Simultaneous determination of acetamiprid and 6-chloronicotinic acid in environmental samples by using ion chromatography hyphenated to online photoinduced fluorescence detector

Rank annihilation factor analysis for kinetic spectrophotometric determination of morphine in unknown samples

The accurate and selective determination of morphine in biological and pharmaceutical samples remains a critical challenge due to matrix interferences and the need for highly sensitive detection methods. While traditional techniques such as GC-MS, HPLC-UV, and LC-MS/MS offer high sensitivity and selectivity, they often require complex sample preparation, expensive instrumentation, and extensive calibration procedures. In this study, we employ rank annihilation factor analysis (RAFA) in combination with kinetic spectrophotometry to enhance the accuracy and robustness of morphine quantification. RAFA effectively eliminates matrix interferences and resolves overlapping spectral data, thereby improving both sensitivity and selectivity compared to conventional spectrophotometric and chromatographic methods. The Marquis reagent, as a simple, known reagent, was used to acquire kinetic-spectrophotometric data for rank annihilation factor analysis of morphine in several unknown samples. Marquis reagent is composed of a mixture of formaldehyde and concentrated sulfuric acid. Usually, different compounds produce different color reactions when using this reagent. The proposed method was first investigated using simulated data before a couple of tested opiate samples were analyzed by the proposed method to further investigate its performance. The proposed method was also successfully applied to determine morphine in a human urine sample.

Copper regulation of PtRhRuCu nanozyme targeted boosting peroxidase-like activity for ultrasensitive smartphone-assisted colorimetric sensing of glucose

Point-of-care testing (POCT) is promising for biodetection in home healthcare due to advantages of simplicity, rapidity, low cost, portability, high sensitivity and accuracy, and object-oriented POCT platform can be developed by nanozyme-based biosensing. However, designing high-performance nanozymes with targeted regulated catalytic activity remains challenging. Herein, advanced PtRhRuCu quaternary alloy nanozymes (QANs) were rationally designed and successfully synthesized. Cu atoms induced mechanisms of hydrogen peroxide (H2O2) activation and d-band center regulation, achieving high enhancement of peroxide (POD)-like activity and inhibition of oxidase (OXD)-like activity. Inspired by this, a smartphone-assisted colorimetric platform integrated with test strips was established for glucose detection of soft drinks, with a detection limit of 0.021 mM and a recovery rate of 97.87 to 103.36 %. This work not only provides a novel path for tuning specific enzyme-like activities of metal nanozymes, but also shows the potential feasibility for rational design of POCT sensors in actual samples.

Micro solid phase extraction of lead and cadmium using functionalized nanodiamonds@CuAl2O4@HKUST-1 nanocomposite for FAAS analysis in food and water samples

This study focuses on the development and application of a novel nanocomposite (functionalized nanodiamonds@CuAl2O4@HKUST-1)-based µ-SPE method for the sensitive and selective extraction of Pb and Cd from food and water samples. The technique offers high sensitivity and selectivity, allowing accurate measurement of these metals at trace levels. The detection limit is 0.031 µg kg-1 for Cd and 0.052 µg kg-1 for Pb, with a relative standard deviation of 1.7 % for Cd and 4.8 % for Pb. The method was successfully applied to real samples and efficiently quantified Pb and Cd in food and natural water samples. The highest concentrations were found in red lentils (0.274 µg kg-1 Pb) and fresh mint (0.197 µg kg-1Cd), but still below recommended limits set by FAO/WHO (300 µg kg-1 for Pb and 200 µg kg-1 for Cd). It promises to ensure food safety, monitor environmental contamination, and informs regulatory decisions to protect public health.

Rational design of a rapidly responsive and highly selective fluorescent probe for SO2 derivatives detection and imaging

Sulfur dioxide (SO2) is emerging as a double-edged molecule, while plays vital roles in food and biological system. However, the fast, highly sensitive, and versatile fluorescent probe still remains a tough challenge among current reports. Herein, we developed a novel aggregation-induced emission (AIE) fluorescent probe TPE-PN for specifically sensing SO2 derivatives with high sensitivity (150 nmol/L) and rapid response time (10 s) based on intramolecular charge transfer (ICT) mechanism. And the fluorescence at 575 nm decreased tremendously with 31-fold after the probe was treated with HSO3-. Employing the probe, the accurate analysis of HSO3- was successfully realized in food samples, cells, plant tissues, and zebrafishes. Furthermore, we successfully demonstrate the eruption of SO2 derivatives within plant during drought and salt stress processes. Therefore, probe TPE-PN illustrates significant potential for applications in food analysis and monitoring of SO2 derivatives levels in biological systems under stress conditions.

Structure characterization and antioxidant activity of abalone visceral peptides-selenium in vitro

Peptide-selenium chelate is widely regarded as one of the best selenium supplements for relieving selenium deficiency. In this study, abalone visceral peptides (AVP) was used to prepare a new type of peptides-selenium chelate to develop an organic selenium supplement with antioxidant activity. AVP prepared by alcalase exhibited the highest selenium-chelating ability. UV-visible spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy and other structural analysis showed that selenium was mainly bound to the functional groups of -NH, -OH, -CH, CC, CO, and CN bonds on AVP. The formation of AVP-selenium chelate enhanced thermal stability and generated a new crystal structure. The ABTS•+ and •OH scavenging activities of AVP-selenium chelate were increased after in vitro digestion than that of AVP. Conclusively, this study analyzed the chelating mechanism of AVP and selenium from a structural perspective, which would provide a theoretical basis for the development of new selenium supplements.

Chemical profile and quantitative comparison of constituents in different medicinal parts of Lactuca indica during varied harvest periods using UPLC-MS/MS method

Lactuca indica L. cv. Mengzao (LIM), acknowledged as a pivotal "One Root of Medicine and Food", boasts dual applications in both culinary and medicinal domains. This research delves into the influence of various harvest periods (vegetative, budding, blossom, and fruiting) on distinct medicinal parts (roots, stems, leaves, flowers, and seeds) of LIM, employing plant metabolomics to assess its chemical constituents. A total of 66 chemical constituents were identified in LIM, with 11 chemical components emerging as potential markers for distinguish medicinal parts. Notably, nutritional organs exhibited elevated levels of cichoric acid, rutin and chlorogenic acid. Specifically, leaves during the budding stage displayed the highest chicoric acid content at 11.70 mg·g-1. Conversely, reproductive organs showed heightened concentrations of cichoric acid, rutin and chlorogenic acid, with seeds exhibiting the peak cichoric acid content at 4.53 mg g-1. This study enriches our understanding of LIM by offering novel insights into quality assessment and the comprehensive utilization of its diverse parts.

Differential analysis of phytochemistry and antioxidant activity in five citrus by-products based on chromatography, mass spectrometry, and spectrum-effect relationships

The unripe fruit or peel of Citrus aurantium L., Citrus sinensis Osbeck, and Citrus reticulata Blanco are often disregarded due to perceptions of their marginal value. The present study was undertaken to explore the differences in phytochemical composition and bioactive properties of five citrus by-products in China and demonstrate their potential value. 214 compounds were systematically identified using LC-Orbitrap-MS analysis. Among them, narirutin, naringin, hesperidin, and neohesperidin were established as essential compounds for the discrimination and authentication of the five by-products via a combination of LC-MS, HPLC, and TLC techniques. Variations in the antioxidant activity of the by-products were observed, which correlated with their maturity and were attributable to differences in their active ingredients. Moreover, spectrum-effect relationship analysis revealed that the four previously identified differential markers, along with nobiletin and tangeretin, significantly contributed to the differences in antioxidant activity. The results highlight the potential for citrus by-product enhancement and utilization.

Prioritization of control factors for heavy metals in groundwater based on a source-oriented health risk assessment model

Heavy metals (HMs) in groundwater seriously threaten ecological safety and human health. To facilitate the effective management of groundwater contamination, priority control factors of HMs in groundwater need to be categorized. A total of 86 groundwater samples were collected from the Huangpi district of Wuhan city, China, during the dry and wet seasons. To determine priority control factors, a source-oriented health risk assessment model was applied to compare the pollution sources and health risks of seven HMs (Cu, Pb, Zn, Cr, Ni, As, and Fe). The results showed that the groundwater had higher As and Fe contents. The sources of HM pollution during the wet period were mainly industrial and agricultural activities and natural sources. During the dry period, origins were more complex due to the addition of domestic discharges, such as sewage wastewater. Industrial activities (74.10% during the wet period), agricultural activities (53.84% during the dry period), and As were identified as the priority control factors for groundwater HMs. The results provide valuable insights for policymakers to coordinate targeted management of HM pollution in groundwater and reduce the cost of HM pollution mitigation.

Photolysis and photo-enhanced toxicity of three novel designed neonicotinoids: Impact of novel modifying groups

Three novel neonicotinoids (cycloxaprid, flupyradifurone and sulfoxaflor) were designed to reduce the biotoxicity for non-target organisms. These neonicotinoids were photolyzed under light radiation, but it was unclear for the photo-enhanced toxicity and influences of the novel modifying group of the three neonicotinoids. The photolysis and photo-enhanced toxicity experiments were performed for the three neonicotinoids, coupled with quantum chemistry calculation, the mechanisms of photolysis, photo-enhanced toxicity and the influences of novel modifying groups were analyzed. The results showed the photolysis pathways were enriched as compared with previous neonicotinoids due to the composition of modifying groups, singlet oxygen and hydroxyl participated the photolysis of cycloxaprid and flupyradifurone. All tested neonicotinoids exhibited photo-enhanced toxicity to Vibrio fischeri. Due to the difference of photolysis mechanism and toxicity to V. fischeri, the photo-enhanced toxicity curves showed diverse variation when histidine, tert-butanol or dissolved organic matters was in presence of the test solutions. The impact of novel modifying groups over photolysis and photo-enhanced toxicity were analyzed based on the comparison with previous neonicotinoids, theoretically predicted UV-Vis spectra and photo-physical/chemical property descriptors. The data showed the composition of novel modifying group increased the light absorption and photo-chemical activities for the three neonicotinoids.

Mannan oligosaccharides selenium ameliorates intestinal mucosal barrier, and regulate intestinal microbiota to prevent Enterotoxigenic Escherichia coli -induced diarrhea in weaned piglets

Enterotoxigenic Escherichia coli (ETEC) is a common diarrheal pathogen in humans and animals. To prevent and treat ETEC induced diarrhea, we synthesized mannan oligosaccharide selenium (MOSS) and studied its beneficial effect on ETEC-induced diarrhea. A total of 32 healthy weaned piglets (6.69 ± 0.01 kg) were randomly divided into four groups: NC group (Basal diet), MOSS group (0.4 mg/kg MOSS supplemented diet), MOET group (0.4 mg/kg MOSS supplemented diet + ETEC treatment), ETEC group (ETEC treatment). NC and ETEC group fed with basal diet, MOSS and MOET group fed with the MOSS supplemented diet. On the 8th and 15th day of the experiment, MOET and ETEC group were gavaged with ETEC, and NC and MOSS group were gavaged with stroke-physiological saline solution. Our data showed that dietary MOSS supplementation increased average daily gain (ADG) and average daily feed intake (ADFI) and significantly decreased diarrhea index and frequency in ETEC-treated piglets. MOSS did not affect the α diversity and β diversity of ileal microbial community, but it significantly decreased the proportion of lipopolysaccharide biosynthesis in ileal microbial community. MOSS supplementation regulated colonic microbiota community composition, which significantly increased carbohydrate metabolism, and inhibited lipopolysaccharide biosynthesis pathway in colonic microbial community. Moreover, MOSS significantly decreased inflammatory stress, and oxidative stress in ETEC treated piglets. Furthermore, dietary MOSS supplementation significantly decreased intestinal barrier permeability, and alleviated ETEC induced intestinal mucosa barrier irritation. In conclusion, our study showed that dietary MOSS supplementation ameliorated intestinal mucosa barrier, and regulated intestinal microbiota to prevent ETEC induced diarrhea in weaned piglets.

Application of validated migration models for the risk assessment of styrene and acrylonitrile in ABS plastic toys

With styrene and acrylonitrile in ABS plastic toys as examples, this paper introduces to the development of a systematic strategy for studying the chemical migration risk in toys. The approach, included the detection method, establishment of migration model, model verification, and the practical application of the model in risk assessment. First, simple and sensitive methods for detecting analyte residues and migration were developed by headspace GC-MS. Then, the migration models were established based on the migration data from 5 min to 168 h and verified using 11 ABS samples. The results showed that the predicted values of the models and the experimental values had a good fit (RMSE=0.10-8.72 %). Subsequently, the migration of analytes in 94 ABS toys was predicted with these models at specific migration times. The daily average exposure level to styrene and acrylonitrile were estimated for children (3 months to 3 years). At last, the migration models reasonably predicted that the cancer risk of styrene and acrylonitrile in ABS toys were 1.6 × 10^-8-1.4 × 10^-6 and 3.1 × 10^-8-1.6 × 10^-6, respectively. This research contributes to promote toy safety and child health by enriching migration models and risk assessments.

Hydrothermally Grown MoS2 as an Efficient Electrode Material for the Fabrication of a Resorcinol Sensor

Recently, the active surface modification of glassy carbon electrodes (GCE) has received much attention for the development of electrochemical sensors. Nanomaterials are widely explored as surface-modifying materials. Herein, we have reported the hydrothermal synthesis of molybdenum disulfide (MoS₂) and its electro-catalytic properties for the fabrication of a resorcinol sensor. Structural properties such as surface morphology of the prepared MoS₂ was investigated by scanning electron microscopy and phase purity was examined by employing the powder X-ray diffraction technique. The presence of Mo and S elements in the obtained MoS₂ was confirmed by energy-dispersive X-ray spectroscopy. Finally, the active surface of the glassy carbon electrode was modified with MoS₂. This MoS₂-modified glassy carbon electrode (MGC) was explored as a potential candidate for the determination of resorcinol. The fabricated MGC showed a good sensitivity of 0.79 µA/µMcm² and a detection limit of 1.13 µM for the determination of resorcinol. This fabricated MGC also demonstrated good selectivity, and stability towards the detection of resorcinol.

Exploration of emerging environmental pollutants 6PPD and 6PPDQ in honey and fish samples

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPDQ) can pose a threat to human health through the food chain because of their ubiquitous presence in the environment and the biotoxicity on organisms. In this work, we developed modified QuEChERS methods coupled with high performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS) to explore whether 6PPD and 6PPDQ are present in fish and honey. The proposed methods showed acceptable limits of quantification (0.00043-0.001 mg/kg), linearity (R2 > 0.99), recovery (73.3%-108.3%), matrix effect (70.4%-95.6%) and repeatability (RSD < 8.4%). Accordingly, 6PPD and 6PPDQ have been discovered in snakehead, weever and Spanish mackerel fish, while none of which have been detected in the honey samples. The results of our work contributed to increasing public attention to 6PPD and 6PPDQ in agricultural products and provided important reference for the analysis of them.

The Characteristics and Potential Risks of Neonicotinoid Residues in Soils of Different Types of Land Use in Hangzhou

Due to the wide existence of neonicotinoid insecticides (neonics) and their potential impact on ecosystems and human health, they have received special attention in recent years. Soil is not only a sink of neonics but also a source of neonics, so it plays a key role in the ubiquity of neonics in the environment. The purpose of this research was to compare neonics residues in soils of different types of land use and estimate their exposure to different populations via ingestion. A total of 130 soil samples from six different types were collected. The concentrations of seven neonics in soil were simultaneous determined using isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry. The results showed that at least one neonic was analyzed in all samples. The highest average concentration was 3.42 ng/g (clothianidin), followed by 3.39 ng/g (thiamethoxam), 3.06 ng/g (acetamiprid), 2.84 ng/g (imidacloprid), 2.66 ng/g (nitenpyram), 2.43 ng/g (thiacloprid), and 1.89 ng/g (dinotefuran). IMI and ACE were the most commonly found neonics in soil. The neonic levels in different soils varied significantly. The integrated neonic residue in cropland was much higher than that in other types of land. The risk assessment revealed that the average daily dose (ADD) through ingestion contact with soil was acceptable to children and adults. With the increasing evidence that neonics could cause a variety of toxic effects on mammals and humans, ingestion exposure caused by neonics in soil should also receive continuous attention in future studies.

Portable metal-organic framework alginate beads for high-sensitivity fluorescence detection and effective removal of residual pesticides in fruits and vegetables

Pesticides have been emerged as major organic pollutants in environment, owing to widely spread and intrinsic high toxicity in agricultural productivity. Herein, we designed and synthesized a practicability and portable metal-organic framework (MOF) based composite beads MOF-alginate-Ca²⁺-polyacrylic acid (kgd-M1@ACPs) consist of biocompatible host material (sodium alginate) and fluorescent center with blue emission (where kgd-M1 stands for {[Cd(tbia)·H₂O]·2H₂O}_n), which was further developed for high-efficiency and naked-eye 2,6-dichloro-4-nitroaniline (DCN) monitoring in fruits and vegetables. Significantly, the kgd-M1@ACPs shows obvious fluorescent quench towards toxic pesticide DCN with a low limit of detection (LOD) of 0.09 μM and high recovery from 98.08 to 104.37%. Moreover, the kgd-M1@ACPs also presents an excellent DCN adsorption ability. This work demonstrates that smart material kgd-M1@ACPs is expected to be a good candidate for detection and removal of DCN in real fruits and vegetables, which will present a broad prospect for monitoring and treating pesticides.

Synthesis of natural proanthocyanidin based novel magnetic nanoporous organic polymer as advanced sorbent for neonicotinoid insecticides

In this work, a natural proanthocyanidin (PA) based magnetic nanoporous organic polymer (named as PA-MOP) was successfully synthesized for the first time. The PA-MOP possessed high hydrophilic-surface, good magnetic responsiveness and high affinity for neonicotinoid insecticides. It was applied as an advanced magnetic sorbent for extraction of four neonicotinoids (thiamethoxam, imidacloprid, acetamiprid and thiacloprid) from environmental water, peach juice and honey samples prior to HPLC analysis. Under optimal conditions, the limits of detection for the analytes at S/N = 3 were 0.02-0.08 ng mL^-1 for water, 0.03-0.10 ng mL^-1 for peach juice and 0.05-0.16 ng g^-1 for honey sample. The method recoveries were 80.0%-114.8%, with the relative standard deviations below 6.8%. The values of matrix effect were from -1.5% to -9.3%. Based on theory calculation, the extraction mechanism can be attributed to multiple interactions between the PA-MOP and the neonicotinoids, in which hydrogen bonding, π-π stacking and electrostatic interactions are the major interactions.