Polychromatic Carbon Dots Prepared from m-Phenylenediamine and Urea as Multifunctional Fluorescent Probes

Abstract

The use of nanomaterials such as carbon dots (CDs) as rapid detection fluorescent nanoprobes is a hot topic in the field of analytical chemistry. In this paper, blue, green, and red CDs with high fluorescence quantum yields (24, 54, and 38%, respectively) were obtained from m-phenylenediamine and urea by hydrothermal synthesis and chromatographic separation. After investigating the structures and properties of the obtained CDs, three distinct and sensitive fluorescent nanoprobes with different functions were successfully constructed. The first nanoprobe derived from blue CDs could be used to detect the pH of a strong acid solution (pH 3.0); a rapid detection kit was designed based on it. The second nanoprobe based on Green CDs with ellagic acid (EA) modification allowed the sensitive determination of Fe3+ ions in aqueous solutions. The final probe derived from Red CDs could be used to test for organic acids in liquor. The test results of the commercial liquor were consistent with the standard methods. The detection mechanism of the three fluorescent probes was proposed. Using CDs to construct multifunctional fluorescent nanoprobes is beneficial for the application of CDs to rapid and specific detection and recognition.

High luminescent N,S,P co-doped carbon dots for the fluorescence sensing of extreme acidity and folic acid

“…1e) can be divided into three peaks of 284.30, 285.0 and 285.77 eV, corresponding to CC/C–H, C–N and CO/C–O, respectively. 46,47 The binding energies of graphite nitrogen and pyrrole nitrogen peaks are located at 399.3 and 401.1 eV, respectively 48 (Fig. 1f).…”

Photoluminescence Mechanism of Carbon Dots: Triggering Multiple Color Emissions through Controlling the Degree of Protonation

“…In Figure 3 B, the position of C=N red shifts from 1606.9 cm −1 to 1625.3 cm −1 for 14–CDs to 2–CDs. The above phenomena indicate that with the deepening of the protonation degree of the source m−PD, the content of C=N double bonds increases [ 35 ]. The absorption characteristics of 2–CDs, 7–CDs, 10–CDs and 14–CDs were studied by UV-vis absorption spectra ( Figure 3 C).…”

High sensitive assay of formaldehyde using resonance light scattering technique based on carbon dots aggregation

“…S5a, in Supporting Information). Nitrogen-doped CDs (N-CDs)are usually amino-rich CDs, are these CDs all suitable to detect FA by RLS through Schiff-base reactionThe N-CDs were obtained using the previous method (Arkin et al, 2021). When FA solutions (4 nM-400 lM) were added to the N-CDs solution, the RLS signal of the N-CDs has not distinct change (Fig.…”