ANALYTICAL SCIENCES
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2022
·Vol. 38
·期 10
·1305-1312
·
IF 1.967
Liu Piaotong,Hao Rusi,Sun Wenliang,Lin Ziyi,Jing Tianfeng,Yang Haizhen
A facile and efficient “bottle-around-ship” approach for preparing the ratiometric fluorescent probe has been developed by encapsulating the red-colored fluorescence CdTe quantum dots (QDs) and blue-colored fluorescence graphitic carbon nitride quantum dots (g-CNQDs) into the zeolitic imidazolate metal–organic frameworks (ZIF-8) in one step. At a single excitation of 360 nm, the obtained probe ZIF-8@g-CNQD/CdTe shows the dual-emission peaked at 450 and 633 nm, respectively. The red emission of CdTe QDs is selectively quenched by the Hg 2+ , whereas the blue fluorescence of g-CNQDs as an internal reference is insensitive, resulting in an apparent color transformation from pink to blue for special recognition of Hg 2+ . By this approach, the relative fluorescence intensity ratio ( F 633 / F 450 ) decreased linearly with increasing Hg 2+ concentration in the 0.2–3.5 μM range with a low limit of detection (LOD) of ~ 46 nM. Therefore, we demonstrate that this “bottle-around-ship” process provides a new strategy for the construction of ratiometric fluorescent Hg 2+ probes with good simplicity, high efficiency, and excellent stabilities. Moreover, the obtained Hg 2+ fluorescent probe shows good results in the detection of actual samples. Graphical abstract
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 11
·1-9
·
IF 5.479
Wu Huifang,Tong Changlun
A ratiometric fluorometric assay for silver(I) is described. The method makes use of a dually emitting quantum dot hybrid, which is composed of (a) blue-fluorescent silicon- and nitrogen-doped carbon quantum dots (CQDs), and (b) of red-emitting CdTe quantum dots (QDs) capped with N-acetyl-L-cysteine. The red-emitting CdTe QDs undergo strong and specific quenching by Ag(I), whereas the blue-emitting N,Si-CQDs are not quenched. The two kinds of QDs are mixed and used as a ratiometric fluorescent probe. A linear relationship is found between the log of intensities [(I 608 /I 441 ) 0 /(I 608 /I 441 )] and the concentration of Ag(I) in the range from 5.0–1000 nM, and the limit of detection (at S/ N = 3) is 1.7 nM. Possible interferents (including 17 general metal ions, 12 anions and fulvic acid) do not interfere with the determination. The assay was successfully used for the determination of Ag(I) in surface water and wastewater samples. The fluorescence quenching mechanism of the ratiometric assay system was also discussed in detailed.
Schematic representation of a ratiometric probe composed of silicon- and nitrogen-doped carbon quantum dots (N,Si-CQDs) and CdTe quantum dots capped by N-acetyl-L-cysteine (CdTe QDs). This dual-emission QDs hybrid was fabricated for ultrasensitive and highly selective detection of silver(I) in water samples.
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Analytical Methods
·
2018
·Vol. 10
·期 19
·2263-2271
·
IF 2.073
Yunmei Huang,Jidong Yang,Haiyan Yuan,Yuan Guo,Xiaoqing Zeng,Jiawei Cheng,Yuhui Zhang
D-Penicillamine (D-PA), as the dominant enantiomer, is usually used in many clinical drugs, but the other enantiomer, L-penicillamine (L-PA) is a toxic enantiomer. Therefore, it is of great significance to analyze and detect L-PA in biomedical or environmental samples. CdTe quantum dots (CdTe QDs) were modified by N-acetyl-L-cysteine (NALC) as novel fluorescent probes and were successfully utilized for the determination of L-penicillamine. The fluorescence of the CdTe QDs decreased significantly in the presence of cupric ions (Cu2+) due to the binding of Cu2+ to NALC on the surface of the CdTe QDs, but the addition of L-PA immediately resulted in efficient fluorescence recovery of the modulated CdTe QDs. The experimental results showed that the pH of the buffer solution and the concentration of Cu2+ affected the fluorescence intensity upon adding L-PA. Under the optimum conditions, the recovered fluorescence intensity was linearly proportional to the increasing L-PA concentration in the range of 2 × 10−7 to 4 × 10−6 mol L−1, with correlation coefficient R2 = 0.9980. So, a new, simple and rapid method for the determination of L-PA has been developed and its potential has been demonstrated in human serum samples and environmental samples with satisfactory results.
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JOURNAL OF LUMINESCENCE
·
2013
·
IF 2.144
Beibei Wang,Huan Shang,Cuiping Nie,Qi Wang,Meihu Ma,Zhaoxia Cai
A novel two-step controlled basic water phase method has been developed for synthesizing size-tunable and water-soluble CdTe/Cd(OH) 2 core/shell quantum dots with high quantum yield and good stability. The size of the prepared CdTe/Cd(OH) 2 core/shell quantum dots can be easily manipulated by varying the concentrations of NaOH solution step by step. The maximal emission wavelengths of the series CdTe/Cd(OH) 2 core/shell QDs were from 513 nm to 610 nm (emission colors tuned from green to red). The CdTe/Cd(OH) 2 core/shell quantum dots not only possess high quantum yield (up to 83%) but also exhibit excellent photostability (being stable after being stored for more than 2 months). The CdTe/Cd(OH) 2 core/shell quantum dots were characterized by transmission electron microscopy , high-resolution transmission electron microscopy, X-ray powder diffraction spectrometry , ultraviolet–visible spectrometry and fluorescence spectrometry. The water-soluble nature of the CdTe/Cd(OH) 2 core/shell quantum dots offers great potentiality for their chemical and biological applications. This method is easily controlled, low-cost and reproducible. So it is possible to extend this approach to the preparation of other size-tunable inorganic metal hydroxide capped core/shell quantum dots.
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INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2013
·Vol. 14
·期 5
·10397-10411
·
IF 2.464
Ning Gan,Jing Zhou,Ping Xiong,Tianhua Li,Shan Jiang,Yuting Cao,Qianli Jiang
The CdTe quantum dots (QDs), graphene nanocomposite (CdTe-G) and dextran–Fe3O4magnetic nanoparticles have been synthesized for developing an ultrasensitive electrochemiluminescence (ECL) immunoassay for Carcinoembryonic antigen 19-9 (CA 19-9) in serums. Firstly, the capture probes (CA 19-9 Ab1/Fe3O4) for enriching CA 19-9 were synthesized by immobilizing the CA 19-9’s first antibody (CA 19-9 Ab1) on magnetic nanoparticles (dextran-Fe3O4). Secondly, the signal probes (CA 19-9 Ab2/CdTe-G), which can emit an ECL signal, were formed by attaching the secondary CA 19-9 antibody (CA 19-9 Ab2) to the surface of the CdTe-G. Thirdly, the above two probes were used for conjugating with a serial of CA 19-9 concentrations. Graphene can immobilize dozens of CdTe QDs on their surface, which can emit stronger ECL intensity than CdTe QDs. Based on the amplified signal, ultrasensitive antigen detection can be realized. Under the optimal conditions, the ECL signal depended linearly on the logarithm of CA 19-9 concentration from 0.005 to 100 pg/mL, and the detection limit was 0.002 pg/mL. Finally, five samples of human serum were tested, and the results were compared with a time-resolved fluorescence assay (TRFA). The novel immunoassay provides a stable, specific and highly sensitive immunoassay protocol for tumor marker detection at very low levels, which can be applied in early diagnosis of tumor.Keywords:dextran-Fe3O4magnetic nanoparticles;sandwich immunoassay;graphene CdTe QD nanocomposite;carcinoembryonic antigen 19-9;electrochemiluminescence
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BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Xuehui Pang,Jihong Pan,Picheng Gao,Youying Wang,Liguo Wang,Bin Du,Qin Wei
It was reported that Proprotein convertase subtilisin/kexin type 6 (PCSK6) can promote the progression of rheumatoid arthritis to a higher aggressive status. In this work, a novel visible light induced photoelectrochemical (PEC) platform was designed to detect PCSK6 gene. ZnO@CdTe nanocable arrays/carboxylated g-C 3 N 4 used as the PEC signal generator . Hexagonal ZnO nanorods grew on ITO electrode firstly. CdTe were then electrodeposited on the ZnO nanorods surface to enhance the photogenerated h + /e − separation efficiency. Carboxylated g-C 3 N 4 was utilized to improve h + /e − separation efficiency and anchor the capture probes of PCSK6 gene by the covalent bonding effect. The 5′ and 3′ primers captured PCSK6 ssDNA by the specific recognition. The linear range was 10 pg/mL to 20.0 ng/mL with a detection limit of 2 pg/mL.
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Yao Fan,Lu Shen,Yaqi Liu,Ying Hu,Wanjun Long,Haiyan Fu,Yuanbin She
A ratiometric fluorescent probe based on N/S doped carbon dots (N/S-CQDs) and mercaptoacetic acid capped CdTe quantum dots (TGA-CdTe QDs) with sensitized and self-calibration functions was constructed to sensitively detect multiple tetracycline antibiotics (TCs). N/S-CQDs could attach stably to TGA-CdTe QDs and form a new composite ratiometric fluorescent probe that had a more than tenfold increase in sensitivity to TCs compared with each single QD. The probe could detect four common TCs as the color of the probe changed from bright red to dark red, and the limit of detection (LOD) was 1.47 × 10 −2 –1.78 × 10 −2 mg/L. Practical applications of the probe in food and urine were also verified with recovery rates of 95.21%-104.97%. Due to the abundant spectral fingerprints provided by both QDs, this novel probe could accurately recognize not only different single TCs but also mixed TC samples even in actual samples combined with chemometrics.
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Environmental Science-Nano
·
2022
·Vol. 9
·期 5
·1712-1723
·
IF 9.473
Mengqi Huang,Changlun Tong
A dual-emission ratiometric fluorescence probe for the simultaneous detection of tetracycline (TC) and Fe3+ in aqueous solution was fabricated based on a boron-doped carbon quantum dot (B-CQD)/CdTe–Eu3+ composite. Green-emitting CdTe QDs were modified by Eu3+; the fluorescence of CdTe QDs was quenched owing to the aggregation via Eu3+ and could be restored by the addition of TC. The fluorescence response of CdTe–Eu3+ is quite sensitive and selective to TC, which can be used as a turn on–off–on fluorescence probe for ultrasensitive and selective detection of TC. By introducing the blue-emitting B-CQDs with specific fluorescence response to Fe3+, a dual-emission ratiometric fluorescence probe of B-CQD/CdTe–Eu3+ was thus fabricated for the simultaneous detection of TC and Fe3+. At the excitation wavelength of 270 nm, the dual-emission fluorescence peaks are at 410 and 530 nm. A good linearity between the fluorescence intensity ratio (F530/F410 or F410/F530) and the concentrations of TC and Fe3+ in the range of 0.01–2.0 μM for TC and 0.1–15.0 μM for Fe3+ was shown. The limits of detection (LODs, 3σ/k) are ultrasensitive for TC (4.2 nM) and Fe3+ (53.0 nM). The dual-emission ratiometric fluorescent probe was successfully applied for the simultaneous determination of TC and Fe3+ in environmental water samples. The possible luminescence and fluorescence quenching/restoring mechanisms of the composite probe were also discussed in detail. This study can provide a new approach for fabricating a multifunctional fluorescent probe and a prospective application in environmental and food analysis.
研究领域:
分析化学
·
环境科学
·
材料科学
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2020
·Vol. 167
·期 14
·147520
·
IF 3.721
Xinyi Wang,Liubing Kong,Shuqi Zhou,Tao Liang,Hao Wan,Ping Wang
Photoluminescence (PL) sensors based on quantum dots (QDs) are difficult to achieve exact detection in sample waters. In this paper, polyvinyl alcohol (PVA) based CdTe/ZnS/CdS QDs and fluorescein isothiocyanate (FITC) fluorophores were used to build a ratiometric PL sensor. Combining with the homemade smartphone-based PL E-eye, the Cd2+ exact detection can be achieved. PVA was used to connect QDs and FITC fluorophores without unnecessary ligand exchange and purification. For QDs fluorophore, ethylenediaminetetraaceticacid (EDTA) was used on the surface to induce the specifically Cd2+ recognition site. For FITC fluorophore, the PL remains unchanged in this experiment. Thus, the ratio of two fluorophores can be used to provide a built-in correction. The PL changes with the increase of Cd2+ concentrations could be displayed as a visual color change on the smartphone. Further quantitative analysis could be carried out by the RGB value of the picture through the App in less than 1 min The ratio of R/G is linear to Cd2+ concentration in the range of 1–2000 μg l−1 with a low LOD of 0.057 μg l−1 (S/N). Compared with traditional analysis methods, the PL ratiometric method with PL E-eye is portable, rapid, visible and highly selective especially in discriminate Cd2+ from Zn2+.
研究领域:
环境科学
·
分析化学
·
纳米技术
·
光学传感
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