Fabrication of Orange Fluorescent Boron-Doped Graphene Quantum Dots for Al3+ Ion Detection

Abstract

Aluminum is a kind of metal that we often encounter. It can also be absorbed by the human body invisibly and will affect our bodies to a certain extent, e.g., by causing symptoms associated with Alzheimer’s disease. Therefore, the detection of aluminum is particularly important. The methods to detect metal ions include precipitation methods and electrochemical methods, which are cumbersome and costly. Fluorescence detection is a fast and sensitive method with a low cost and non-toxicity. Traditional fluorescent nanomaterials have a high cost, high toxicity, and cause harm to the human body. Graphene quantum dots are a new type of fluorescent nanomaterials with a low cost and non-toxicity that can compensate for the defects of traditional fluorescent nanomaterials. In this paper, c-GQDs and o-GQDs with good performance were prepared by a bottom-up hydrothermal method using o-phenylenediamine as a precursor and citric acid or boric acid as modulators. They have very good optical properties: o-GQDs exhibit orange fluorescence under UV irradiation, while c-GQDs exhibits cyan fluorescence. Then, different metal ions were used for ion detection, and it was found that Al3+ had a good quenching effect on the fluorescence of the o-GQDs. The reason for this phenomenon may be related to the strong binding of Al3+ ions to the N and O functional groups of the o-GQDs and the rapid chelation kinetics. During the chelation process, the separation of o-GQDs’ photoexcited electron hole pairs leads to their rapid electron transfer to Al3+, in turn leading to the occurrence of a fluorescence-quenching phenomenon. In addition, there was a good linear relationship between the concentration of the Al3+ ions and the fluorescence intensity, and the correlation coefficient of the linear regression equation was 0.9937. This illustrates the potential for the wide application of GQDs in sensing systems, while also demonstrating that Al3+ sensors can be used to detect Al3+ ions.

Facile fabrication of boron and nitrogen co-doped carbon dots for “ON–OFF–ON” fluorescence sensing of Al3+ and F− ions in water samples

“…S1e † explores the HR-XPS of B 1s with main bands at 190.3 eV, 191.2 eV, 192.4 eV, 195.6 eV, assigning to B–C, B O, Bi 2 O 3 , and B–O, respectively. 33 …”

“…S1a † shows the full XPS spectrum of BN@CDs with the corresponding C 1s, N 1s, O 1s, and B 1s peaks. 33 The optical characteristics of BN@CDs were studied using spectrophotometry and uorescence spectroscopy (Fig. 2).…”

Recent Advances in Photoswitchable Fluorescent and Colorimetric Probes

“…For example, in environmental monitoring, changes in the concentration of Al 3+ can reflect soil acidification and the extent of water pollution. In biomedicine, abnormal concentrations of aluminum ions are often associated with neurodegenerative diseases such as Alzheimer’s disease [ 104 , 105 ]. Therefore, developing methods to accurately monitor Al 3+ is of significant application value.…”

A dysprosium(iii)-based triple helical-like complex as a turn-on/off fluorescence sensor for Al(iii) and 4,5-dimethyl-2-nitroaniline

“…3,4 A series of pathological diseases have been proved to be inseparable from the disturbance of Al 3+ ion concentration balance, such as osteoporosis, anemia, and Alzheimer's disease. [5][6][7][8] In addition, long-term exposure to environments containing high concentrations of Al 3+ ions can cause permanent damage to the central nervous system, bones, and the hematopoietic system in humans. [9][10][11] Likewise, nitroaromatic compounds (NACs) are not only notorious environmental pollutants but also the basic constituent of nitroaromatic explosives, which pose a great threat to human health and public security.…”