Aladesuyi Olanrewaju A, Oluwafemi Oluwatobi S
Department of Chemical Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, Johannesburg, South Africa.
Centre for Nanomaterials Science Research, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, Johannesburg, South Africa.
Heliyon. 2023 May 1;9(5):e15904. doi: 10.1016/j.heliyon.2023.e15904. eCollection 2023 May.
Herein, we reported the use of -doped green-emitting carbon quantum dots (-CQDs) as a fluorescent probe for determining of Fe ions in for the first time. The -CQDs were synthesised through an efficient, one-step, and safe hydrothermal technique using citric acid as the carbon source and glutamine as a novel nitrogen source. The temporal evolution of the optical properties was investigated by varying the synthetic conditions with respect to temperature (160 °C, 180 °C, 200 °C, 220 °C and 240 °C) and citric acid: glutamine precursor ratio (1:1, 1:1.5, l.2,1:3 and 1:4). The -CQDs was characterised using Fourier-Transform Infra-red Spectroscopy (FTIR) High-resolution transmission electron microscope (HRTEM), ultraviolet-visible spectroscopy (UV-vis) and X-Ray diffraction analysis (XRD) while its stability was evaluated in different media; NaCl, Roswell Park Memorial Institute (RPMI) and Phosphate Buffered Saline (PBS), and at different pHs. The -CQDs displayed green (525 nm) emission and were spherical with an average particle diameter of 3.41 ± 0.76 nm. The FTIR indicated carboxylic, amino, and hydroxyl functional groups. The as-synthesised -CQDs were stable in NaCl (up to 1 M), RPMI, and PBS without any significant change in its fluorescent intensity. The pH evaluation showed pHs 6 and 7 as the optimum pHs, while the fluorometric analysis showed selectivity towards Fe in the presence and absence of interfering ions. The detection limit of 1.05 μM was calculated, and the photoluminescence mechanism revealed static quenching. The -synthesised -CQDs was used as a fluorescent nanoprobe to determine the amount of Fe in (Potatoes) tubers. The result showed a high level of accuracy (92.13-96.20%) when compared with an established standard analytical procedure with excellent recoveries of 99.23-103.9%. We believe the -synthesised -CQDs can be utilised as a reliable and fast fluorescence nanoprobe for the determining of Fe ions.
在此，我们首次报道了使用氮掺杂的绿色发光碳量子点（N-CQDs）作为荧光探针来测定土豆中的铁离子。N-CQDs是通过一种高效、一步且安全的水热技术合成的，使用柠檬酸作为碳源，谷氨酰胺作为新型氮源。通过改变合成条件，包括温度（160℃、180℃、200℃、220℃和240℃）以及柠檬酸与谷氨酰胺前驱体比例（1:1、1:1.5、1:2、1:3和1:4），研究了光学性质的时间演变。使用傅里叶变换红外光谱（FTIR）、高分辨率透射电子显微镜（HRTEM）、紫外可见光谱（UV-vis）和X射线衍射分析（XRD）对N-CQDs进行了表征，同时在不同介质（NaCl、罗斯威尔公园纪念研究所（RPMI）培养基和磷酸盐缓冲盐水（PBS））以及不同pH值下评估了其稳定性。N-CQDs发出绿色（525nm）荧光，呈球形，平均粒径为3.41±0.76nm。FTIR表明存在羧基、氨基和羟基官能团。合成的N-CQDs在NaCl（高达1M）、RPMI和PBS中稳定，其荧光强度无任何显著变化。pH评估表明pH值6和7为最佳pH值，而荧光分析表明在存在和不存在干扰离子的情况下对铁离子具有选择性。计算出检测限为1.05μM，光致发光机制显示为静态猝灭。合成的N-CQDs用作荧光纳米探针来测定土豆块茎中的铁含量。与既定标准分析程序相比，结果显示出较高的准确度（92.13 - 96.20%），回收率极佳，为99.23 - 103.9%。我们相信合成的N-CQDs可作为一种可靠且快速的荧光纳米探针用于测定铁离子。
