Development of Graphene Quantum Dots-Based Optical Sensor for Toxic Metal Ion Detection

Abstract

About 71% of the Earth’s surface is covered with water. Human beings, animals, and plants need water in order to survive. Therefore, it is one of the most important substances that exist on Earth. However, most of the water resources nowadays are insufficiently clean, since they are contaminated with toxic metal ions due to the improper disposal of pollutants into water through industrial and agricultural activities. These toxic metal ions need to be detected as fast as possible so that the situation will not become more critical and cause more harm in the future. Since then, numerous sensing methods have been proposed, including chemical and optical sensors that aim to detect these toxic metal ions. All of the researchers compete with each other to build sensors with the lowest limit of detection and high sensitivity and selectivity. Graphene quantum dots (GQDs) have emerged as a highly potential sensing material to incorporate with the developed sensors due to the advantages of GQDs. Several recent studies showed that GQDs, functionalized GQDs, and their composites were able to enhance the optical detection of metal ions. The aim of this paper is to review the existing, latest, and updated studies on optical sensing applications of GQDs-based materials toward toxic metal ions and future developments of an excellent GQDs-based SPR sensor as an alternative toxic metal ion sensor.

Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing

“…Due to these properties, GQDs have been investigated for possible applications in sensing [14][15][16][17]. As fluorescent probes, GQDs were investigated for the detection of metal ions, pesticides or other organic species [14].…”

“…Amines are one of the most well-known examples of biomolecules whose presence and concentration is related to the quality of food matrices [23]; several colorimetric strategies have been reported and reviewed in the literature, based on the evolution of either light absorption [24][25][26] or emission features [27,28]. In the case of optical sensing, information can be retrieved focusing on GQDs absorbance and fluorescent emissions; thus, modification of absorbance intensity, or fluorescence quenching efficiency is a well-assessed tool for revealing an analyte, as a result of interaction between GQDs probe and investigated species [16]. In contrast to different methods for the detection of metal ions, such as atomic absorption, plasma-mass and plasma-atomic emission spectroscopies, the fluorescent probes with GQDs have higher sensitivity and selectivity [29].…”

“…In contrast to different methods for the detection of metal ions, such as atomic absorption, plasma-mass and plasma-atomic emission spectroscopies, the fluorescent probes with GQDs have higher sensitivity and selectivity [29]. Other advantages of this approach are dispersibility in aqueous solution, low-cost, good reproducibility and biocompatibility [16].…”

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

“…A promising tool are quantum dots (QDs) which can be described as objects of the size below 10 nm with unique properties [1][2][3][4]. Since their development, they have been successfully used in optoelectronics [1], food packaging [5], metals detection [6][7][8], bioimaging [9][10][11][12][13][14], photocatalysis [15,16], sensing [17][18][19][20][21][22][23], cell labelling [24], or fluorescent inks and others [25,26]. The first-generation quantum dots are semiconductors of crystalline structure [3].…”

Antioxidant Activity of Graphene Quantum Dots Prepared in Different Electrolyte Environments

“…As a quasi-zero-dimensional carbon nanomaterial, graphene quantum dots (GQDs) have stable fluorescence [10][11][12], water solubility [13], excellent biocompatibility [14,15], and low cytotoxicity [16][17][18]. Thus, it exhibits great application potential in the fields of bio-imaging [19], catalysis [20,21], desalination [22][23][24], plasmonics [25][26][27][28], and sensing [29]. Moreover, the antioxidant activity of GQDs has received much attention [1,30].…”