N = 3.2) in real water samples. The proposed method can be successfully utilized for the detection of Al(III) from both drinking and real water samples at the nanomolar level.

Highlights

As paper-based analytical device (PAD), quantum-dots-based photoelectrochemical immune assays, magnetic bead-based reverse colorimetric sensors, MnO2 nanoflakes with enzyme cascade amplification for colorimetric immunoassay, Fenton reaction-based colorimetric immunoassay for sensitive detection of brevetoxin B have been synthesized for the colorimetric detection of metal ions in aqueous system[23,24,25,26,27,28]
A characteristic Surface Plasmon Resonance (SPR) peak appears at 419 nm, corresponding to the dark yellow solution of M-AgNPs (Fig. 1a) that indicates the formation of M-AgNPs
The stretching vibrations due to the aromatic ring of Mentha were obtained at 1630.45 cm−1; a single absorbance peak located at 1176.98 cm−1 is assigned to C-O polyols; a peak around 2657.49 cm−1 corresponds to carbonyl (C=O) group while broadband at 3334.03 cm−1 corresponds to the O-H group

Summary

Introduction

As paper-based analytical device (PAD), quantum-dots-based photoelectrochemical immune assays, magnetic bead-based reverse colorimetric sensors, MnO2 nanoflakes with enzyme cascade amplification for colorimetric immunoassay, Fenton reaction-based colorimetric immunoassay for sensitive detection of brevetoxin B have been synthesized for the colorimetric detection of metal ions in aqueous system[23,24,25,26,27,28]. In continuation of our research interest in the development of more efficient methods, we have studied the application of AgNPs functionalized with the leaf extract of Mentha (M-AgNPs) for the highly selective and sensitive detection of aqueous Al(III) with 1 nM level. The flavonoids have the good reducing capacity, the moment they come in contact with Ag(I) ions, they transfer their π-electrons and reduce the Ag(I) to Ag(0). They help in preventing agglomeration thereby stabilizing the AgNPs36. The present study aims to detect Al(III) with a visual color change as compared to other environmentally relevant metal ions. The Al(III) ions’ interaction with M-AgNPs has been established by X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Zeta potential and Energy Dispersive X-ray (EDS) spectroscopy studies

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