Laser-Based Synthesis of Au Nanoparticles for Optical Sensing of Glyphosate: A Preliminary Study.

Antonella Laura Sortino,Vittorio Privitera,Gabriella Munzi,Maria Censabella,Simona Boninelli,Francesco Ruffino

doi:10.3390/mi11110989

Antonella Laura Sortino, Vittorio Privitera + Show 4 more

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https://doi.org/10.3390/mi11110989

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Abstract

Nowadays, Au nanoparticles (AuNPs) capture great interest due to their chemical stability, optical properties, and biocompatibility. The success of technologies based on the use of AuNPs implies the development of simple synthesis methods allowing, also, the fine control over their properties (shape, sizes, structure). Here, we present the AuNPs fabrication by nanosecond pulsed laser ablation in citrate-solution, that has the advantage of being a simple, economic and eco-sustainable method to fabricate colloidal solutions of NPs. We characterized the stability and the absorbance of the solutions by Ultraviolet-Visible (UV-Vis) spectroscopy and the morphology of the AuNPs by Transmission Electron Microscopy. In addition, we used the AuNPs solutions as colorimetric sensor to detect the amount of glyphosate in liquid. Indeed, glyphosate is one of the most widely used herbicides which intensive use represents a risk to human health. The glyphosate presence in the colloidal AuNPs solutions determines the aggregation of the AuNPs causing the change in the color of the solution. The variation of the optical properties of the colloidal solutions versus the concentration of glyphosate is studied.

Highlights

In recent years, the advent of nanotechnology has allowed a widespread use of nanostructures in the industrial, biological, biomedical, fuel cells, and optical fields, this thank their unique chemical and physical properties related to large surface/volume ratio respect to bulk materials [1,2,3,4]
As a preliminary study towards in-depth future investigations, we report on the use of the citrate-capped Au nanoparticles (AuNPs) in water solution to detect the amount of glyphosate in water exploiting the color change of the solutions and their absorbance spectrum due to glyphosate’s presence
Citrate-capped AuNPs have been produced by Pulsed Laser Ablation in Liquid environment (PLAL) at different ablation times

Summary

Introduction

The advent of nanotechnology has allowed a widespread use of nanostructures in the industrial, biological, biomedical, fuel cells, and optical fields, this thank their unique chemical and physical properties related to large surface/volume ratio respect to bulk materials [1,2,3,4]. Particular interest is directed towards metallic nanoparticles and especially noble metal nanoparticles (Au, Pt, Pd, Ag, Rh, Ru, Ir, and Os) that show unique properties, such as resistance to corrosion and oxidation, high melting point, non-reactiveness, and high ionization energy [5,6,7,8,9,10,11,12,13]. Under excitation by electromagnetic radiation, Au and Ag present localized surface plasmon resonance (LSPR) [2,11,20,21,22], i.e., collective oscillations of free-electrons. A strong absorption band appears in some region of the electromagnetic spectrum, which lead to unique properties, such as strong resonant absorption/scattering, intense field enhancement, ultrasensitive biosensing, which makes them highly interesting for multiple purposes [23,24].

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