Film-based fluorescent sensor for visual monitoring and efficient removal of aniline in solutions and gas phase

Preparation of molecular imprinted fluorescence sensor based on Er3+/ZnS QDs and its selective detection of ciprofloxacin in various matrices

BACKGROUND

Ciprofloxacin is a widely used antibiotic in medicine and agriculture. It can cause pollution to the environment and food, thereby affecting human health.

OBJECTIVE

This study proposes the preparation of molecular imprinted fluorescent sensors and their selective detection of ciprofloxacin, with the aim of achieving specific recognition and accurate detection of ciprofloxacin.

METHODS

Rare earth metal Er3+ is added to ZnS quantum dots to prepare a molecularly imprinted fluorescence sensor (MIP/Er3+/ZnS QDs). The effects of substance concentration, pH value, and time on the fluorescence detection intensity are analyzed to determine the optimal fluorescence detection conditions.

RESULTS

Experimental results showed that the sensor accurately detected ciprofloxacin with a detection limit of 31 nmol/L and the linear range of 0.1-10 μmol/L. The sensor had a recovery rate of 99.7% to 103.5% for ciprofloxacin in milk samples, with a relative standard deviation of less than 5%, indicating accurate determination of ciprofloxacin content.

CONCLUSION

Molecularly imprinted fluorescent sensors have enormous application potential in the monitoring and control of ciprofloxacin, and are of great significance for ensuring environmental and food safety.

Alginate-modified surfactants functionalized metal-organic framework-based fluorescent film sensors for detection and adsorption of volatile aldehydes in water

Volatile aldehydes have an adverse impact on both human health and the environment, therefore, a fast, straightforward, highly accurate detection technique for the simultaneous detection and removal of several aldehydes is eagerly anticipated. Herein, novel APGF@ZIF-8 and APOF@ZIF-8 sensing materials were developed by coating fluorescent alginate-modified surfactants (APGF and APOF) into the ZIF-8 MOFs to produce quite porous fluorescent sensors (SBET up to 1519 m2/g). The detection capacity of the prepared sensors for benzaldehyde, glyoxal, formaldehyde, and acetaldehyde has been examined. The detection mechanism was suggested as hydrogen bonding formation between the sensors and volatile aldehydes as confirmed by Gaussian calculations. All the fluorescence spectra of aldehydes display remarkable linear detection relationships in the range of 0.05-200 μM with the limits of detection (LOD) values in the range of 0.001-0.18 μM (0.106-10.44 ppb). These sensors were utilized successfully to detect multiple volatile aldehydes in river water samples with satisfactory recoveries of 96-107 %. Interestingly, fluorescent APGF@ZIF-8/CS and APOF@ZIF-8/CS films as portable disposable removal techniques for benzaldehyde, glyoxal, formaldehyde, and acetaldehyde from water were fabricated. APOF@ZIF-8/CS exhibited an excellent formaldehyde adsorption capacity of 58.30 mg/g and an adsorption removal efficiency of 93.5 %. The adsorption process of biosorbent on various aldehydes was fitted by Freundlich adsorption isotherm. The adsorption kinetics followed Pseudo-second-order kinetic model.

Simultaneous detection of As(III/V), Cr(III/VI), and Fe(II/III) by a sensor array based on the morphology regulation of CeO2 oxidase

To develop a convenient method for simultaneous detection of As(III/V), Cr(III/VI), and Fe(II/III), three morphologies of CeO2 oxidase have been prepared. Based on the difference in oxidase activity and binding ability with substrate TMB of CeO2 of different morphologies, a 3 (Signal unit) × 6 (Target number) × 5 (Repetition) sensor array was constructed to realize simultaneous detection of six variable valence metal ions As(III/V), Cr(III/VI), and Fe(II/III). The lowest detection limit of the array for metal ions was 1.68 µg/L. The analysis of environmental samples with multiple metal ions (binary and ternary mixtures) co-existing has confirmed that the sensor array can achieve simultaneous qualitative and quantitative results for composite samples. This study not only revealed the influencing factors of crystal morphology regulation on oxidase activity, but also provided a scheme for the morphology detection of easily convertible metal ions in the field through the construction of the sensor array.

Enhancement of the Peroxidase Activity of g-C3N4 with Different Morphologies for Simultaneous Detection of Multiple Antibiotics

The classes and forms of antibiotics directly determine their ecotoxicity and environmental chemical behavior, and developing a sensor array for simultaneous and in situ detection of antibiotics is highly anticipated. In this study, different morphologies of g-C3N4 with different fluorescence properties and peroxidase activity were prepared by regulating the degree of interlayer stacking and planar connectivity. Subsequently, in order to enhance its enzyme activity and amplify the differences in response signals to different antibiotics, three morphologies of g-C3N4/MIL-101(Fe) were prepared by in situ growth of equivalent amounts of MIL-101(Fe) on g-C3N4, respectively. The sensor array constructed based on the cross-response signals between g-C3N4/MIL-101(Fe) and antibiotics not only realized the simultaneous detection of quinolones, furans, tetracyclines, and lincomamides but also could efficiently identify their seven different forms. In the range of 0.2-0.8 ppm, the minimum detection limit for antibiotics was 12 ppb. In addition, the recovery experiments of multicomponent-mixed antibiotics in environmental samples show that the recovery rate remained at 91.42-107.59%, confirming the reliability and practicality of the sensor array. This study not only revealed the influence of crystal morphology regulation on the optical properties and enzyme activities of nanozymes, but also provided support for tracing, ecological remediation, and in situ environmental chemical behavior research of antibiotics.

Simultaneous visual detection of multiple heavy metal ions by a high-throughput fluorescent probe

To develop simultaneous and in-situ detection techniques towards Cr(VI) and Mn(II), Eu/Tb@CDs with white fluorescence were prepared by a one-step hydrothermal method. With the increase of Cr(VI), all fluorescence channels of Eu/Tb@CDs exhibited obvious quenching, and the detection limit (LOD) was 0.10 μM. In the presence of Mn(II), only the fluorescence from Tb and Eu was quenched, while the fluorescence of CDs was not effected. The LOD for Mn(II) was 0.16 μM. More importantly, in the actual water samples where Cr(VI) and Mn(II) coexist, Eu/Tb@CDs can realize their rapid and simultaneous detection by simple spectral calculation. The selective and competitive experiments have also confirmed that the detection of Cr(VI) and Mn(II) was not interfered by common pollutants in groundwater. It is undeniable that the simultaneous detection of multiple targets by one probe not only greatly improves the detection efficiency, but also has important significance for the field monitoring of water quality parameters.

A portable and intelligent logic detector for simultaneous and in-situ detection of Al3+ and fluoride in groundwater

To develop a convenient and intelligent detector for simultaneous and in-situ detection of Al³⁺ and F^- in groundwater, a novel organic probe called RBP has been prepared. With the increase of Al³⁺, RBP showed a significant fluorescence enhancement at 588 nm, and the detection limit was 0.130 mg/L. After combining with fluorescent internal standard CDs, the fluorescence of RBP-Al-CDs at 588 nm was quenched due to the replace of F^- for Al³⁺, while the CDs at 460 nm remained unchanged, and the detection limit was 0.0186 mg/L. For convenient and intelligent detection, an RBP-based logic detector has been developed for simultaneous detection of Al³⁺ and F^-. Within the ultra-trace, low concentration, and high concentration range of Al³⁺ and F^-, the logic detector can achieve rapid feedback on their concentration levels ("U", "L" and "H") through different output modes of the signal lamps. The development of logical detector is of great significance for studying the in-situ chemical behavior of Al³⁺ and F^- and for daily household detection.

New method for morphological identification and simultaneous quantification of multiple tetracyclines by a white fluorescent probe

The threat of tetracycline antibiotics to the environment and human health is attracting widespread attention. The development of morphological analysis and quantitative techniques of multiple tetracyclines is of great significance for the evaluation of biochemical toxicity, wide-spectrum antibacterial property and degradation cycle between different tetracyclines. In this study, the white fluorescent Eu/Tb@CDs was synthesized and applied successfully to the identification and detection of the most widely used tetracycline antibiotics (tetracycline (TC), oxytetracycline (OC), chlortetracycline (CC) and doxycycline (DC)) with detection limits all below 1 nM. For the actual water samples with coexistence of the above 4 tetracyclines, their simultaneous morphology identification and accurate quantitative detection can also be realized through simple spectrometric measurement. In addition, the selective and competitive experiments have been carried out on the pollutants widely present in water, and the results have also confirmed that other pollutants could not interfere with the detection of the above 4 tetracyclines. It is undeniable that this work will conveniently and visually reveal the existence information and geographical distribution characteristics of different tetracycline antibiotics in the environment and their action mechanism on organisms.