Fluorescent Nitrogen-doped Carbon Dots Research Articles

Highly fluorescent nitrogen doped carbon dots as analytical probe for sensitive detection of curcumin through smartphone integrated 3D-printed platform: A new horizon in food safety

COVID-19 pandemic has significantly influenced the dietary habits of humans, emphasizing the incorporation of natural ingredients to enhance immunity towards viral and bacterial infections. Curcumin (Cur), a widely used traditional medicine in various Asian countries and a natural coloring agent, has gained popularity, leading to surge in its usage specially in post COVID-19 era. This surge has led to increased scrutiny of the potential side effects of excessive Cur use, with recent reports suggesting it may result in inactivation of DNA and reduce adenosine triphosphate levels, leading to health risks. In this work, we synthesized highly fluorescent nitrogen-doped carbon dots with a photoluminescence quantum yield of 72.9 % for the sensitive and selective detection of Cur. The developed fluorescent probe exhibits excellent sensory response towards Cur within a concentration range of 0.081–51.45 µM, achieving an ultra-low detection limit of 15.91 nM. The sensor was successfully tested on real food samples like ginger powder, turmeric powder, and curry powder, demonstrating good recovery rates. To assess the practicality of the sensor system, we developed a 3D-printed smartphone-integrated device platform for curcumin detection through fluorescence image analysis. This developed platform exhibited promising results, achieving a limit of detection (LoD) of 132.28 nM across a curcumin concentration range of 0.13–54.00 µM. This device platform holds significant potential for the development of efficient sensors for real-time detection of Cur in food samples.

In Situ Growth of Nitrogen-Doped Fluorescent Carbon Dots on Sisal Fibers: Investigating Their Selective and Enhanced Adsorption Capabilities for Methyl Blue Dye.

Preparing a biomass adsorbent material with high-absorption performance but low cost plays a vital role in wastewater treatment. In this study, a novel nitrogen-doped sisal fiber-based carbon dots (SF-N-CDs) composite was prepared by directly growing carbon dots (CDs) on sisal fiber (SF) using a microwave method with polyethyleneimine (PEI) as a raw material. The prepared SF-N-CDs were characterized using FTIR, XRD, Contact angle(CA), TGA, XPS, and SEM. The results revealed that the CDs were successfully grown on SF. The adsorption properties of SF-N-CDs were significantly enhanced when they adsorbed methyl blue (MeB) dye. Specifically, the adsorption of MeB by SF-N-CDs was up to 619.7mg/g, which was about 2.6 times higher than that of raw SF. This implied that the introduction of CDs increases the adsorption site, thus enhancing the adsorption capacity. Analysis on kinetics and thermodynamics of MeB adsorption by SF-N-CDs revealed that the adsorption process followed the Langmuir isotherm model and were consistent with both kinetic models. It signifies that the adsorption involves both physical and chemical adsorption processes. Further, the SF-N-CDs maintained a removal rate of 70.9% after six adsorption-regeneration cycles, demonstrating good regeneration performance. Moreover, the SF-N-CDs could selectively separate MeB from a mixture of rhodamine B and saffron T. Consequently, the findings of this study suggest that SF-N-CDs are promising adsorbents for anionic dyes.

Construction of Cyan Blue Fluorescence Probe based on Nitrogen-Doped Carbon Dots for Detecting Nitrite Ion in Ham Sausage.

Nitrite ion is one of the materials widely used in human life, and the accurate, sensitive and stable detection of nitrite ions is of great significance to people's healthy life. In this study, nitrogen-doped fluorescent carbon dots (N-CDs) for detecting nitrite salt solutions were prepared using citric acid monohydrate and Chrysoidin as precursors through a one-pot hydrothermal method. Under the condition of pH = 3, a noticeable quenching phenomenon occurred in the carbon dot solution with the increase in nitrite ion concentration. This quenching effect might be attributed to the diazonium effect. N-CDs have been successfully used as fluorescence probes for NO2- detection. NO2- can effectively quench the fluorescence intensity of N-CDs, providing a linear response to fluorescence quenching efficiency with respect to NO2- concentration within the range of 0-10µM and 10-30µM, and a detection limit of 52nM, showing high sensitivity. In addition, the probe was applied to the determination of NO2- in ham sausage samples with a detection limit of 0.67µM and recoveries in the range of 99.5-102.3%, the fluorescent probe showed satisfactory reliability.

Mesoporous silica-encapsulated nitrogen-doped fluorescent carbon dots modified polydopamine composites for monitoring non-steroidal anti-inflammatory drugs

A one-pot hydrothermal process incorporated nitrogen-doped fluorescent carbon dots (N-FCDs) into the pores of mesoporous silica (m-SiO2). Under weakly alkaline conditions, the m-SiO2/N-FCDs were further functionalized with dopamine to develop m-SiO2/N-FCDs modified polydopamine (m-SiO2/N-FCDs/PDA). The m-SiO2/N-FCDs/PDA exhibited emission at a wavelength of 520 nm (λexc. = 440 nm) and demonstrated excellent quenching efficiency in the presence of NSAIDs (aspirin, diclofenac, ketoprofen, naproxen, and ibuprofen) with a detection limit of 0.045 – 1.43 nM. Furthermore, the m-SiO2/N-FCDs/PDA was utilized to detect NSAIDs in tap and river water and pharmaceutical commercial tablets showing high recoveries of 90.96–100.41 % with RSD < 4.

Construction of nitrogen-doped carbon dots-based fluorescence probe for rapid, efficient and sensitive detection of chlortetracycline

Antibiotics are widely used in clinical medicine due to their excellent antibacterial abilities. As typical emerging pollutants, their misuse can lead to excess antibiotics entering the environment, causing antimicrobial resistance and leading to serious health problems via food chain. Herein, a nano-fluorescent probe based on nitrogen-doped carbon dots (N-CDs) was constructed for the sensitive detection of chlortetracycline (CTC). N-CDs with stable fluorescence were synthesized by hydrothermal method using alizarin red and melamine as raw materials. The N-CDs exhibited significant independence to excitation wavelength. The fluorescence of N-CDs was significantly quenched by CTC ascribing to the fluorescence resonance energy transfer mechanism. The concentration of N-CDs, solution pH and incubation time were optimized to obtain the optimal detection parameters. Under optimal conditions, CTC exhibited excellent linearity over the range of 20–1200 μg/L, and the detection limit was 8.74 μg/L. The method was validated with actual water samples and achieved satisfied spiked recoveries of 97.6–102.6%. Therefore, the proposed method has significant application value in the detection of CTC in waters.

A dual-mode sensing system for xanthine oxidase detection based on nitrogen-doped carbon dots and iron-cobalt oxide nanosheets

As one of the existing forms of xanthine oxidoreductase, xanthine oxidase (XOD) exists in many human tissues, and the overactivity of XOD will result in some serious illnesses such as gout and diabetes. Herein, a novel dual-signal sensing system for XOD activity determination was proposed based on fluorescent nitrogen-doped carbon dots (N-CDs) and iron-cobalt oxide nanosheets (FeCo-ONSs). XOD has the ability to oxidise xanthine to uric acid while also producing H2O2. As a sort of peroxidase-like enzyme, FeCo-ONSs can catalyze H2O2 to produce reactive oxygen species (ROS). And N, N-Diethyl-p-phenylenediamine sulfate salt (DPD) was oxidized to DPDox that serves as a chromogenic substrate in the presence of ROS, causing the colorless solution to turn pink. DPDox exhibits two characteristic absorption peaks at 551 nm and 512 nm and it can also efficiently quench the fluorescence emission of N-CDs at 500 nm. Therefore, the fluorometric and colorimetric dual-channel sensing platform was established to assay XOD with the lower LOD of 0.00522 mU/mL and 0.0177 mU/mL, respectively. Additionally, the dual-output strategy was found to be applicable to the quantitative analysis of XOD in serum samples with good reliability and selectivity.

Hydrothermally synthesized fluorescent nitrogen-doped carbon dots for catalytic efficiency and anti-counterfeiting application

Here, Tylophora indica plant extract was utilized to create nitrogen-doped carbon dots by hydrothermal method. The synthesized NDCDs was employed to anti-counterfeiting and enhancing the catalytic activity of Malachite Green dye. The ultraviolet–visible spectroscopy and FT-IR measurements was used to analyze the optical properties and the development of NDCDs as well as the source of Tylophora indica. Using HR-TEM, XRD, and XPS, the structure and elemental contents of the produced NDCDs was investigated. The HRTEM images showed that the NDCDs had a d-spacing of 0.37 nm and an average particle size of 4.3 ± 1 nm. After being subjected to UV light at 365 nm, the produced NDCDs began to glow blue, with a quantum yield (QY) of 16.1 %. The ID and IG ratio values for NDCDs were found to be 0.86. With rate constant values calculated at 0.1830 min−1, respectively, the synthesized NDCDs were found to be a viable catalyst for the Malachite Green (MG) dye reduction process utilizing freshly prepared NaBH4. In addition, the NDCDs solution is used as fluorescent ink. The printed patterns retain their anti-counterfeiting properties even after being heated and stored in an environment for an extended period, indicating the NDCDs stability for prospective anti-counterfeiting applications.

Nitrogen-doped carbon dots for 3D printed smartphone-assisted cascade visual detection of morin and aluminium ion, solid fluorescence ink

With the growing emphasis on health management, individuals increasingly focus on monitoring drug molecular residues and harmful ions. Motivated by the concepts of the intelligent system and quantitative detection, we develop a smartphone-assisted cascade visual sensing device based on nitrogen-doped carbon dots (N-CDs) for in-site quantitative detection of morin and aluminium ion (Al3+). Initially, citric acid and o-phenylenediamine are identified as precursors for N-CDs synthesis via the microwave-assisted hydrothermal treatment. Subsequently, systematic studies reveal that the fluorescence of N-CDs is quenched upon the introduction of morin because of the inner filter effect (IFE). Conversely, the fluorescence recovery phenomenon occurs after the cascade addition of Al3+ since the morin binds with Al3+, resulting in the inhibition of IFE. Simultaneously, the fluorescence recovery of N-CDs enhances the cyan fluorescence emission of morin/Al3+. Based on the fluorescence quenching and recovery behavior, morin and Al3+ can be detected in the ranges of 0.070–50 μM and 0.124–40 μM with low detection limits of 0.070 μM and 0.124 μM, respectively. Furtherly, a smartphone-assisted cascade visual sensing device is designed for in-site quantitative detection of morin and Al3+. Moreover, based on the strong fluorescence and concentration-dependent emission behavior of N-CDs, the multi-color fluorescent ink is developed successfully. This work not only offers an excellent solution for simultaneous detection of morin and Al3+ but also shows numerous opportunities for solid lighting, information encryption and flexible optics.

Microwave-Assisted Grafting of Coal onto Nitrogen-Doped Carbon Dots with a High Quantum Yield and Enhanced Photoluminescence Properties.

The fluorescent nitrogen-doped carbon dots (N-CDs) were synthesized via a facile one-pot solvothermal process using coal (Jin 15 Anthracite and Shaerhu lignite) as raw materials and dimethyl formamide (DMF) as the solvent, employing a microwave pyrolysis method. This approach demonstrates remarkable efficacy in the development of nitrogen-doped carbon dots (N-CDs) with a high quantum yield (QY). The N-CDs prepared have strong photoluminescence properties. Moreover, the obtained N-CDs emit blue PL and are easily dispersed in polymethyl methacrylate (PMMA), preserving the inherent advantages of N-CDs and the PMMA matrix. The JN-CDs exhibit a high quantum yield (QY) of 49.5% and a production yield of 25.7%, respectively. In contrast, the SN-CDs demonstrate a quantum yield of 40% and a production yield of 35.1%. It is worth noting that the production yield and quantum yield of coal-based carbon dots are inversely related indices. The lower metamorphic degree of subbituminous coal favors an enhanced product yield, while the higher metamorphic degree of anthracite promotes an improved quantum yield in the product, which may be attributed to the presence of amorphous carbon within it. Consequently, we propose and discuss potential mechanisms underlying N-CD formation.

Synthesis of nitrogen-doped fluorescent carbon dots for determination of nickel ions and morin from aqueous solution simultaneously

Considering the significant impact of heavy metals on environment and food safety inspection in trace determination, the orange photoluminescent carbon dots (O-CDs) was innovative designed by promoting the co-hydrothermal reaction of polyethyleneimine and resazurin. The produced O-CDs exhibit exceptional optical performance, advantageous water solubility and outstanding photostability. It is worth emphasizing that the proposed O-CDs has significant advantages in constructing sequential sensing platform for sensitive determination of Ni2+ and morin. Simultaneous taking Ni2+ for analytes and fluorescence quenching agents on the O-CDs sensing platforms, a good linear relationship can be received in the range of 5–50 μM with satisfactory sensitivity. Subsequently, morin can effectively promote the fluorescence recovery of O-CDs@Ni2+ on account of stronger binding force between morin and Ni2+. Based on the above results, effective recovery of 97.26 %-100.90 % and 98.24 %-101.99 % is observed towards nickel ion and morin in real food samples. These findings provide an original strategy for the construction of long-wavelength emission carbon dots, which provides a pathway for the determination of typical pollutants based on efficient and robust nanosensors in the field of food safety.

On-Off-On Fluorometric Detection of Hg(II) and L-Cysteine Using Red Emissive Nitrogen-Doped Carbon Dots for Environmental and Clinical Sample Analysis.

This research introduces a novel fluorescence sensor 'on-off-on' employing nitrogen-doped carbon dots (N-CDs) with an 'on-off-on' mechanism for the selective and sensitive detection of Hg(II) and L-cysteine (L-Cys). N-CDs was synthesized using citric acid as the carbon precursor and urea as the nitrogen source in dimethylformamide (DMF) solvent, resulting in red emissive characteristics under UV light. Comprehensive spectroscopic analyses, including UV-Vis, fluorescence, FT-IR, XRD, XPS, Raman, and Zeta potential techniques, validated the structural and optical characteristics of the synthesized N-CDs. The maximum excitation and emission of N-CDs were observed at 548 and 622nm, respectively. The quantum yield of N-CDs was calculated to be 16.1%. The fluorescence of N-CDs effectively quenches upon the addition of Hg(II) due to the strong coordination between Hg(II) and the surface functionalities of N-CDs. Conversely, upon the subsequent addition of L-Cys, the fluorescence of N-CDs was restored. This restoration can be attributed to the stronger affinity of the -SH group in L-Cys towards Hg(II) relative to the surface functionalities of N-CDs. This dual-mode response enabled the detection of Hg(II) and L-Cys with impressive detection limits of 15.1 nM and 8.0 nM, respectively. This sensor methodology effectively detects Hg(II) in lake water samples and L-Cys levels in human urine, with a recovery range between 99 and 101%. Furthermore, the N-CDs demonstrated excellent stability, high sensitivity, and selectivity, making them a promising fluorescence on-off-on probe for both environmental monitoring of Hg(II) and clinical diagnostics of L-Cys.

A Dual-Mode Detection Sensor Based on Nitrogen-Doped Carbon Dots for Visual Detection of Fe(III) and Ascorbic Acid via a Smartphone.

Accurately and promptly detecting Fe3+ and ascorbic acid (AA) is a crucial objective. In this study, nitrogen-doped carbon dots (N-CDs) were synthesized using a one-step hydrothermal synthesis method with 6,9-diamino-2-ethoxyacridine lactate as the precursor. The introduction of Fe3+ and AA resulted in both fluorescence (FL) quenching and enhancement of the synthesized N-CDs. The fluorescent response of the N-CDs probe to Fe3+ was observed in the concentration range of 5-20 µM and 25-50 µM, with a limit of detection (LOD) of 290 nM. Remarkably, the fluorescence of the N-CDs was recovered upon the addition of AA to the N-CDs-Fe3+ system. Using the "off-on" fluorescent N-CDs probe, a linear range of 40-90 µM was achieved with an LOD of 0.69 µM. Additionally, the feasibility of employing a smartphone equipped with an RGB Color Picker was demonstrated for the analysis of Fe3+ and AA concentrations, providing a novel visual detection method. Furthermore, the application of N-CDs in solution demonstrated considerable potential for visually detecting Fe3+ and AA. The proposed dual-mode detection sensor was found to be simple, efficient, and stable, enabling the successful determination of Fe3+ and AA in practical samples with satisfactory results.

Facile synthesis of nitrogen-doped carbon dots for ultrasensitive detection of anticancer drug gefitinib based on IFE

Gefitinib, a highly significant antitumor drug, is now commonly employed in clinical settings as a first-line treatment for patients with advanced or metastatic non-small cell lung cancer, colon cancer, and breast cancer. Herein, a convenient, rapid, and accurate fluorescence method based on nitrogen-doped carbon dots (NCDs) was designed for ultrasensitive detection of gefitinib. The NCDs were easily synthesized through one-pot hydrothermal process using p-phenylenediamine and D-glutamic acid as the precursors. The sensing strategy relied on the fluorescence of NCDs at 345 nm, which was selectively reduced by gefitinib based on the inner filter effect (IFE). With a broad linear range of 0.025–30 μg/mL and a low limit of detection of 5.5 ng/mL, the probe was successfully applied to the detection of gefitinib in human serum samples, demonstrating strong practicality, affordability, and high accuracy. The proposed sensor is simple in design, fast in detection and cost-effective, and exhibits promising application in drug real-time analysis.

Preparation of Microcrystalline Cellulose-Derived Carbon Dots as a Sensor for Fe3+ Detection

In this article, nitrogen-doped carbon dots (N-CDs) were prepared by a hydrothermal method using microcrystalline cellulose as the carbon source and polyethylenimine as the nitrogen source. The ratio of microcrystalline cellulose to polyethylenimine added exerted a great influence on the fluorescence quantum yield of N-CDs. The fluorescence intensity of N-CDs 2 was significantly affected by the solvent type and pH value, but not influenced by the time of irradiation with the UV lamp. Intriguingly, N-CDs 2 could be applied to temperature sensing (30~70 °C). With the addition of Fe3+ (20 ppm), the fluorescence of N-CDs 2 was greatly quenched, and the quenching rate reached 82.84%. The fluorescence intensity of N-CDs 2 showed a good linear relationship (R2 = 0.995) with Fe3+ concentrations (0~14 ppm), and they achieved a limit of detection of 0.21 ppm. In addition, N-CDs 2 could also effectively detect Fe3+ in real water samples, showing a good recovery rate (98.25%~102.75%) and low relative standard deviation (less than 3%). According to the fluorescence lifetime data, the fluorescence quenching of N-CDs by Fe3+ might be a static process.

PH-responsive green fluorescent nitrogen-doped carbon dots for visualization of intracellular pH with intuitive color changes

Designing pH-sensitive nanoprobes for visualization of intracellular pH with intuitive color change is of high significance for better understanding the pathogenesis of diseases. However, most of the reported intracellular pH imaging strategies are the single intensity-based strategies, which are susceptible to interferences from background effects. In this work, pH-responsive green fluorescent nitrogen-doped carbon dots were synthesized for visualization of intracellular pH with intuitive color change. The as-prepared green fluorescent N-CDs exhibited obvious red fluorescence when the pH value was less than 7, while only the green fluorescence intensity changed under neutral or alkaline conditions, which can be visually observed by the naked eye. In addition, the mechanism of the green fluorescence of the N-CDs was systematically investigated by density-functional theory (DFT) theoretical calculation together with X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared spectrophotometer (FT-IR), as well as the mechanism of the response of N-CDs to pH was systematically investigated by absorption spectrum and transmission electron microscope (TEM). Furthermore, the as-prepared green fluorescent N-CDs were used to visualize intracellular pH with intuitive color changes, demonstrating its promising potential in visual bio-imaging.

Nitrogen-Doped Carbon Dots Encapsulated a Polyoxomolybdate-Based Coordination Polymer as a Sensitive Platform for Trace Tetracycline Determination in Water.

The requirement of simple, efficient and accurate detection of tetracycline (TC) in water environments poses new challenges for sensing platform development. Here, we report a simple method for TC sensing via fluorescence detection based on metal-organic coordination polymers (MOCPs, (4-Hap)4(Mo8O26)) coated with nitrogen-doped carbon dots (NCDs). These NCDs@(4-Hap)4(Mo8O26) composites showed excellent luminescence features of NCDs with stable bright-blue emission under UV light. The results of the sensing experiment showed that the fluorescence of NCDs@(4-Hap)4(Mo8O26) can be quenched by TC (166 µM) with 94.1% quenching efficiency via the inner filter effect (IFE) in a short time (10 s), with a detection limit (LOD) of 33.9 nM in a linear range of 8-107 µM. More significantly, NCDs@(4-Hap)4(Mo8O26) showed a high selectivity for TC sensing in the presence of anions and metal cations commonly found in water environments and can be reused in at least six cycles after washing with alcohol. The potential practicality of NCDs@(4-Hap)4(Mo8O26) was verified by sensing TC in real water samples with the standard addition method, and satisfactory recoveries from 91.95% to 104.72% were obtained.

Zero Thermal Quenching Phenomenon of Green Emitting Carbon Dots with High Biocompatibility and Stable Multicolor Biological Imaging in a Hot Environment.

Carbon dots are emerging fluorescent nanomaterials with unique physical and chemical properties and a wide range of applications. Herein, we have designed and successfully synthesized thermally stable green emissive nitrogen-doped carbon dots (NCDs) with a photoluminescent quantum yield of 11.32% through facile solvent-free carbonization. NCDs demonstrated zero thermal quenching upon various temperatures modulating from 20 to 80 °C. The green emissive NCDs perform very stably even after heating them at 80 °C for 1 h. The thermal stability mechanism demonstrates that C═O and C═N functional groups control the particle aggregation and protect the fluorescent hub from photo-oxidation and thermal oxidation. Highly biocompatible CDs exhibit bright, stable, and multicolor emissions in T-ca cells under hot circumstances (25-45 °C). Additionally, NCDs offer long-term stability in the biosystem, as evidenced by the fact that the cell retains its brightness about 70% after prolonging the incubation time to 8 days. Furthermore, the fluorescent NCDs are utilized as in vivo imaging agents in the hot environment as they display bright and thermally stable imaging (27-45 °C) under 488 nm excitation. The results confirmed that the produced thermally stable NCDs could be used in biology and related medical fields that require hot environment imaging.

A Dual-mode Ratiometric Fluorometric and Colorimetric Platform Based on Nitrogen-doped Carbon Dots and o-phenylenediamine for the Detection of Nitrite.

In this study, a dual-mode ratiometric fluorometric and colorimetric platform for the determination of nitrite in pickles was proposed by exquisitely employing the fact that non-fluorescent o-Phenylenediamine (OPD) was oxidized by nitrite under acidic conditions to form fluorescent 2,3-diaminophenazine (DAP) (Em = 575), which meanwhile quench the fluorescent nitrogen-doped carbon dots (N-CDs) at 455nm, the ratio of fluorescence intensity of DAP to N-CDs (F575/F455) changed with the increase of nitrite accompanied by visible color changes. Thus, nitrite can be quantitatively detected within a wide linear range (10-500 µM) with a low detection limit of 0.45 µM due to the high quantum yield of 39.7% of N-CDs. In addition, the colour of the N-CDs/OPD system changed from transparent to yellow when the nitrite was introduced, enabling colorimetric and on-site visual detection. The detection limit of the colorimetric method was 3.03 µM with a linear range of 10-500 µM. The proposed ratiometric fluorometric method has pleasant selectivity and good immunity to interference.

Synthesis of Temperature Sensing Nitrogen-Doped Carbon Dots and Their Application in Fluorescent Ink.

With the discovery of research, many properties of carbon dots are getting better and better. People have taken advantage of this and utilized them interspersed in various fields. In the present study, water-soluble nitrogen-doped carbon dots (N-CDs) with excellent optical and fluorescence thermal properties were prepared by the hydrothermal method using 4-dimethylaminopyridine and N,N'-methylenebisacrylamide as precursors. Co2+ has a selective bursting effect on the fluorescence of N-CDs. The fluorescence of N-CDs is selectively burst by Co2+, and the high sensitivity is good in the range of 0-12 μM with a detection limit of 74 nM. In addition, the good temperature response (reversible and recoverable fluorescence in the temperature range of 20~90 °C) and excellent optical properties of the N-CDs also make them new potentials in the field of fluorescent inks and temperature sensing.

Development of a novel fluorescent aptasensor based on the interaction between hexagonal β-Co(OH)2 nanoplates and nitrogen-doped carbon dots for ultrasensitive detection of patulin

There is an urgent need to develop an economical and convenient method for the ultrasensitive detection of patulin (PAT), a mycotoxin that can potentially harm human health when it is found in fruits and their derivatives. In this study, we have developed a novel fluorescent aptasensor that utilizes nitrogen-doped carbon dots (N-CDs) as the fluorescent donor and hexagonal β-Co(OH)2 nanoplates as the fluorescent acceptor. N-CDs were synthesized through the hydrothermal method, resulting in spherical particles with a diameter of 7.6 nm. These nanoparticles exhibited excellent water solubility and displayed a vibrant blue emission at 448 nm when excited at 360 nm. Cobalt hydroxide nanoplates with a beta crystal structure [β-Co(OH)2] were synthesized using a simple co-precipitation method, exhibiting hexagonal plate-like shapes with uniform lateral sizes of 4–5 μm. The fluorescence of N-CDs can be efficiently quenched by hexagonal β-Co(OH)2 nanoplates through Förster resonance energy transfer mechanism. The maximum quenching-recovery capability can be achieved when the concentrations of N-CDs-Apt and β-Co(OH)2 nanoplates are 150 nmol/L and 100 μg/mL, respectively. The pH of the TE buffer should be 8.0, and the incubation time should be 10 min at 25 °C. The developed fluorescent aptasensor displayed an excellent selectivity for PAT determination with a detection limit of 0.57 pg/mL in the linear range of 1.25 pg/mL-100 ng/mL. The rapid PAT determination in fruit juice samples was realized with good recoveries (96.9–105.8%). The developed fluorescent aptasensor based on the interaction between N-CDs and hexagonal β-Co(OH)2 nanoplates can be a promising method for the rapid and ultrasensitive detection of PAT in agricultural products.