Detection Of Oxytetracycline Research Articles

Z-scheme Bi2S3-carbon nitride heterojunction photoanode activated efficient photoelectrochemical aptasensing of oxytetracycline and insights into the mechanism

A photoelectrochemical (PEC) aptasensor for sensitive and selective detection of oxytetracycline (OTC) was designed and constructed based on a novel Z-scheme heterojunction of bismuth sulfide-carbon nitride (Bi2S3-C3N4) as photoactive material. Since the photogenerated electron-hole pairs can be effectively separated by the Z-scheme route, the photocurrent intensity of the constructed Bi2S3-C3N4 heterojunction was about 2.0 times higher than that of pure Bi2S3. Specifically, we disclosed that the increased photocurrent of the aptasensor with the target OTC was ascribed to the oxidation by the generated holes in the Bi2S3-C3N4 based PEC system, which was further validated by electron spin resonance technique. Under the optimized experimental conditions, the photocurrent gradually increased with the increasing of OTC concentration, the proposed PEC aptasensor has the advantages of satisfying linear range (from 1 ×10−12 to 1 ×10−6 M), low detection limit (6 ×10−13 M), excellent selectivity, reproducibility, and stability for OTC detection. In addition, the designed PEC aptasensor has been successfully used for the detection of OTC in soil samples.

A smartphone-assisted optosensingplatform based on chromium-based metal-organic framework signal amplification for ultrasensitive and real-time determination of oxytetracycline.

Ultrasensitive and onsite detection of oxytetracycline (OTC) is of vital significance for ensuring public health. Herein, a novel and versatile fluorescence biomimetic nanosensor, Mg,N-CDs@MIL-101@MIP, was elaborately tailored for the assay of OTC. MIL-101 with extraordinarily high surface area and porosity, as a favorable supporter, suppressed self-quenching of Mg,N-CDs and boosted mass transfer rate, realizing signal amplification. As an ultrasensitive signal transducer, high luminescent Mg,N-CDs yielded conspicuous fluorescence responses for OTC, enhancing the sensitivity of Mg,N-CDs@MIL-101@MIP. High-affinity imprinting sites further endowed Mg,N-CDs@MIL-101@MIP with superior anti-interference ability and reusability. Given prominent merits, Mg,N-CDs@MIL-101@MIP demonstrated a good linear range (0.05-40μgmL-1) with a lower limit of detection (16.8ngmL-1), supplying high accessibility to realize ultrasensitive and highly selective measurement of OTC in samples. Additionally, to attain precise onsite profiling of OTC, an intelligent sensing platform was developed by integrating Mg,N-CDs@MIL-101@MIP with a portable smartphone-assisted optical device. As both signal reader and analyzer, smartphone can instantly capture concentration-dependent fluorescent images and accurately digitize them, accomplishing quantitative analysis of OTC. More delightfully, the portable platform was utilized for visual determination of OTC in milk samples with satisfactory results, offering a promising tool for the high-performance onsite evaluation of food safety and environmental health.

Ratiometric Fluorescence Probe Based on Deep-Red Emissive CdTe Quantum Dots and Eu3+ Hybrid for Oxytetracycline Detection

Oxytetracycline (OTC) is an environmental pollutant caused by the abuse of antibiotics, and its content in water is closely related to human health. Therefore, the development of a simple, rapid, and accurate method to detect OTC has become desirable. In this work, a ratiometric fluorescence probe based on deep red emissive CdTe quantum dots (QDs) modified by mercaptopropionic acid and Eu3+ is developed to accurately and rapidly detect OTC in water. After the addition of OTC, the photoluminescence intensity of CdTe QDs at 698 nm remains almost unchanged, while the peak at 617 nm intensifies within 40 s due to the coordination of Eu3+ with OTC. An excellent linear relationship is present between the photoluminescence intensity ratio of I617/I698 and the concentration of OTC. The limit of detection of the probe towards OCT is 5.4 nM. In addition, the probe shows good selectivity and anti-interference ability for OTC in the presence of other antibiotics, including other antibiotics, ions, and amino acids. The probe has been successfully applied to detect OTC in actual samples, demonstrating its potential for environmental application.

Synthesis of molybdenum disulphide complex fluorescent probe and its application in the detection of oxytetracycline

Synthesis of molybdenum disulphide complex fluorescent probe and its application in the detection of oxytetracycline

Synthesis of molybdenum disulfide complex fluorescent probe and its application in the detection of Oxytetracycline

Synthesis of molybdenum disulfide complex fluorescent probe and its application in the detection of Oxytetracycline

Copper nanoclusters stabilized by D-penicillamine for ultrasensitive and visual detection of oxytetracycline

Copper nanoclusters (DPA@CuNCs) with red fluorescence were successfully synthesized by a one-step method based on D-penicillamine (DPA), which acted not only as a reducing agent but also as a stabilizer. The products were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, particle-size analysis, ultraviolet–visible spectrophotometry, and fluorescence spectrometry. When the excitation wavelength was 280 nm, DPA@CuNCs emitted bright red fluorescence at 640 nm with a fluorescence quantum yield of 5.8 %. Due to the inner filter effect, oxytetracycline (OTC) effectively quenched the fluorescence of DPA@CuNCs, and then DPA@CuNCs were applied to the trace detection of OTC. The method showed a good linear range for OTC from 5 to 60 μmol/L, with a detection limit of 0.026 μmol/L and a correlation coefficient R2 of 0.9983. Moreover, a paper-based sensor for the visual detection of OTC has been developed, which can conveniently and rapidly distinguish the concentration ranges of OTC through the color changes of the test papers.

Dual fluorescent aptasensor for simultanous and quantitative detection of sulfadimethoxine and oxytetracycin residues in animal-derived foods tissues based on mesoporous silica.

Herein, we developed a dual fluorescent aptasensor based on mesoporous silica to simultaneously detect sulfadimethoxine (SDM) and oxytetracycline (OTC) in animal-derived foods. We immobilized two types of aptamers modified with FAM and CY5 on the silica surface by base complementary pairing reaction with the cDNA modified with a carboxyl group and finally formed the aptasensor detection platform. Under optimal conditions, the detection range of the aptasensor for SDM and OTC was 3-150 ng/mL (R 2 = 0.9831) and 5-220 ng/mL (R 2 = 0.9884), respectively. The limits of detection for SDM and OTC were 2.2 and 1.23 ng/mL, respectively. The limits of quantification for SDM and OTC were 7.3 and 4.1 ng/mL, respectively. Additionally, the aptasensor was used to analyze spiked samples. The average recovery rates ranged from 91.75 to 114.65% for SDM and 89.66 to 108.94% for OTC, and all coefficients of variation were below 15%. Finally, the performance and practicability of our aptasensor were confirmed by HPLC, demonstrating good consistency. In summary, this study was the first to use the mesoporous silica-mediated fluorescence aptasensor for simultaneous detection of SDM and OTC, offering a new possibility to analyze other antibiotics, biotoxins, and biomolecules.

A Highly Sensitive and Selective Nano-Fluorescent Probe for Ratiometric and Visual Detection of Oxytetracycline Benefiting from Dual Roles of Nitrogen-Doped Carbon Dots

The specific detection of oxytetracycline (OTC) residues is significant for food safety and environmental monitoring. However, rapid specific determination of OTC from various tetracyclines is still challenging due to their similar chemical structures. Here, nitrogen-doped carbon dots (NCDs) with excitation and pH-dependent optical properties and a high-fluorescence quantum yield were successfully synthesized, which were directly employed to fabricate a dual-response fluorescence probe by self-assembly with Eu3+ (NCDs/Eu3+) for the ratiometric determination of OTC. The addition of OTC into the probe greatly enhances the characteristic emission of Eu3+ due to the "antenna effect", and the incorporation of NCDs into the probe further improves the Eu3+ fluorescence by remarkably weakening the quenching effect caused by H2O molecules and efficiently shortening the distance of energy transfer from OTC to Eu3+. Meanwhile, the fluorescence of NCDs apparently decreases due to aggregation-caused quenching. The results demonstrate that a ratiometric detection of OTC (0.1-25 µM) with a detection limit of 29 nM based on the double response signals is achieved. Additionally, visual semi-quantitative assay of OTC can be realized with the naked eye under a 365 nm UV lamp according to the fluorescence color change of the as-fabricated probe. This probe exhibits acceptable specificity and anti-interference for OTC assay, holding promise for the fast detection of OTC in real water and milk samples.

Novel and Highly Sensitive Electrochemical Sensor for the Determination of Oxytetracycline Based on Fluorine-Doped Activated Carbon and Hydrophobic Deep Eutectic Solvents.

Residues of oxytetracycline (OTC), a veterinary antibiotic and growth promoter, can be present in animal-derived foods; their consumption is harmful to human health and their presence must therefore be detected and regulated. However, the maximum residue limit is low, and consequently highly sensitive and accurate detectors are required to detect the residues. In this study, a novel highly sensitive electrochemical sensor for the detection of OTC was developed using a screen-printed electrode modified with fluorine-doped activated carbon (F-AC/SPE) combined with a novel deep eutectic solvent (DES). The modification of activated carbon by doping with fluorine atoms (F-AC) enhanced the adsorption and electrical activity of the activated carbon. The novel hydrophobic DES was prepared from tetrabutylammonium bromide (TBABr) and a fatty acid (malonic acid) using a green synthesis method. The addition of the DES increased the electrochemical response of F-AC for OTC detection; furthermore, it induced preconcentration of OTC, which increased its detectability. The electrostatic interactions between DES and OTC as well as the adsorption of OTC on the surface of the modified electrode through H-bonding and π-π interactions helped in OTC detection, which was quantified based on the decrease in the anodic peak potential (E pa = 0.3 V) of AC. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Under optimum conditions, the calibration plot of OTC exhibited a linear response in the range 5-1500 μg L-1, with a detection limit of 1.74 μg L-1. The fabricated electrochemical sensor was successfully applied to determine the OTC in shrimp pond and shrimp samples with recoveries of 83.8-100.5% and 93.3-104.5%, respectively. In addition to the high sensitivity of OTC detection, the proposed electrochemical sensor is simple, cost-effective, and environmentally friendly.

Dual-response fluorescent probe based on nitrogen-doped carbon dots and europium ions hybrid for ratiometric and on-site visual determination of oxytetracycline and tetracycline

Tetracyclines residues, particularly oxytetracycline (OTC) and tetracycline (TC), have raised extensive concern because of their serious adverse effects on human health. Herein, a dual-response fluorescent probe based on nitrogen-doped carbon dots (N-CDs) and Eu3+ hybrid (N-CDs–Eu3+) was developed to selectively determine OTC and TC. The N-CDs act as ancillary ligands of Eu3+ and recognition units of OTC/TC, while the Eu3+ ions chelated with N-CDs can also specifically recognize OTC/TC. Upon inclusion of OTC/TC, an enhancement in Eu3+ emission occurs due to the energy transfer from OTC/TC to Eu3+ and the efficient elimination of quenching effect caused by H2O molecule, which is attributed to the incorporation of N-CDs; while the blue fluorescence emitted by the N-CDs decreases under the inner filter effect and static quenching effect caused by OTC/TC. Based on the double and reverse response signals, the ratiometric detection of OTC and TC in the range of 0.1–45 μΜ and 0.1–30 μΜ is achieved with a detection limit of 0.017 and 0.041 μM, respectively. In addition, the noticeable variation in fluorescence color of the probe is integrated with a smartphone-assisted analysis device for the rapid on-site quantitative assay of OTC, where the detection limit is 0.15 μΜ. The results show that this probe performs with excellent specificity and anti-interference for both OTC and TC, and satisfactory detection results are obtained in lake water, milk, and honey samples, thereby confirming that the probe exhibits promising application in food safety and environmental monitoring.

Directional charge separation on 2D/2D BiVO4/MXene for the enhanced photoelectrochemical detection of oxytetracycline antibiotic in water

The development of a rapid yet efficient detection method is quite urgently needed to address the growing great human health concerns caused by immoderate emissions of oxytetracycline (OTC) antibiotics in water. This work reports a novel photoelectrochemical (PEC) sensor with 2D/2D BiVO4/Ti3C2 for detecting OTC in water. Through multiple characterizations, the formation of BiVO4/Ti3C2 nanocomposites and their superior photo-electronic activities were confirmed. Under visible light irradiation, when electrons transfer from excited BiVO4 to Ti3C2, small Ti3C2 nanosheets worked as the electron trap sites, resulting in efficiently directional charge separation. The rapid photocurrent responses of BiVO4/Ti3C2 are linearly related to the concentration of OTC in the range of 0.1-200 nM, with the detection limit (LOD) of (S/N = 3) 0.03 nM. In addition, the obtained BiVO4/Ti3C2 sensor possessed good stability, reproducibility and selectivity, providing a great potential in the practical application of OTC detection in water.

A self-powered photoelectrochemical oxytetracycline aptasensor: An integrated heterojunction photoanode of metal-organic framework derived ZnO nanopolyhedra/graphitic carbon nitride with high carrier density

The development of effective strategies for the detection of oxytetracycline (OTC) in soil is of great importance for preserving agri-environmental safety and human health. Herein, a novel photoactive material of metal-organic framework (MOF) derived ZnO nanopolyhedra/graphitic carbon nitride (ZnO/g-C3N4) heterojunction was designed by mixing calcination of zeolite imidazole framework-8 (ZIF-8) and melamine. A self-powered photoelectrochemical aptasensor for the sensitive and selective detection of OTC in soil was proposed using ZnO/g-C3N4 as the photoanode. The photoactivity of the MOF derived ZnO nanopolyhedra was regulated effectively by the introduction of g-C3N4, which resulted in a 7-fold increase in the photocurrent of the ZnO nanopolyhedra at a bias potential of 0 V. It was assigned to the higher carrier density of ZnO/g-C3N4. By virtue of the amplified photocurrent of ZnO/g-C3N4, the specificity of the OTC aptamer and the anti-interference ability of the self-powered sensing method, the designed aptasensor demonstrated the advantages of a wide linear range (0.005–200 nM), low limit of detection (1.49 × 10−3 nM), good selectivity and good reproducibility. For real soil sample analysis, satisfactory recoveries were obtained and further verified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Detection of Oxytetracycline Using an Electrochemical Label-Free Aptamer-Based Biosensor.

One of the most effective ways to detect and measure antibiotics is to detect their biomarkers. The best biomarker for the control and detection of oxytetracycline (OTC) is the OTC-specific aptamer. In this study, a novel, rapid, and label-free aptamer-based electrochemical biosensor (electrochemical aptasensor) was designed for OTC determination based on a newly synthesized nanocomposite including multi-walled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs), reduced graphene oxide (rGO), and chitosan (CS), as well as nanosheets to modify a glassy carbon electrode, which extremely enhanced electrical conductivity and increased the electrode surface to bind well with the amine-terminated OTC-specific aptamer through self-assembly. The (MWCNTs-AuNPs/CS-AuNPs/rGO-AuNPs) nanocomposite modified electrode was synthesized using a layer- by-layer modification method which had the highest efficiency for better aptamer stabilization. Differential pulse voltammetry (DPV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) techniques were used to investigate and evaluate the electrochemical properties and importance of the synthesized nanocomposite in different steps. The designed aptasensor was very sensitive for measuring the OTC content of milk samples, and the results were compared with those of our previously published paper. Based on the calibration curve, the detection limit was 30.0 pM, and the linear range was 1.00–540 nM for OTC. The repeatability and reproducibility of the aptasensor were obtained for 10.0 nM of OTC with a relative standard deviation (RSD%) of 2.39% and 4.01%, respectively, which were not affected by the coexistence of similar derivatives. The measurement in real samples with the recovery range of 93.5% to 98.76% shows that this aptasensor with a low detection limit and wide linear range can be a good tool for detecting OTC.

Conformational fixation induced fluorescence turn-on of oxytetracycline coordinated on aluminum-based metal-organic frameworks for ultrasensitive sensing application

Since the abuse of oxytetracycline (OTC) has brought serious environmental problems, it is of great practical significance to develop sensitive OTC fluorescent probes to quantify environmental OTC residues. Herein, the aluminum-based metal-organic framework MIL-53(Al) with microflower morphology and plentiful surface open aluminum sites (denoted as FMIL-53(Al)) was tailored via an acetic acid-assisted solvothermal method and subsequently exploited for ultrasensitive detection of OTC. Compared with conventional hydrothermally synthesized MIL-53(Al), FMIL-53(Al) possesses a larger specific surface with plentiful open aluminum sites, which can selectively coordinate with OTC to fix the molecular conformation. The coordinated OTC molecules undergo a transition from twisted-conformation to extended-conformation, accompanied by an increase in fluorescence quantum yield. As a fluorescent probe, the detection limit of FMIL-53(Al) for OTC is estimated as low as 0.94 nM. Finally, the FMIL-53(Al)-based probe can be applied for the detection of OTC in water samples of fish farm pond, and a portable test paper was successfully fabricated for on-site visual identification of OTC. This work not only demonstrates a novel morphology of MIL-53(Al) for OTC ultrasensitive sensing but also provides an example of morphological engineering to optimize the performance of MOF-based fluorescence sensors.

Highly luminescent copper nanoclusters as temperature sensors and “turn off” detection of oxytetracycline

Polyethyleneimine (PEI), playing roles as a templating agent, has been successfully applied to prepare blue-green-emitting copper nanoclusters (Cu NCs@PEI) on the basis of a rapid chemical reduction synthesis method. Some characterization methods, such as fluorescence spectrophotometer, UV spectrophotometer, Fourier transform infrared instrument (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and fluorescence lifetime, were used for the analysis of physical, chemical and optical properties of Cu NCs@PEI. The Cu NCs@PEI displayed a blue-green emission wavelength at 485 nm and the corresponding quantum yield (QY) was 2.24%. Subsequently, the as-synthesized Cu NCs@PEI were applied for the trace analysis of oxytetracycline on the basis of the inner filter effect (IFE) and static quenching, which caused the fluorescence to be effectively quenched. Additionally, this proposed platform based on the Cu NCs@PEI for oxytetracycline sensing possessed an excellent linear range from 0.5 to 300 μM with a lower detection limit of 0.032 μM (S/N = 3) and correlation coefficient R2 of 0.9972. Surprisingly, as the temperature increased, the fluorescence intensities of Cu NCs@PEI decreased gradually. Thence, the Cu NCs@PEI could be applied for the sensing of temperature. Finally, the practicability of the detection method have been successfully verified by analyzing oxytetracycline in real samples, enlarging its applicable fields for oxytetracycline sensing.

Carbon Dots and Eu3+ Hybrid-Based Ratiometric Fluorescent Probe for Oxytetracycline Detection

Overuse of oxytetracycline (OTC) in livestock farming can cause environmental water pollution, risking human health. It is essential to exploit efficient, fast, and sensitive measures to sense OTC in environmental water samples. In this study, a ratiometric fluorescence probe consisted of blue-fluorescent carbon dots (CDs) and Eu3+ was constructed to detect OTC sensitively and selectively. Upon the addition of OTC, bright red fluorescence was generated due to the aggregation of Eu3+, and the intensity of blue fluorescence of CDs reduced because of the inner filter effect between OTC and CDs. Under 365 nm UV light irradiation, the increasing of OTC concentration from 0 to 10 μM resulted a transformation of probe solution fluorescence color from blue to pick. This CDs–Eu3+ hybrid probe also performed a high selectivity for OTC with minimal interference containing various antibiotics, cations, and amino acids. Importantly, the probe demonstrated a low detection limit of 9.6 nM and a satisfactory recovery efficiency for OTC detection in river and tap water.

Construction of a Photoelectrochemical Sensor Based on FeTCPc@ZnO for the Detection of Oxytetracycline

Construction of a Photoelectrochemical Sensor Based on FeTCPc@ZnO for the Detection of Oxytetracycline

Self-powered photoelectrochemical aptasensor based on MIL-68(In) derived In2O3 hollow nanotubes and Ag doped ZnIn2S4 quantum dots for oxytetracycline detection.

A self-powered photoelectrochemical (PEC) aptasensor was constructed based on MIL-68(In) derived indium oxide hollow nanotubes (In2O3 HNs) and Ag-doped ZnIn2S4 quantum dots (QDs) as sensing matrix for the ultrasensitive detection of oxytetracycline (OTC). The hollow tube structure of the designed photoelectric active platform provided abundant active sites and a larger specific surface area for the immobilization of target recognition unit. The coupling of Ag:ZnIn2S4 QDs and In2O3 HNs can accelerate the transmit and separation of photoinduced charge, and thus greatly increasing the intensity of photocurrent signal. Then, the well-constructed OTC-aptamer was anchored on the modified photoelectrode as an accurate capturing element, achieving the specific detection of analyte. Under optimal conditions, the photocurrent intensity of the PEC aptasensor decreases linearly, with a linear response range of 10-4 -10nmol/L, and a limit of detection (LOD) of 3.3×10-5nmol/L (S/N=3). The developed self-powered aptasensor with excellent reproducibility, stability, and selectivity, provides a potential way to detect antibiotic residues in environmental media.

Direct Z-scheme In2S3/Bi2S3 heterojunction-based photoelectrochemical aptasensor for detecting oxytetracycline in water

The threats of the discharge of antibiotics to the environment and ecology cannot be ignored. Accurate detection of the antibiotic concentration in the matrix is important to determine the contamination status. In this work, we proposed an In2S3/Bi2S3 heterojunction-based photoelectrochemical (PEC) sensor to detect antibiotics in water. The Z-scheme heterostructure promoted the separation of photo-generated carriers and achieved a stronger light response. Gold nanoparticles electrodeposited on the heterojunction surface as anchoring points slightly increased the photocurrent due to its metallic properties and surface plasmon resonance effect. Oxytetracycline (OTC), a broad-spectrum antibiotic was used as the target to test the performance of PEC sensor. Specific junction aptamer was used as the probe to recognize OTC to avoid the interference of complex components in matrix. The composition of In2S3/Bi2S3 heterojunction and the measurement conditions were optimized before the detection of OTC. The presence of OTC resulted in the increase in steric hindrance and the decrease in photocurrent. The PEC aptasensor showed a linear detection range of 0.04–10 nM and a calculated detection limit of 0.007 nM for OTC. In addition, the PEC aptasensor could distinguish OTC from other antibiotics and exhibited a stable light response under 20 continuous on-off irradiations. The practicability of the PEC aptasensor was verified by detecting OTC in river water. The proposed Z-scheme In2S3/Bi2S3 heterojunction-based PEC aptasensor can offer analysis applications for other antibiotics in water by substituting the corresponding aptamer.

Mesoporous silica-based molecularly imprinted fluorescence sensor for the ultrafast and sensitive recognition of oxytetracycline

Molecularly imprinted sensor has been a common chemical sensor for the selective detection of target. Yet, the rapid detection of target was one of the remaining problems, which needs to be diligently improved. Herein, a molecularly imprinted mesoporous silicon material (N-CDs@mMIPs) was successfully prepared for the rapid, sensitive and selective detection of oxytetracycline (OTC). Non-toxic nitrogen-doped carbon quantum dots (N-CDs) with high fluorescence performance was chosen as a detectable fluorescence signal, OTC was the target analysis, 3-Aminopropyltriethoxysilane (APTES) as the functional monomer, tetraethyl silicate (TEOS) as the crossing link agent and cetyl trimethyl ammonium bromide (CTAB) as the pore-foaming agent. N-CDs@mMIPs was synthesized by the removal of CTAB and OTC. Under the optimal test conditions, the resultant N-CDs@mMIPs showed a faster response time within 0.5 min (30 s) and a lower detection limit of 0.035 μmol·L−1 compared with molecularly imprinted sensor without mesoporous structure (N-CDs@MIPs) and other molecularly imprinted sensors. Consequently, N-CDs@mMIPs was applied for the detection of OTC in milk and honey, satisfied recovery rates of 99.80 %–100.60 % and 99.75 %–102.10 % were obtained respectively. In general, the pore structure in mesoporous silicon accelerated the mass transfer rate between target and fluorescent substance, which greatly shortened the detection time of N-CDs@mMIPs to OTC. Furthermore, the pore structure in mesoporous silicon could effectively avoid the self-aggregation of N-CDs, thus improved the sensitivity of N-CDs@mMIPs.