Doped Carbon Quantum Dots/PVA Nanocomposite as a Platform to Sense Nitrite Ions in Meat

Abstract

A sensor device based on doped-carbon quantum dots is proposed herein for detection of nitrite in meat products by fluorescence quenching. For the sensing platform, carbon quantum dots doped with boron and functionalized with nitrogen (B,N-Cdot) were synthesized with an excellent 44.3% quantum yield via a one-step hydrothermal route using citric acid, boric acid, and branched polyethylenimine as carbon, boron, and nitrogen sources, respectively. After investigation of their chemical structure and fluorescent properties, the B,N-Cdot at aqueous suspensions showed high selectivity for NO2 – in a linear range from 20 to 50 mmol L–1 under optimum conditions at pH 7.4 and a 340 nm excitation. Furthermore, the prepared B,N-Cdots successfully detected NO2 – in a real meat sample with recovery of 91.4–104% within the analyzed range. In this manner, a B,N-Cdot/PVA nanocomposite film with blue emission under excitation at 360 nm was prepared, and a first assay detection of NO2 – in meat products was tested using a smartphone application. The potential application of the newly developed sensing device containing a highly fluorescent probe should aid in the development of a rapid and inexpensive strategy for NO2 – detection.

Dual-Emission Carbon Dots for Fluorescent Sensing of Permanganate

“…In particular, UV−vis spectra show the π−π* transition of sp 2 -hybridized carbon at 233 nm, the n−π* transition related to carboxyl groups around 329 nm, and the π−π* transition of aromatic rings at 493 nm. 25,26 As illustrated in Fourier transform infrared (FTIR) characterization (Figure 1h), the stretching vibrations still preserved on the surface of the D-CDs, including the O−H/ N−H stretching at 3444 cm −1 , the asymmetric stretching (v as ) at 1640 cm −1 , the symmetric stretching (v s ) at 1408 cm −1 of carboxylate groups, and the C−O/C−N stretching between 1020 and 1245 cm −1 . 27−29 The chemical shifts of the D-CDs at 6.3 to 7.0 and 8.4 ppm correspond to that of hydroxyl and amino groups of fluorexon in 1 H nuclear magnetic resonance ( 1 H NMR) spectra, suggesting their similar conjugate structures.…”

“…Optimization of Determination Conditions. The test parameters may affect the surface charge of the D-CDs and the spacing between nanoparticles, 25 including media pH, incubation time, reaction temperature, and ionic strength. As shown in Figure S4, the FL ratio at pH 5−9 continues to rise and has yet to reach the plateau within 2 h, which is not conducive to rapid response.…”

Dual-signal detection of tannic acid in red wines based on the peroxidase activity of carbon dots

“…The overlap of N, 8 S, 11 F 12 and other elemental orbitals with C atomic orbitals may lead to changes in the electronic structure and optical properties of CDs. 13 Carneiro et al 14 hydrothermally synthesized B,N co-doped CDs, in which citric acid, boric acid, and branched polyethylenimine served as carbon, borate, and nitrate sources, respectively, and the synthesized CDs could be utilized to determine NO 2 − in meat, with a satisfactory quantum yield of 44.3%. Ding et al 15 used F-doping to synthesize CDs (F,N,S-CDs) with red fluorescence in the solid state.…”

Zein/MnO2 Nanosheet Composites Integrated with a Smartphone for Colorimetric Sensors for On-Site Detection of Adulterants in Milk

“…The transduction mechanism of a colorimetric sensor depends on the change in light absorption of a chemochromic material . Colorimetric sensors offer numerous advantages, including specificity, high sensitivity, cost effectiveness, ease of use, rapid analysis, straightforward operation, and clear visibility to the naked eye. , These sensors are typically composed of materials that undergo changes in their absorption band when exposed to the analyte of interest. In the past years, two-dimensional (2D) nanomaterials have attracted much attention due to their diverse properties, such as appropriate atomic-level thickness, high light absorption intensity, and large specific surface area, making them suitable for a wide range of applications, including colorimetric sensors. − …”