Hypochlorite (ClO-) is a highly reactive chemical extensively used in households, public areas, and various industries due to its multiple functions of disinfection, bleaching, and sterilization. However, overuse of ClO- may contaminate the water, soil, air and food, leading to negative impacts on the environments, ecosystems and food safety. Meanwhile, excessive ClO- in human body can also cause severe damage to the immune system. Thus, the development of effective and precise detection tools for ClO- is of great significance to better understand its complicated roles in environments and biosystems. Herein, a new high-performance ratiometric fluorescent probe 2-amino-3-((10-propyl-10H-phenothiazin-3-yl)methylene)-amino)maleonitrile (PD) was developed for effective detection of ClO- in various bio/environmental and food samples. Probe PD exhibits highly-specific ratiometric fluorescent response to ClO- with rapid response (< 1 min), excellent sensitivity (detection limit, 47.4 nM), wide applicable pH range (4 -12), and excellent versatility in practical applications. In practical applications, PD enables the sensitive and quantitative detection of ClO- levels in various water samples, bio-fluids, dairy products, fruits and vegetables with high-precision (recoveries, 97.00 -104.40 %), as well as the successful application for visual tracking ClO- in fresh fruits and vegetables. Furthermore, test strips containing PD offer a visual and convenient tool for quick identification of ClO- in aqueous media by the naked eye. Importantly, the good biocompatibility of PD enables its practical applications in real-time bioimaging of endogenous/exogenous ClO- levels in living cells, bacteria, onion cells, Arabidopsis, as well as zebrafish. This study provided an effective method for visual monitoring and bioimaging of ClO- levels in various environments, foods and living biosystems.

Arsenic (As) contamination of soil and groundwater poses a huge threat to world health by polluting food systems and causing major health problems, such as cancer, cardiovascular disease,skin lesions,kidney damage and other serious health problems. In recent years, there has been a lot of effort into designing, synthesizing, and developing chemosensors for arsenic species. Chemosensors containing heteroatoms such as oxygen, nitrogen, and sulfur provide coordination sites for metal ion detection. This study investigates the study of organic compounds for the fluorimetric and colorimetric detection of As ions in biological, agricultural, and environmental samples. These chemosensors are based on the skeleton of Schiff bases, thiourea, and pyridine. By comparing their identification capabilities, we hope to guide the development of future arsenic chemosensors that are efficient, sensitive, and selective, leading to more accessible methods for arsenic monitoring in a variety of real-world applications.

The overapplication of chemical pesticides will cause heavy pollution in water, soil, and foodstuff, and cause irreversible damage to the ecological environment and human health. Therefore, it is imperative to develop a highly sensitive and reliable tool for detecting pesticide residues in the environment. In this work, a novel nopinone-based fluorescent probe THIP-OCP for the detection of parathion-methyl was constructed from BchE inhibition principles. The ester bond in THIP-OCP was hydrolyzed by BchE, leading to the release of the fluorophore THIP-OH and a significant enhancement of the fluorescence signal at 547 nm. However, parathion- methyl could inhibit BchE activity significantly and resulted in fluorescence quenching at 547 nm. Probe THIP-OCP was effectively used to detect BchE and parathion-methyl, and the detection limits were as low as 8.56 U/L and 0.79 mu g/mL, respectively. A portable smartphone-based analysis platform for quantitative and qualitative analysis of parathion-methyl in soil was developed from probe THIP-OCP. This probe can also be used to detect butyrylcholinesterase (BchE) and parathion-methyl in living cells and zebrafish, providing a new tool for monitoring BchE and parathion-methyl in living systems, which is helpful for protecting human life and health. Therefore, the probe THIP-OCP is regarded as a promising tool for monitoring environmental safety and biological health systems.

Transmedia migration of water is the key factor influencing the bond and shear mechanical properties of the interface system between soil and concrete. In numerous engineering projects, failures often occur at the soil-concrete interface, making the study of transmedia water migration in soil-concrete interface systems highly significant. This research based on the tracer properties of fluorescein to conduct a transmedia water infiltration test on silty clay-concrete interface systems. A fluorescent quantitative method was proposed to determine the moisture content within the concrete profile. The study investigated the migration of the wetting front, changes in water content, moisture distribution across the profiles of both media, and the spatial and temporal variations of soil moisture during the transmedia water migration process. The characteristics of transmedia water migration were compared under different initial soil water contents (IWC). Results demonstrated that the water distribution law of silty clay-concrete interface systems was not monotonous; notably, the water content in the interface area increased significantly. An increase in IWC inhibited the migration of the wetting front and the water content increment of the silty clay, while promoting the progression of saturation. Additionally, the water migration in the concrete was influenced by the silty clay. The proposed fluorescent quantitative method demonstrated high measurement accuracy.

Mercury ion (Hg2+) is one of the most toxic pollutants that can exist throughout the environment and be diffused into water, soil, air, and eventually the food chain. Even a very low level of Hg2+ diffused in living organisms can hurt their DNA and cause the permanent damage of the central nervous system and a variety of consequential disorders. Hence, the development of a sensitive and specific method for the detection of Hg2+ at trace ranges is extremely important as well as challenging. Fluorometric detection assays based on graphene quantum dots (GQDs) and carbon quantum dots (CQDs) offer considerable potential for the determination and monitoring of heavy metals due to their fascinating properties. Although the quantum yield of GQDs and CQDs is sufficient for their use as fluorescent probes, doping with heteroatoms can significantly improve their optical properties and selectivity toward specific analytes. This review explores the primary advances of CQDs and GQDs in their great electronic, optical, and physical properties, their synthetic methods, and their use in Hg2+ fluorimetry detection.

Hg2+ is one of the most toxic heavy metal ions, which can cause air, soil, and water pollution, seriously damaging human health. Therefore, developing effective analytical methods to detect Hg2+ in environmental systems is particularly important. Fluorescent probes have been widely used to detect Hg2+ due to their advantages, such as high sensitivity, good selectivity, fast response time, and real-time online detection. In this paper, a novel turn-on fluorescent probe (2-(pyren-1-yl)-1,3-oxathiolane, POX) with 1,3-oxathiolane as receptor was designed and synthesized based on Hg2+-promoted deprotection reaction of thioacetal, and H-1 NMR, C-13 NMR, and HRMS characterized its structure. The selectivity, competitiveness, concentration titration, pH titration, time dependence, the limit of detection, and recognition mechanism of POX for the detection of Hg2+ in CH3CH2OH/H2O solution were investigated. The results showed that POX could quickly recognize Hg2+ in a wide pH range and exhibited high selectivity and sensitivity. Adding Hg2+ to the solution of POX resulted in a clear fluorescence emission peak at 386 nm, indicating that POX showed a remarkable turn-on fluorescence for Hg2+, and its recognition process was almost unaffected by other metal ions. Fluorescence titration experiments indicated that POX had a good linear response (R-2=0.999 4) in the range of Hg2+ from 0 similar to 6.5 mu mol.L-1, with a detection limit of 0.168 mu mol.L-1. The RSD of POX for detecting Hg2+ in actual water samples was less than 2.92%. The simple synthesis, easy availability of raw materials, and wide pH applicability of POX suggested that it could be used as a potential tool for the qualitative and quantitative detection of Hg2+ in the environment.

To address the growing and urgent need for quick and accurate food spoilage detection systems as well as to reduce food resource wastage, recent research has focused on intelligent bio-labels using pH indicators. Accordingly, we developed a dual-channel intelligent label with colorimetric and fluorescent capabilities using black lycium anthocyanin (BLA) and 9,10-bis(2,2-dipyridylvinyl) anthracene (DSA4P) as colorimetric and fluorescent indicators within a composite film consisting of chitosan (Cs), whey protein (Wp), and sodium tripolyphosphate (STPP). The addition of STPP as a cross-linking agent significantly improved the hydrophobicity, mechanical properties, and thermal stability of the Cs/Wp composite films under low pH conditions. After the incorporation of BLA and DSA4P, the resulting dual-channel intelligent label (Cs/Wp/STPP/BLA/DSA4P) exhibited superior hydrophobicity, as indicated by a water contact angle of 78.03(degrees). Additionally, it displayed enhanced mechanical properties, with a tensile strength (TS) of 3.04 MPa and an elongation at break (EAB) of 81.07 %, while maintaining a low transmittance of 28.48 % at 600 nm. After 25 days of burial in soil, the label was significantly degraded, which showcases its eco-friendly nature. Moreover, the label could visually detect color changes indicating volatile ammonia concentrations (25-25,000 ppm). The color of the label in daylight gradually shifted from brick-red to light-red, brownish-yellow, and finally light-green as the ammonia concentration increased. Correspondingly, its fluorescence transitioned from no fluorescence to green fluorescence with increasing ammonia concentration, gradually intensifying under 365-nm UV light. Furthermore, the label effectively monitored the freshness of shrimp stored at temperatures of 4 C-degrees, 25( degrees)C, and - 18(degrees) C. Thus, the label developed in this study exhibits significant potential for enhancing food safety monitoring.

The pollution of heavy metals such as Cu2+ is still serious and the discharge of sewage of Cu2+ will cause damage to soil environment and human health. Herein, a biomass-based solid-state fluorescence detection platform (CPUCDs) was developed as fluorescent sensor for detection Cu2+ via fluorescence and colorimetric dual-model methods in real time. CPU-CDs was composed of xylan-derived CDs (U-CDs) and cotton cellulose paper, which exhibiting good reusability, non-toxicity, excellent fluorescence characteristics and high biocompatibility. Further, CPU-CDs displayed high effectiveness and sensitivity for Cu2+ with the detection limit as low as 0.14 mu M, which was well below U.S. EPA safety levels (20 mu M). Practical application indicated that CPU-CDs could achieve precision response of Cu2+ change in real environment water samples with good recovery range of 90 %- 119 %. This strategy demonstrated a promising biomass solid-state fluorescence sensor for Cu2+ detection for water treatment research, which is of great significance in dealing with water pollution caused by heavy metal ions.