High Selectivity For Detection Research Articles

A glutathione-sensitive small molecule fluorescent probe for rapid and facile gut microbiota sensing

The human gut microbiota plays an integral role in the management of human health. Effective detection of gut-derived bacteria and their metabolites, as well as assessing antibiotic susceptibility, are crucial for the treatment of intestinal bacteria-related diseases. Herein, we designed and developed a dual-site (nitrophenyl sulfide group and aldehyde group) fluorescent probe DNO-HC, which could rapidly (∼1 min) respond to glutathione (GSH) with low background fluorescence, high selectivity, and low detection limits (45 nM). Moreover, the probe can be used to evaluate the metabolic levels (GSH) in different gut-derived bacteria and discriminate their Gram status. Remarkably, the assessment of antimicrobial susceptibility to a variety of antibiotics has been successfully accomplished utilizing this probe. It offers a promising strategy for the treatment of diseases associated with bacterial infections.

Cavity-enhanced Faraday rotation spectroscopy for interference-free measurement of OH radical at 2.8 μm

An instrument based on cavity-enhanced Faraday rotation spectroscopy (CE-FRS) operating at 2.8 μm has been developed for interference-free measurement of OH radicals in the laboratory. By off-axis coupling of a continuous-wave laser into a high finesse optical cavity, FRS signal is obtained from balanced detection of time-integrated light intensity leaking out of the cavity in the presence of magnetic field. Radio-frequency white noise (5–520 MHz) was injected into laser current which reduced intensity fluctuations in cavity transmission, thus improved the signal-to-noise ratio of the spectroscopic signal by a factor of 2. The setup provides a simple and robust spectroscopic instrument for in-situ and highly-selective detection of paramagnetic species. We demonstrated the instrument’s capabilities using OH radical with concentration in the range of 1012 molecule.cm−3, generated by microwave discharge of water vapor at low pressure. The CE-FRS instrument exhibited a limit of detection of ∼ 1010 molecule.cm−3 in an integration time of 20 s, which is enhanced by a factor of 2.5 compared to cavity-enhanced wavelength modulation spectroscopy involving an off-axis integrated cavity output spectroscopy approach. A time-resolved FRS signal was recorded in a pulsed microwave discharge regime, giving a millisecond time resolution for the measurement of OH concentration profile. The developed instrument provides a potential analytical tool for the measurement of OH concentration for chemical kinetic study in reactor cells.

Conductive metal-organic framework for ppb-concentration and highly selective SAW hydrogen sulfide sensing at room temperature

Hydrogen sulfide (H2S) sensing is utilized for monitoring the concentration in environment protection and industrial process control, of which high selectivity and ppb detection limit are required. Here, a ppb-concentration and highly selective surface acoustic wave (SAW) H2S sensing has been developed with the Cu3(HHTP)2 MOFs conductive metal-organic frameworks (MOFs), which have been synthesized by connecting Cu2+ with the organic ligands via hydrothermal process. Typically, as-prepared Cu3(HHTP)2 MOFs take on shapes including nanoparticles and nanorods. Beneficially, the SAW H2S sensing presents excellent selectivity to H2S and enables to detection of H2S as low as 6 ppb at room temperature (∼ 26 °C). Remarkably, the SAW sensor prototypes exhibit high sensitivity (0.02 mV/ppb) to 50–2000 ppb H2S, fast response (T90: 281 s) and 46 day-long stability at room temperature. Theoretically, such excellent H2S SAW sensing performance might be attributed to the interaction between Cu ions and H2S molecules and the strong acoustoelectric effect of SAW. Practically, our ppb-concentration and highly selective H2S SAW sensing have the potential in the real-time detection of H2S.

Non-destructive visual detection of fresh food spoilage

Two coumarin derivatives SWJT-33 and SWJT-34 were synthesized as probes for the detection of cadaverine (Cad). Among them, SWJT-34 exhibits high selectivity and low detection limits for Cad using fluorescence or UV–vis spectrum. The detection limits for Cad were calculated to be 0.018 μM by fluorescence spectrum and 0.34 μM by UV–vis spectrum, which was much lower than those of most of reported probes. The probe could realize colorimetric and ratiometric detection of Cad because an aza-Michael addition reaction occurred between SWJT-34 and Cad to form the Schiff base compound as a product. In addition, SWJT-34 could be fabricated as portable test strips for the selective detection of Cad in vapor, and the corresponding detection limits were calculated to be 1.88 ppm in the fluorescent mode and 57 ppm in UV–vis mode, respectively. Additionally, these test strips could be used to test the freshness of Rottweiler shrimp and pork at different temperatures.

Fe7S8 nanosheets- catalyzed colorimetric and fluorescence dual ratio sensing for high selectivity detection of ascorbic acid

By using Fe7S8 nanosheets (NSs) as catalyst, O-phenylenediamine (OPD) as chromogenic substrate, H2O2 as oxidant, and ascorbic acid (AA) as regulator, a dual ratio colorimetric and fluorescence sensing system for determining AA was constructed. The inherent peroxidase like activity of Fe7S8 NSs enables it to catalyze the oxidation of OPD in the existence of H2O2, resulting in the formation of yellow-colored 2, 3-diaminophenazine (DAP) with a characteristic absorption peak at 450 nm and a fluorescence emission peak at 560 nm. However, the presence of AA could suppress the oxidation of OPD and induce the generation of quinoxaline derivative (QXD) 3-(dihydroxyethyl) furo [3,4-b] quinoxaline-1-one with absorption and fluorescence emission peaks located at 345 and 435 nm, respectively. Thus, employing the absorption of QXD at 345 nm and emission at 435 nm as the reporting signals, and the absorption of DAP at 450 nm and emission at 560 nm as the reference signals, a ratio colorimetric (A345/A450) and ratio fluorescence (F435/F560) dual signal detection method for AA was developed. Under the optimized conditions, the value of A345/A450 was found to be linear with AA concentration in the ranges of 1.0–40 μM and 40–100 μM, and the value of F435/F560 was strongly correlated with AA concentration in the ranges of 1.0–30 μM and 30–100 μM. When applied for the assay of AA in human serum samples, an acceptable recovery ranging from 93.1 to 106.6 % was obtained, confirming the potential of the sensing system in practical applications.

High-sensitive electrochemical sensor based on Ni/NiCx-integrated functional carbon nanotubes for simultaneous determination of acetaminophen and dopamine

In complex environmental substance monitoring, the simultaneous detection of single and multiple substances with high sensitivity has been a research focus in the field of electrochemical sensors. Rational selection of appropriate dopants to optimize the electrode material is crucial in this regard. In this work, we employed a multi-doping strategy to effectively enhance the electrocatalytic performance of multi-walled carbon nanotubes (MWCNTs). By doping Ni/NiCx onto MWCNTs, we successfully constructed a heterojunction material (Ni/NiCx-N-MWCNTs). The successful doping of Ni/NiCx allows for the synergistic effects of multiple elements. Ni/NiCx serves as a conductive bridge, forming a three-dimensional network of nanotubes, which effectively reduces the aggregation of carbon nanotubes, exposes more active sites, and enhances electrocatalytic activity. The electrochemical sensor based on Ni/NiCx-N-MWCNTs demonstrated high sensitivity, selectivity, and simultaneous electrochemical detection for acetaminophen (1–150 μM, limit of detection (LOD)=0.56 μM) and dopamine (1–80.0 μM, LOD=0.19 μM). Its excellent reproducibility (relative standard deviation (RSD)=2.01 %) and interference resistance provide Ni/NiCx-N-MWCNTs with significant advantages over other electrode materials, indicating a promising application potential.

A novel triphenylamine-based fluorescent probe for high selectivity and sensitivity detection of UO22+ in water samples and living cells

Here, we report a novel triphenylamine-based fluorescent probe AIU for detecting UO₂2⁺. The probe AIU exhibited good selectivity, low detection limit (67 nm), and rapid response time(80s). The coordination mechanism of AIU toward UO₂2⁺ was investigated through theoretical calculations and other methods such as HPLC-MS. Moreover, AIU has demonstrated efficacy in detecting UO₂2⁺ in real water samples and in living cells.

Fabrication of Graphene-based Ammonia Sensors: A Review

Abstract: Graphene gas sensors have gained much scientific interest due to their high sensitivity, selectivity, and fast detection of various gases. This article summarizes the research progress of graphene gas sensors for detecting ammonia gas at room temperature. Firstly, the performance and development trends of the graphene/semiconductor Schottky diode sensor are discussed. Secondly, manufacturing methods and the latest developments in graphene field-effect transistor sensors are reviewed. Finally, the basic challenges and latest efforts of functional ammonia gas sensors are studied. The discussion delves into each sensor type's detection principles and performance indicators, including selectivity, stability, measurement range, response time, recovery time, and relative humidity. A comparative analysis is conducted to highlight the progress achieved in research, elucidating the advantages, disadvantages, and potential solutions associated with various sensors. As a result, the paper concludes by exploring the future development prospects of graphene-based ammonia sensors.

Innovative voltammetric techniques for bumadizone analysis in pharmaceutical and biological samples: emphasizing green, white, and blue analytical approaches

There are no documented electroanalytical methods for quantifying the anti-inflammatory drug bumadizone (BUM) in pharmaceutical or biological matrices. So, a new voltammetric method was developed to determine BUM at nano concentrations in pharmaceutical forms, in the presence of its alkaline degradant, and in biological fluids. Five electrodes were tested, including three nano-reduced graphene oxide (nRGO) electrodes (5%, 15%, and 20%), a carbon paste electrode (CPE), and a 10% nRGO-modified CPE. The 10% nRGO-modified electrode showed the best performance, offering high selectivity and low detection limits, with good linearity in the concentration range of 0.9 × 102 to 15 × 102 ng mL−1. Differential pulse voltammetry successfully applied this electrode for BUM determination in various samples, achieving excellent recovery without preliminary separation. The method was validated according to ICH guidelines and compared favorably to the reference method. Its environmental impact was assessed using AGREE and Eco-scale metrics in addition to the RGB algorithm, showing superior greenness and whiteness profiles due to safer solvents and lower energy consumption, along with high practical effectiveness using the BAGI metric.

Lanthanide Complexes Based on Rigid Benzimidazole Carboxylic Acid Ligand: Sensing of Nitrobenzene, Fe(III) Ions, and Adsorption of Dyes

ABSTRACTFive new lanthanide complexes {[Sm(H2L)(H2O)4(Cl)]⋅H2O⋅Cl}n (1), {[Eu(H2L)(H2O)4Cl]⋅Cl}n (2), {[La(H2L)(H2O)4Cl]⋅Cl}n (3), {[Pr(H2L)(H2O)4Cl]⋅Cl}n (4), {[Ce(H2L)(H2O)4Cl]⋅Cl}n (5) (H3L = 2‐hydroxy‐5‐(5‐(hydroxy‐λ2‐methoxy)‐1H‐benzo[d]imidazole‐5‐carboxylic acid) were successfully synthesized under solvothermal method. 1 exhibits a two‐dimensional (2D) network structure, whereas 2–5 feature one‐dimensional (1D) chain structure. The fluorescence investigations demonstrated that 1–5 could be the fluorescent sensor for nitrobenzene (NB) and Fe(III) ions with high selectivity, sensitivity, and low detection limits. Furthermore, 1–5 displayed the good adsorption to anionic dye Congo red (CR), and the adsorption capacities were 140.5, 206.5, 212.5, 111.5, and 211.5 mg·g−1, respectively.

Enhanced simultaneous adsorption and detection of mercury (II) using functionalized metal − organic framework with defect structures

Designing adsorption materials with high selectivity and sensitive detection is crucial for heavy metal removal. In this study, we introduced thiol, oxime, and thiourea functional groups, containing S, N, or both N and S elements, into the metal − organic framework (MOF-808, Zr6O4(OH)4(H3BTC)2(HCOO)6) to enhance its adsorption and detection capabilities for Hg2+. Moreover, by carefully controlling the molar ratio of the metal source, tricarboxyl and monocarboxyl ligands, we tailored the defects of MOF-808. The thiourea-modified materials demonstrated a record-breaking adsorption capacity (957.94 mg·g−1, 1.99 times that of unmodified materials) and distribution coefficient (743333 mL·g−1) for Hg2+, substantially exceeding that of other ions (separation factor of 105,086 for Hg2+/Zn2+). The material also showed excellent recoverability during ten consecutive cycles in Hg2+ adsorption. Furthermore, the modified MOF-808 displayed selective detection for Hg2+ with a high photochemical quenching coefficient (Ksv = 156.0 M−1). Theoretical calculations indicate that the thiourea group of MOF-808 favors the energetically advantageous Hg2+ capture and detection. These findings underscore the significance of MOF modification and defects engineering as vital strategies for optimizing the simultaneous removal and detection of heavy metal ions.

Design and development of an azo dye‐based ultra‐sensitive chemosensor for the ubiquitous organic anion in aqueous solutions

AbstractOxalate plays a crucial role in various biological and industrial applications. Its involvement in diseases, drug‐ and toxin‐induced disorders, and disruption of industrial processes makes it a high‐priority chemical for the development of more precise, selective, and straightforward analytical methods. Herein, an innovative and efficient strategy for sequentially measuring Cu2+ and oxalate ions is reported. During an indicator displacement process, where Cu2+ and azo dye, ArsenazoIII (AAIII), are used as receiver and indicator, respectively, oxalate (C2O42−) is measured by a colorimetric method. Proof of concept results from UV–visible spectroscopy, naked eye, and signal reset of the indicator revealed a more robust interaction of the Cu2+ receptor with C2O42− than the AAIII indicator with high selectivity, good sensitivity, and lower detection limit(4.01 × 10−8 and 3.04 × 10−9mol L−1, for Cu2+ and C2O42−, respectively). The results of measuring C2O42− in actual samples (urine, mushrooms, and spinach) showed the applicability of the existing method. Most importantly, the colorimetric system based on molecular exchange in the indicator dislocation proceeding can serve as a colorimetric INHIBIT logic‐gate. It works like a molecular keypad lock system that can be controlled by two users with two different sets of chemical passwords (inputs) that can be identified through optical paths.

A novel “turn-on” NIR fluorescent probe based on benzothianone for the detection of palladium species and its application in cell and zebrafish

The development of an efficient palladium probe holds significant application value, considering the detrimental impact of palladium contaminants on human health. Thus, it is critical to create a sensitive detection method. To this end, a fluorescent probe TM-TPA-Pd based on benzothianone structure was designed, using allyl carbonate as the Pd0 recognition unit. TM-TPA-Pd exhibited high sensitivity (1.4 eq), selectivity, near-infrared (NIR) fluorescence (798 nm), and low detection limit (0.46 μM) for Pd0 with a rapid “turn-on” fluorescence signal (5 min). Furthermore, TM-TPA-Pd has extremely low cytotoxicity and has been successfully applied to detecting cells and zebrafish, which has great potential for palladium detection in biological systems.

Rational design of a dual-mode fluorescent probe for portable detection of pyriproxyfen in the environment and food

The development of a fluorescent probe for pyriproxyfen (PPF) is crucial due to its potential threat to human health. However, the chemical inertness and low solubility of PPF present significant challenges for the detection of PPF in aqueous solutions using fluorescent probes. Herein, we have originally proposed a complex based on 2-(4-(dimethylamino)phenyl)−3-hydroxy-6,7-dimethoxy-4 H-chromen-4-one (HOF) and serum albumin (SA) as a dual-mode fluorescent probe, HOF@SA. This probe utilizes an indicator displacement assay (IDA) to release the dye HOF from the probe at low PPF concentrations (< 10 µM) and embeds the free dye HOF into the micelle of PPF at high concentrations (> 10 µM). This results in dual-mode fluorescent response characteristics for PPF: a turn-off response at low concentrations and a ratiometric response at high concentrations. An investigation of sensing behavior of HOF@SA for PPF detection exhibits rapid response (< 60 s), high sensitivity (LOD ∼4.7 ppb), high selectivity, and excellent visual detection capability (from cyan to yellow). Moreover, with the aid of a portable device, this method enables to analyze PPF in environmental and food samples. These results promote the advancement of a fluorescent probe approach for PPF analysis in environment and food.

A color-changed fluorescence sensor for pesticide triclopyr 2-butoxyethyl ester based on naphthalimide Schiff-base

Triclopyr 2-butoxyethyl ester is a usual pesticide, however, its excessive use might pose risks to environmental safety. The rapid, simple and in-situ detecting method for triclopyr 2-butoxyethyl ester is of great importance but rarely reported. In this work, the first fluorescent sensor for triclopyr 2-butoxyethyl ester was developed based on a derivative of n-butyl-1,8-naphthimide Schiff-base (NSB). NSB is a typical AIE molecule with good green fluorescence in DMSO-H2O (5:95). The green fluorescence of NSB was transferred into strong blue fluorescence on sensing triclopyr 2-butoxyethyl ester. The high selective detection of NSB for triclopyr 2-butoxyethyl ester was observed among 26 kinds of normal metallic ions and pesticide molecules. The detecting limitation was as low as 2.89 × 10−7 M. The sensing mechanism was confirmed as 1:1 stoichiometric ratio based on the multiple hydrogen bonding and hydrophobic interactions. NSB was applied on sensing triclopyr 2-butoxyethyl ester in real samples of wheat seedlings, sugarcane and broadleaf weedane and water samples, suggesting the excellent application potential on simple, rapid and in-situ detection of triclopyr 2-butoxyethyl ester in daily environments.

Development of Electrochemical and Colorimetric Biosensors for Detection of Dopamine

Neurotransmitters are essential chemical messengers required for proper brain function, and any changes in their concentrations can lead to neuronal diseases. Therefore, sensitive and selective detection is crucial. This study presents a fast and simple colorimetric method for dopamine detection using three reagent solutions: AgNP and MPA, Ag/Au nanocomposite, and mercaptophenylacetic acid. TEM images showed a narrow distribution of Ag and Au nanoparticles with average sizes of 20 nm and 13 nm, respectively, with gold nanoparticles bound to the edges of silver nanoparticles. A paper-based biosensor was created using manual wax printing for the colorimetric detection of dopamine. Visual detection onsite showed color changes with both the silver nanoparticles and mercaptophenylacetic acid mixture and the silver–gold nanoparticle composite. Electrochemical detection using a glassy carbon electrode modified with 8 mM mercaptophenylacetic acid demonstrated high selectivity and sensitivity towards dopamine, with a peak in the range of 0.7–0.9 V. Interferences were minimized, ensuring high sensitivity and selective detection of dopamine.

Dual detection of tryptophan and S2O82− by a simple yet rapid fluorometric half-salamo-based chemodosimeter in actual water samples

Tryptophan (Trp) and persulfate (S2O82−) are attracting extensive attention because they have significant influence on biological reactions and the natural environment. Thus, developing a novel method for simultaneous detection of Trp and S2O82− is significant and challenging. Herein, a new type of fluorescent chemodosimeter HL based on a half-salamo was synthesized, which has specific recognition for Trp and S2O82−. The chemodosimeter HL showed high selectivity and rapid detection for Trp and S2O82− over various interfering analytes, and the limits of detection of the HL for Trp and S2O82− were 1.2 × 10−7 and 9.8 × 10−7 M, respectively. The response mechanism of HL for Trp and S2O82− was confirmed by ESI-MS, Job′s plot, 1H NMR titration & DFT calculations. Additionally, the applicability of HL for the detection of Trp and S2O82− was investigated in actual water samples, indicating its potential for usefulness.

Metal organic framework-derived porous Ni-doped In2O3 for highly sensitive and selective detection to hydrogen at low temperature

Achieving high sensitivity and selective detection at low temperature is of great significance for hydrogen leakage monitoring and early warning. As a very promising hydrogen sensitive material, In2O3 still faces great challenges in achieving high-performance hydrogen sensing at low temperatures due to inherent defects such as low specific surface area and limited active sites. Here, we prepared Ni-doped In2O3 mesoporous nanomaterials using metal organic framework (MOF) as sacrificial templates. The prepared Ni-doped In2O3 exhibited mesoporous structures with small diameters (2–3 nm), which could be used as effective molecular sieves for the selective detection of hydrogen. The high specific surface area (72.0 m²/g) provided numerous active sites for surface redox reactions, resulting in a remarkable hydrogen sensing response. Notably, gas sensitivity tests demonstrated that the Ni-doped In2O3 gas sensor achieved optimal hydrogen detection performance at 100°C. Particularly, the 3 at% Ni-doped In2O3 nanomaterials exhibited a high response of 12.5–100 ppm hydrogen, along with favorable response/recovery time and a practical limit of detection down to 5 ppm. Furthermore, the Ni-doped In2O3 sensor exhibited excellent reversibility, reproducibility, selectivity and long-term stability. In addition, simulation calculations based on molecular dynamics (MD) and density functional theory (DFT) show that molecular sieve effect is the main reason for the enhanced selectivity, and Ni doping induced oxygen vacancy (OV) defects could enhance gas adsorption. This work could provide technical support for leak detection and warning during hydrogen use, storage and transportation in the future.

Cascading oxidoreductases-like nanozymes for high selective and sensitive fluorescent detection of ascorbic acid

Cascading oxidoreductases-like nanozymes for high selective and sensitive fluorescent detection of ascorbic acid

A Novel Multiarmed Bifunctional PEG Derivative for the Preparation of Mass Spectrometry Ion Sources with Antifouling Property and High Selectivity.

It is challenging to prepare a highly selective mass spectrometry (MS) ion source for the rapid and highly sensitive detection of analytes, especially mycotoxins. In this study, an amino and tetrazine bifunctionalized multiarm PEG derivative (NH2HCl-4armPEG10K-(MTz)3), which can be easily immobilized on the substrate by the addition reaction between amino and polydopamine, was used for the preparation of MS ionization substrate. NH2HCl-4armPEG10K-(MTz)3 can also be used as a linker to immobilize sufficient streptavidin (SA) on the surface of the substrate by a click reaction. The process further promotes the immobilization of broad-spectrum antibodies (3D4), which were used as the recognition element for ZEN and its metabolites. The prepared SSS-Au-PDA-4armPEG10K-SA-3D4 not only can rapidly enrich ZEN and its metabolites with high selectivity but also shows good antifouling properties in the matrix. After simple sample preparation, the prepared SSS-Au-PDA-4armPEG10K-SA-3D4 can be directly coupled with MS to achieve high sensitivity (LODs: 0.18-0.66 ng/mL, LOQs: 0.5-1.0 ng/mL) and selective detection of ZEN and its metabolites in the matrix. At the same time, satisfactory recoveries (83.60-97.80%) and precision (RSD: 2.80-9.10%) can also be obtained. The prepared SSS-Au-PDA-4armPEG10K-SA-3D4 is expected to provide a powerful tool for the rapid and highly sensitive determination of multiple targets by MS.