Graphene/fluorescein dye-based sensor for detecting As(III) in drinking water

Madhu D Sharma,Reddithota J Krupadam,Spas D Kolev,Sadhana S Rayalu

doi:10.1038/s41598-021-96968-3

Abstract

A complex of reduced graphene oxide (rGO) and fluorescein (FL) dye nanoparticles of size between 50 and 100 nm has been prepared and its sensing performance for detection of As(III) in drinking water has been reported. When As(III) binds to the rGO–FL nanoparticles the relative quenching of fluorescence was increased with increase in As(III) concentration thus provide two linear calibration ranges (0–4.0 mmol L−1 and 4.0–10 mmol L−1). The fluorescence quenching mechanism was investigated by using time-resolved fluorescence spectroscopy and molecular modeling. The detection limit of this sensor has been determined as equal to 0.96 µg L−1 which is about 10 times lower than the WHO stipulated standard for As(III) in drinking water (10 µg L−1). The analytical performance and potential application of the nanosensor was compared to commercial field kits used in arsenic monitoring. The sensor proposed in this study is fast, sensitive and accurate for detection of As(III) in drinking water and environmental samples.

Highlights

Contamination of drinking water with toxic arsenic species has been reported across the g lobe[1,2]
The surface area of reduced graphene oxide (rGO) without FL was 182 m2 g−1 and higher surface area was attributed to the higher hydrophilicity of the rGO–FL nanoparticles which facilitated their aggregation in water
It can be hypothesized that these cavities could be preferentially binding with As(III) species (Fig. 2d)

Summary

Introduction

Contamination of drinking water with toxic arsenic species has been reported across the g lobe[1,2]. The testing of drinking water for arsenic species such low concentration is a challenge to analysts. Sophisticated instrumental techniques such as inductively coupled plasma mass spectrometry (ICP-MS) are often used to determine ultra-trace concentrations of arsenic species in water[5]. This method is expensive and not fit for in-situ analysis. An aptamer based fluorimetric method has offered an impressively low detection limit of 1.3 pmol L −1 for As(III) In this method, the highly toxic cadmium ion was used as the aptamer conjugate to generate fluorescence signal. The media used in this method for As(III) analysis are organic solutions which limits application of this

Methods

Results

Conclusion