新型螢光碳量子點: 從天然物前驅物至高功能性之化學感測器

Newly Prepared Fluorescent Carbon Dots: From Effectual Natural Precursors to Functional Chemical Sensors

馬漢德(Muhammad Zulfajri)

指導教授 ： 黃俊嬴

高雄醫學大學/生命科學院/醫藥暨應用化學系博士班/博士(2021年)

摘要

None

關鍵字

None

並列摘要

The pollutant contaminations of heavy metals and organic dyes seriously endanger the environment and health of living things. So, the improvement of a favorably responded fluorescent (FL) sensor for pollutants is pivotal. In recent years, the preparation, properties, and use of carbon dots (CDs) gained great concern. Natural products are the effectual starting materials to prepare CDs with typical physicochemical properties. In this dissertation, a facile hydrothermal treatment was effectively performed to prepare eco-friendly CDs from cranberry beans (CB), Averrhoa carambola (AC) fruit, oyster mushroom (OM), and Volvariella volvacea mushroom (VV) as cheap and green natural carbon precursors. L-arginine (Arg) was used as a nitrogen source to enhance the FL properties of AC-NCDs. The preparation procedure was non-toxic, simple, and eco-friendly. The hydrothermal reaction times, hydrothermal temperatures, and starting material amounts were evaluated to determine the optimum synthetic conditions. All CDs’ characteristics were evaluated by several instruments including transmission electron microscopy (TEM), Raman spectroscopy, UV-light, UV-vis spectroscopy, zeta potential analyzer, Fourier transform infrared (FTIR) spectroscopy, FL spectroscopy, and FL lifetime spectroscopy. The CB-CDs, AC-NCDs, OM-CDs, and VV-CDs exhibited stable fluorescence properties with blue/cyan color and quantum yields of approximately 10.85%, 12.35%, 12.51%, and 11.50%, respectively. The CB-CDs, AC-NCDs, OM-CDs, and VV-CDs exhibited spherical forms with an average diameter of 3.96 nm, 6.67 nm, 6.54 nm, and 5.80 nm, respectively.
The CB-CDs emitted the wide FL emission ranging from 410 to 540 nm by altering the excitation. They were utilized to sense Fe3+ ions which can be achieved within 3 min with the excitation at 380 nm. The Fe3+ ions caused the reduction of CDs’ FL intensity stronger than numerous heavy metal ions. The CB-CDs could sense the Fe3+ ions with the linearity ranging from 30 to 600 μM and the limit of detection (LOD) of 9.55 μM. Meanwhile, the AC-NCDs showed the optimum emission center at 446 nm excited at 360 nm. The interaction between MO and AC-NCDs was reached with 3 min. The LOD of MO was quantified to be 0.30 μM with the linear relationship ranging from 1 to 25 μM. The pH values influenced the FL nature of the AC-NCDs/MO complex. The interaction and quenching mechanisms were affected by the π–π interaction, electrostatic interaction, inner filter effect (IFE), and energy transfer. The highest quenching efficiency was achieved at pH 5. OM-CDs’ FL nature of was obtained as excitation-dependent emission with the high emission center at 435 nm with 360 nm of excitation wavelength. The OM-CDs were utilized as a sensitive FL sensor toward nitroarenes (NAs) with low LODs and wide linear ranges. The NAs reduced OM-CDs’ FL emission based on the quenching mechanisms of photoinduced electron transfer (PET), Förster resonance energy transfer (FRET), and IFE. The UV-vis absorption spectra of o-NA and p-NA own a broader overlap than m-NA and p-NP with the FL excitation and emission spectra of OM-CDs, generating a more substantial quenching effect of o-NA and p-NA. The LODs were obtained as low as 0.78 µM (o-NA), 2.29 µM (m-NA), 0.50 µM (p-NA), and 1.56 µM (p-NP). Finally, the VV-CDs was utilized as an FL sensor for sensing Pb2+ and Fe3+ ions. The VV-CDs showed the emission based on the excitation character, with the highest FL emission center at 440 nm using 360 nm excitation wavelength. The VV-CDs were a facile and effective FL sensor for sensing Fe3+ and Pb2+ ions due to their FL quenching efficiency, and the certain complex chelate was formed between the Fe3+ or Pb2+ ions and specific functional groups onto the VV-CDs. The VV-CDs exhibited strong reaction with Pb2+ and Fe3+ ions, with the linear correlation ranging from 1 to 100 μM and LODs of 0.012 µM (Pb2+) and 0.016 µM (Fe3+). Besides, all CDs as the FL sensors were approved with real water samples, exhibiting remarkable recoveries of metal ions and dyes. Based on the superior findings, all synthesized CDs from some natural products can be used as the eco-friendly sensors for the future chemical sensing applications to protect the environment and living things. They can also be applied for numerous valuable applications, including colorimetric sensor, SERS sensor, catalyst, bioimaging, biosensor, drug delivery, energy storage device, and optoelectronic device.

並列關鍵字

Carbot Dots ； Fluorescent Sensor ； Metal Ions ； Organic Dyes ； Nitroarenes ； Hydrothermal ； Natural Product ； Green Precursor

參考文獻

[1] J. Ma, L. Bian, L. Zhao, X. Feng, L. Zhao, Z. Wang, Q. Pu, Dialysed caramel as an effective fluorophore for the simultaneous detection of three nitrophenols, Talanta. 197 (2019) 159–167.

[2] T.L. Rocha, N.C. Mestre, S.M.T. Sabóia-Morais, M.J. Bebianno, Environmental behaviour and ecotoxicity of quantum dots at various trophic levels: A review, Environ. Int. 98 (2017) 1–17.

[3] T. Otake, S. Aburada, H. Nishimura, S. ichi Nakamura, M. Ugawa, Y. Takagi, S. Akasaka, N. Ikegami, Toxicity of N-methyl-4-methoxynaphthalimide, a fluorescent whitening agent, Arch. Environ. Contam. Toxicol. 16 (1987) 119–127.

[4] H. Sun, F. Zhang, H. Wei, B. Yang, The effects of composition and surface chemistry on the toxicity of quantum dots, J. Mater. Chem. B. 1 (2013) 6485–6494.

[5] Y. Wang, Y. Zhu, S. Yu, C. Jiang, Fluorescent carbon dots: Rational synthesis, tunable optical properties and analytical applications, RSC Adv. 7 (2017) 40973–40989.