Portable instrument based on color sensor chip for on-site rapid detection of dissolved sulfides in environmental water samples

A molecularly imprinted polymer-based triple-ratio fluorescence nanosensor integrated with a paper-based microfluidic chip for rapid detection of enoxacin

Enoxacin (ENX), a commonly used fluoroquinolone antibiotic, has raised environmental concerns due to its widespread use and resulting pollution. This study presents a novel approach for the rapid and sensitive detection of ENX in aquatic environments using molecularly imprinted polymer-based triple-ratio fluorescence (MIP-TRF) nanosensor. The nanosensor is constructed based on a photoinduced electron transfer (PET) mechanism, combining the high selectivity of molecular imprinting technology with the high sensitivity and anti-interference capability of triple-ratio fluorescence. By optimizing modifiers, eluents, and reaction conditions, the nanosensor demonstrates excellent selectivity and sensitivity, with a detection limit as low as 0.008 mg/L and good linearity over a concentration range of 0.05-7.0 mg/L. The recovery rate in river water samples was between 98.88 % and 102.76 %. To assess the potential application of the sensor, preliminary tests were also conducted by integrating the MIP-TRF nanosensor with a paper-based microfluidic chip, showing that the sensor offers higher detection speed, simplicity, and cost-effectiveness compared to traditional methods. This provides an efficient and convenient solution for the environmental monitoring of ENX and similar contaminants.

Unique hemispherical coordination-drivened pesticide residue probes: Enhanced stability in linear recognition for trifluralin

Trifluralin (TRL) is an effective and persistent herbicide, but its extensive and prolonged use has increasingly posed ecological and environmental health risks, making the development of convenient and rapid TRL detection methods essential for environmental protection and food safety. In the present research, a novel fluorescent probe was designed and developed, Zn-χ-L, for the rapid and selective detection of TRL in complex environments. The sensor demonstrates excellent sensitivity and stability, while also exhibiting significant resistance to interference from other pesticides and metal ions. Moreover, Zn-χ-L exhibited stable performance across various solvents and showed resistance to interference from other pesticides and metal ions. Molecular docking and theoretical calculations indicate that the unique recognition of TRL molecules by Zn-χ-L is related to its specific hemispheric structural feature, which forms strong coordination interactions between Zn-χ-L and TRL through coordination bonds, π-π stacking, and halogen bonds. This special conformation not only enables the formation of coordination bonds but also establishes multiple π-π stacking and halogen bonding interactions between Zn-χ-L and TRL, leading to efficient charge transfer and exceptional probe performance.

Efficient electrochemiluminescence sensor utilizing Zr-PyTCPPMOF for swift hydrogen sulfide detection

The ultrahigh-sensitive detection of H2S is reported using a novel dual-ligand metal-organic framework (MOF) electrochemiluminescence (ECL) sensor. By combining tetrakis(4-carboxyphenyl) porphyrin (TCPP) and 1,3,6,8-tetrakis(4-carboxyphenyl) pyrene (TBAPy) as ligands and employing zirconium as the metal source, a spindle-shaped Zr-PyTCPPMOF was successfully designed and synthesized. Notably, the multiple nitrogen structures of porphyrin provided abundant binding sites for sulfur (S), further enhancing the ECL signal of Zr-PyTCPPMOF. The sensor shows a good linear relationship in the 0.01-100 μM range, with a detection limit reaching 1.18 nM (S/N = 3). When analyzing actual serum samples, the recovery was between 96.6 and 106.2%. Ultimately, the dual-ligand ECL platform based on Zr-PyTCPPMOF achieved trace detection of H2S, which is expected to provide reliable technical support for early environmental monitoring and disease diagnosis.

Eutrophication evolution of lakes in China: Four decades of observations from space

The lake eutrophication is highly variable in both time and location, and greatly restricts the sustainable development of water resources. The lack of national eutrophication evaluation for multi-scale lakes limits the pertinent governance and sustainable management of water quality. In this study, a remote sensing approach was developed to capture 40-year dynamics of trophic state index (TSI) for nationwide lakes in China. 32% of lakes (N = 1925) in China were eutrophic and 26% were oligotrophic, and a longitudinal pattern was discovered, with the 40-year average TSI of 62.26 in the eastern plain compared to 23.72 in the Tibetan Plateau. A decreasing trend was further observed in the past four decades with a correlation of -0.16, which was mainly discovered in the Tibetan Plateau lakes (r > -0.90, p < 0.01). The contribution of climate change and human activities was quantified and varied between lake zones, with anthropogenic factors playing a dominant role in the east plain lakes (88%, N = 473) and large lakes are subject to a more complex driving mechanism (≥ 3 driving factors). The study expands the spatiotemporal scale for eutrophication monitoring and provides an important base for strengthening lake management and ecological services.