FOOD CHEMISTRY
·
2023
·
IF 8.8
Lidong Yang,Wei Hu,Fubin Pei,Zhiwei Liu,Jiang Wang,Zhaoyang Tong,Xihui Mu,Bin Du,Mingzhu Xia,Fengyun Wang,Bing Liu
Sensitive and rapid detection of pesticide residues in food is essential for human safety. A ratiometric imprinted fluorescence sensor N -CDs@Eu-MOF@MIP (BR@MIP) was constructed to sensitively detect malathion (Mal). Europium-based metal organic frameworks (Eu-MOF) were used as supporters to improve the sensitivity of the BR@MIP. N -doped carbon dots ( N -CDs) were used as fluorescent source to produce fluorescent signal. A linear relationship between the concentration of Mal and the fluorescence response of the sensor was found in the Mal concentration range of 1–10 μM with a limit of detection (LOD) of 0.05 μM. Furthermore, the sensor was successfully applied for the detection of Mal in lettuce, tap water, and soil samples, with recoveries in the range of 93.0 % − 99.3 %. Additionally, smartphone-based sensors were used to detect Mal in simulated real samples. Thus, the construction of ratiometric imprinted fluorescence sensor has provided a good strategy for the detection of Mal.
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Food Chemistry-X
·
2024
·
IF 6.5
Doudou Lei,Lingling Li,Pengyue Song,QingBin Xu,Lihua Huang,Xiao Ma,Lidong Zhou,Weijun Kong
Glyphosate (Gly) is a widely-used herbicide in food production, while, the residue of which due to the long-term and excessive overspray poses serious threats to public health. The development of reliable methods for its sensitive detection is of great urgency. In this study, a novel ratiometric fluorescent nanosensor by encapsulating N-doped carbon dots (N-CDs) and gold nanoclusters (AuNCs) in zeolitic imidazole framework-8 (ZIF-8) as the dual-emissive fluorescence probes at 410 and 650 nm, respectively, was constructed for Gly detection. Due to the adsorption property of ZIF-8, the N-CDs/AuNCs@ZIF-8 nanoprobes accumulated Cu 2+ to quench the red fluorescence of AuNCs, and the blue fluorescence of N-CDs was stable. While thiocholine, a product of acetylthiocholine, hydrolyzed by acetylcholinesterase could coordinate with Cu 2+ , resulting in significant fluorescence recovery of AuNCs. This phenomenon was utilized for the quantitation of Gly, due to its inhibitory effect on acetylcholinesterase activity. By calculating the fluorescence intensity ratio ( I 650 /I 410 ), Gly in real sample could be accurately determined in a concentration range of 2–100 ng/mL with a limit of detection of 1.92 ng/mL because of the anti-interference and the self-correction ability of the two fluorescence signals. The N-CDs/AuNCs@ZIF-8 nanoprobes-assisted ratiometric fluorescent nanosensor exhibited unique merits of rapid construction, simple operation, high specificity, and good accuracy for Gly in edible and medicinal malt samples with recoveries of 93.7–108.2 %. This study presents a multiple tool for the versatile sensing of trace pesticides in more food matrices, which can be extended to a full range of environmental and food safety applications.
研究领域:
分析化学
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食品安全
·
环境科学
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RSC Advances
·
2015
·Vol. 5
·期 116
·95744-95749
·
IF 3.84
Jiangling He,Bingfu Lei,Haoran Zhang,Mingtao Zheng,Hanwu Dong,Jianle Zhuang,Yong Xiao,Yingliang Liu
A facile and green approach for preparation of photoluminescent nitrogen-doped carbon dots (N-CDs) is reported, using cheap and extensively available cocoon silk as raw material. The use of H2O2 leads to the enhanced formation of N-CDs. The N-CDs have been synthesized in a short time (50 minutes), and have a high fluorescence quantum yield (24.0%). A small amount of H2O2 solution plays a vital role in shortening the reaction time, which is a brand new way to synthesize N-CDs with the help of H2O2, with both reactants and products being environmentally friendly. The prepared N-CDs are collected by removing the insoluble materials through simple filtration rather than dialysis. As far as we know, this is the first report of N-CDs being synthesized simply with the help of H2O2 solution. The prepared N-CDs solution is sensitive to pH changes, which means they have promise for application in the pH detection area.
研究领域:
材料科学
·
化学
·
环境科学
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RSC Advances
·
2018
·Vol. 8
·期 72
·41432-41438
·
IF 2.936
Min Chen,Wen Wu,Yuyuan Chen,Qingqing Pan,Yongzhong Chen,Zongfu Zheng,Yanjie Zheng,Liying Huang,Shaohuang Weng
Blue luminescent nitrogen-doped carbon nanodots (N-CDs) with pH-dependent properties were prepared from citric acid (CA), glutathione (GSH), and polyethylene polyamine (PEPA) using a two-step pyrolytic route. The N-CDs showed stable and strong emission bands at approximately 455 nm under 350 nm excitation. Moreover, the fluorescence of N-CDs can be gradually decreased by gradually increasing the pH value. A good linear relationship between the fluorescence intensity of N-CDs and the pH range of 3.0–9.0 was obtained. Thus, the response mechanism of N-CDs to pH was systematically investigated. N-CDs possessed –NH2, –COOH, and –CONH– as active functional groups, which allowed the variable protonation/deprotonation of N-CDs to regulate the fluorescence emission intensities under changed pH values. Furthermore, upon combining urease-catalyzed hydrolysis of urea with increased pH values, a simple but effective fluorescence assay for urea was developed. The analytical performance for urea detection was the linear range of 0 to 10 mM with a detection limit of 0.072 mM. Additionally, the fluorescent sensor based on N-CDs was successfully applied for pH detection in synovial fluid and urea determination in serum.
研究领域:
生物化学
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医学诊断
·
纳米材料科学
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CHEMICAL ENGINEERING SCIENCE
·
2025
·
IF 4.3
Meiling Xu,Linchun Nie,Jiawei Liao,Dejing Meng,Wenjing Liu,Haobo Yang,Ranhao Zhao,Qingxiang Zhou
A novel and visible ratiometric fluorescence sensor based on magnesium and nitrogen co-doped carbon dots (Mg, N-CDs) encapsulated in zeolitic imidazolate framework-8 (Mg, N-CDs@ZIF-8) was designed for effective detection of oxytetracycline (OTC), employing a “turn-off/turn-on” fluorescence sensing strategy. The blue-emission Mg, N-CDs@ZIF-8 was quenched owing to fluorescence resonance energy transfer by OTC, while the green fluorescence of OTC was significantly enhanced through the interaction of Mg 2+ and Zn 2+ with OTC, enhancing the visual tracking of OTC through a distinct blue-to-green color transition. This sensor displayed a wide linearity range (0.02 − 25 μg/mL), a low detection limit (14.2 ng/mL), and a fast response time (6 min). The validity of the sensor was successfully verified by detecting OTC in milk, honey, tap water, and lake water samples. Additionally, an expandable fluorescence sensor array was constructed for the discrimination of four tetracycline antibiotics (TCs) in real samples, indicating significant application in complex environmental samples.
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MICROCHEMICAL JOURNAL
·
2021
·
IF 4.821
Xu Chen,Jianliang Bai,Guojun Yuan,Lu Zhang,Lili Ren
Herein, a novel nitrogen-doped carbon dots (N-CDs) nanosensor for detecting Ag + and glutathione (GSH) has been designed. Interestingly, Ag + could significantly improve the fluorescence (FL) intensity of the N-CDs we prepared, which is different from most other metal ions with FL quenching effects on N-CDs. The sensing mechanism can be attributed to the oxidation characteristics of Ag + and the formation of silver nanoparticles (AgNPs). In the reaction, the N-CDs acted as the reducing agent and stabilizer. Under the optimal conditions, the N-CDs could detect Ag + with a nice linear relationship of R 2 = 0.992 and the limit of detection was 0.091 μM. Furthermore, the FL of N-CDs solutions could return to nearly original intensity after introducing glutathione (GSH), which allowed the N-CDs to be applied for GSH detection sensitively and selectively. In addition, the N-CDs were also successfully applied to cellular multicolor imaging of Hela cells. The results reported here pave the way for N-CDs-based fluorescent “off-on-off” sensor in environment, bioassay and bioimaging.
研究领域:
分析化学
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材料科学
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生物化学
·
生物医学工程
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2025
·
IF 4.6
Zhe Wang,Zixiao Wang,Jiamin Wang,Yu He,Junping Wang
A novel chiral electrochemical sensor was fabricated via the assembly of chiral nitrogen-doped carbon dots (N-CDs) with cobalt-based nanomaterials (Co@CoO) for the rapid discrimination and quantification of tyrosine enantiomers (L/D-Tyr). The sensor has a wide linear range of 1–120 µM and low detection limits of 0.64 µM for L-Tyr and 0.3 µM for D-Tyr. The synergistic interactions between N-CDs and Co@CoO amplify stereoselective recognition, yielding a chiral current ratio (ΔI = I L /I D ) of 1.65, which outperforms those of previously reported sensors. The chiral recognition mechanism was elucidated using cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, circular dichroism spectroscopy, Zeta potential analysis, and molecular dynamics simulations. The sensor demonstrates exceptional selectivity, stability, reproducibility, and reusability performance, and was successfully applied to the detection of L/D-Tyr in skim milk and yogurt. Notably, this sensor is the first to identify abnormally elevated D-Tyr levels in expired food products, suggesting a potential correlation between amino acid racemization and food quality deterioration. This study establishes a robust platform for chiral recognition in complex food matrices.
研究领域:
分析化学
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食品科学
·
纳米生物技术
·
电化学传感
·
手性识别
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TALANTA
·
2025
·
IF 6.1
Lijun Wang,Jiangchuan Tang,Shanshan Ren,Haixia Hu,Xiao Yang,Xianggui Chen
Although many colorimetric methods have been developed for on-site pesticide detection, most exhibit low sensitivity and limited resistance to interference. To address these issues, this study developed a novel dual-mode colorimetric-ratiometric fluorescence method for isocarbophos (ICP) detection using sulfur and nitrogen co-doped carbon nanodots (S, N-CDs) to inhibit catalytic Fe 3 O 4 @Cu-BTC nanozyme activity. The synthesized Fe 3 O 4 @Cu-BTC nanozymes with higher peroxidase-like activity were inhibited by S, N-CDs. The inhibitory mechanism was deeply investigated and was ascribed to (1) the restriction of the reaction between Fe 3 O 4 @Cu-BTC and hydrogen peroxide (H 2 O 2 ), which decreased the ·OH production, and (2) the ·OH scavenging ability of the S, N-CDs, forming the basis of the dual-mode method. The Fe 3 O 4 @Cu-BTC/Apt-complementary strand (CS)/S, N-CDs hybridization complexes demonstrated minimal to no peroxidase-like activity, preventing H 2 O 2 from oxidizing o -phenylenediamine (OPD) to produce yellow fluorescent 2,3-diaminophenazine (DAP). Meanwhile, the detection system demonstrated a low fluorescence intensity ratio (I 575 /I 465 ) at an excitation wavelength of 390 nm. However, the presence of ICP caused the CS/S, N-CDs to separate from the Fe 3 O 4 @Cu-BTC/Apt due to the high affinity between Apt and ICP. Then, the Fe 3 O 4 @Cu-BTC/Apt-ICP complexes recovered peroxidase-like activity, which promoted DAP production, accompanied by a pronounced fluorescence intensity ratio (I 575 /I 465 ). In optimum conditions, the detection limits (LODs) were 2.79 ng/mL (colorimetric) and 0.26 ng/mL (ratiometric fluorescence), respectively. The feasibility of the proposed method was verified via three spiked samples, yielding recovery rates of between 86.08 % and 112.64 %, indicating the significant potential for the highly sensitive, accurate on-site detection of ICP in actual samples.
研究领域:
分析化学
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环境科学
·
生物医学
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2020
·
IF 3.232
Kuanxia Ma,Lushan Liang,Xie Zhou,Weiguo Tan,Ou Hu,Zuanguang Chen
We develop a simple hydrothermal method to prepare a novel nitrogen-doped carbon dots (N-CDs) originated from green carbon source Liu-bao tea and ethylene diamine. The N-CDs emits strong and stable blue fluorescence (E m = 440 nm) under the excitation wavelength of 350 nm with a quantum yield of 35%. And it is used as an excellent fluorescent output for the sensitive and visual dual-mode determination of isoniazid. The fluorescence of N-CDs is “turned off” first by manganese dioxide (MnO 2 ) nanosheets due to inner filter effect, MnO 2 nanosheets can also oxidize TMB (3,3',5,5'- tetramethylbenzidine) to blue oxTMB. Isoniazid, however, can reduce MnO 2 nanosheets to Mn 2+ , turning on the fluorescence again. The color of the solution fades from blue to colorless because less TMB can be oxidized. Under the optimal conditions, the dual-mode method has a satisfying linear relationship ranging from 2.0 to 120.0 μM with a limit of detection of 0.7 μM (S/N = 3). And it has been applied successfully to colorimetric and fluorescent determination of isoniazid in tablets and clinical plasma samples, with recoveries ranging from 94.0% to 102.4%. The properties of N-CDs and MnO 2 nanosheets were thoroughly characterized using TEM, FT-IR, XPS, AFM and fluorescence spectrophotometer, the quenching mechanism was also discussed.
研究领域:
分析化学
·
药物分析
·
生物医学
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Chixuan Yao,Yaozhong Hu,Qisijing Liu,Jing-Min Liu,Xuemeng Ji,Huan Lv,Shuo Wang
To improve the performance of peanut allergen Ara h 3 detection, depending on boron and nitrogen carbon dots (B/ N -CDs), a nanobody (Nb) mediated dual-mode immunoassay was established, which combines the dominance of colorimetry with ratiometric fluorescence techniques. With the catalysis of Horseradish peroxidase (HRP), the oxidization of o-phenylenediamine (o-PD) in the presence of H 2 O 2 , leading to the production of yellow 2,3-diaminophenolazine (DAP) with an absorption peak at 431 nm. Owing to inner filter effect (IFE), DAP quenched the fluorescence of B/ N -CDs at 426 nm, and it emerged a new emission peak at 549 nm. The fluorescence intensity ratio and absorption intensity can be utilized for quantitative analysis of Ara h 3 concentration. Under optimal conditions, the detection limits were 6.61 and 9.79 ng·mL −1 , respectively. The dual-mode immunoassay was assessed containing specificity, stability, reproducibility, and practicability. This method paved the way for sensitive detection of Ara h 3 without background Interference.
研究领域:
过敏学
·
分析化学
·
纳米技术
·
食品安全
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MICROCHIMICA ACTA
·
2026
·Vol. 193
·期 1
·60
·
IF 5.3
Yang Yu Zhu,Li Gui Yong,Zhang Pu,Cui Linyun,Liu Huan Li,Chen Shi,Dai Xin
In this study, N-CDs were combined with Eu 3+ to construct a ratiometric fluorescence sensor (N-CDs@Eu 3+ ) for the determination of tetracycline (TC). The nitrogen-doped carbon dots (N-CDs) with good water solubility, excellent fluorescence performance, and high stability successfully prepared by using the leaves of Mahonia fortunei leaf as the carbon source and ethylenediamine as the nitrogen source through a one-step thermal solvent method. In the presence of TC, the fluorescence intensity of N-CDs at 510 nm was quenched due to fluorescence resonance energy transfer (FRET), while the fluorescence intensity of Eu 3+ at 616 nm was significantly enhanced through the antenna effect (AE). This ratiometric fluorescence sensor enables rapid, sensitive and highly selective detection of TC, with a detection limit as low as 7.5 nM. Moreover, a distinct color change from green to red can be observed under a 365 nm UV lamp. With the assistance of a smartphone sensing platform, visual semi-quantitative monitoring of TC was achieved. This method was successfully applied to the detection of TC in milk, pork, and honey, with recoveries ranging from 90.6% to 105.0%. This research demonstrates that this sensor holds potential application value in the field of real-time visualization detection and semi-quantitative determination of TC in biomedical and food safety sensing fields. Graphical abstract
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TALANTA
·
2024
·
IF 5.6
Linchun Nie,Liushan Jiang,Shuangying Li,Denghao Song,Guangyu Dong,Lutong Bu,Chunmao Chen,Qingxiang Zhou
Present work reported a novel nanozyme g-C 3 N 4 @Cu, N-CDs with excellent peroxidase-like activity obtained by loading Cu and N co-doped carbon dots on g-C 3 N 4 (graphitic carbon nitride). g-C 3 N 4 @Cu, N-CDs can catalyze H 2 O 2 to generate hydroxyl radical •OH, which oxidizes o -phenylenediamine to 2,3-diaminophenazine, which emits orange fluorescence under ultraviolet light irradiation. The experimental results confirmed that 1,4-benzenedithiol (BDT) could inhibit the peroxidase-like activity of g-C 3 N 4 @Cu, N-CDs. Based the principle above, a colorimetric-fluorescence dual-mode sensor for rapidly sensing of BDT was creatively constructed with assisting of a smartphone. The sensor showed excellent linearity over ranges of 0.75–132 μM and 0.33–60.0 μM with detection limits of 0.32 μM and 0.25 μM for colorimetric and fluorescence detection, respectively. Moreover, a smartphone-assisted colorimetric array sensor was constructed to distinguish six sulfur-containing compounds according to the difference in the degree of inhibition of nanozyme activity by different sulfur-containing compounds. The array sensor could distinguish sulfur-containing compounds at low concentration as low as 0.4 μM. The results validated that the designed sensor was a convenient and fast platform, which could be utilized as a reliably portable tool for the efficient and accurate detection of BDT and the discrimination of multiple sulfur compounds in real water samples.
研究领域:
分析化学
·
生物传感
·
材料科学
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