Synthesis of nitrogen-doped and amino acid-functionalized graphene quantum dots from glycine, and their application to the fluorometric determination of ferric ion

Abstract

We report on a single-step thermolysis strategy to prepare highly luminescent nitrogen-doped and amino acidfunctionalized graphene quantum dots (NA-GQDs) by using glycine as both carbon and nitrogen source. The NA-GQDs display an excitation wavelength-dependent fluorescence with maximum excitation and emission wavelengths of 380 and 450 nm, respectively, and a quantum yield of~16 %. Fluorescence is quenched by Fe(III) and Hg(II), and the effect was used to develop a method for the determination of Fe(III). Quenching by Fe(III) is attributed to its higher thermodynamic affinity (compared to other transition-metal ions) for the ligands on the GQDs in which nitrogen atoms mainly act as the chelating atoms. A linear relationship was observed between fluorescence intensity and the concentration of Fe(III) over the 0.5 μM to 0.5 mM range. The detection limit is 0.1 μM.

Fluorescence quenchometric method for determination of ferric ion using boron-doped carbon dots

“…Since Fe 3+ can effectively quench the fluorescence of CDs [19][20][21][22][23][24][25][26], the capability of the current B-CDs as fluorescent probe to quantitatively detect Fe 3+ was also investigated. Figure 4b presents the relationship between the concentration of Fe 3+ ions and the relative fluorescent intensity (F/F 0 ) (F 0 and F are the fluorescence intensity at 359 nm in the absence and presence of ions, respectively).…”

“…Among these methods, fluorescence detection is a favorable method due to their high sensitivity, selectivity and fast detection. The increasing probes based on fluorescence quenching response of CDs have been studied recently [19][20][21][22][23][24][25][26]. All the probes show high sensitivity to Fe 3+ , however, some of them exhibit relatively poor selectivity due to the presence of Ag + [19], Pb 2+ [19,21], Hg 2+ [22,26], and Cu 2+ [25].…”

“…Therefore, accurate and fast determination of Fe(III) is an important issue in the environment and in biological systems. Up to now, numerous methods have been developed for the detection of Fe(III), including flame atomic absorption spectroscopy [14], mass spectrometry [15], electrochemical [16], and fluorescence detection [17][18][19][20][21][22][23][24][25][26]. Among these methods, fluorescence detection is a favorable method due to their high sensitivity, selectivity and fast detection.…”

Ultrafast ammonia-driven, microwave-assisted synthesis of nitrogen-doped graphene quantum dots and their optical properties

“…For example, NGQDs have been synthesized using glycine [21], glucose [14], or citric acid [22][23][24][25][26][27] as carbon source or using ammonia [14,22,23], dicyandiamide [24,25], tris(hydroxymethyl) aminomethane [26], 3,4-dihydroxy-L-phenylalanine [27], or glycine [21] as nitrogen source through hydrothermal reaction [14,[21][22][23][24][25] or high-temperature treatment [26,27]. Such one-step methods usually require high temperature and/ or high pressure.…”

Fe3+-functionalized carbon quantum dots: A facile preparation strategy and detection for ascorbic acid in rat brain microdialysates

“…To explore the selectivity of this fluorescence probe, the fluorescence intensity ratios F/F 0 (F and F 0 refer to the fluorescence intensities of Fe 3+ -functionalized CQDs at 445 nm in the presence and absence of different interference, respectively) of because of FRET or weak interactions including chelation [41], hydrogen bonds [10] or etching effects [23]. It further indicates that this method can be used to detect AA in the presence of potential interfering substances in a biological environment or in biological samples.…”