Emerging carbonaceous material based on residual grape seed applied in selective and sensitive electrochemical detection of fenamiphos.

Fenamiphos (FNP) is a pesticide applied for soil pest control, particularly nematodes, and sucking insects, including aphids and thrips. Despite its use being banned in several countries due to its highly toxic nature for living beings, including mammals, because of its acetylcholine-inhibiting action, it is still marketed for use in agriculture. Therefore, a carbon paste electrode modified with residual grape seed biochar (bSU), served as an electrochemical sensor (E-bSU) for the quantification of fenamiphos in grape juice, tap water, and river water samples. The bSU underwent comprehensive characterization employing elemental, morphological, and spectroscopic analysis techniques. The impact of electrode modification and the electrochemical behavior of the FNP were systematically assessed through cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry. The biochar manifested a microporous surface adorned with dispersed functional groups, enhancing its affinity for organic compounds, particularly the investigated pesticide. Electrode modification and the optimization of analysis parameters resulted in a notable 6-fold amplification of the electrochemical signal of FNP relative to initial conditions, underscoring the efficacy of the E-bSU. The developed methodology attained limits of detection and quantification of 0.3 and 0.9 nmol L⁻1, respectively. Repeatability and reproducibility assays demonstrated relative standard deviations below 5%, underscoring the reliability of the applied electrode. The sensor showcased recoveries ranging from 99.75% to 109.9% across the analyzed samples, highlighting the utility of this selective, stable, and reproducible sensor for fenamiphos determination.

Facial synthesis of fluorine-engineered magnetic covalent organic framework for selective and ultrasensitive determination of fipronil, its metabolites and analogs in food samples.

To improve the adsorption affinity and selectivity of fipronils (FPNs), including fipronil, its metabolites and analogs, a magnetic covalent organic framework (Fe3O4@COF-F) with copious fluorine affinity sites was innovatively designed as an adsorbent of magnetic solid-phase extraction (MSPE). The enhanced surface area, pore size, crystallinity of Fe3O4@COF-F and its exponential adsorption capacities (187.3-231.5 mg g-1) towards fipronils were investigated. Combining MSPE with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), an analytical method was established for the selective determination of fipronils in milk and milk powder samples. This method achieved high sensitivity (LODs: 0.004-0.075 ng g-1), satisfactory repeatability and accuracy with spiked recoveries ranging from 89.9% to 100.3% (RSDs≤5.1%). Overall, the constructed Fe3O4@COF-F displayed great potential for the selective enrichment of fipronils, which could be ascribed to fluorine­fluorine interaction. This method proposed a feasible and promising strategy for the development of functionalized COF and broadened its application in fluorine containing hazards detection.

Ti3C2 MXene/MoS2@AuNPs ternary nanocomposite for highly sensitive electrochemical detection of phoxim residues in fruits.

Phoxim, extensively utilized in agriculture as an organothiophosphate insecticide, has the potential to cause neurotoxicity and pose human health hazards. In this study, an electrochemical enzyme biosensor based on Ti3C2 MXene/MoS2@AuNPs/AChE was constructed for the sensitive detection of phoxim. The two-dimensional multilayer structure of Ti3C2 MXene provides a robust framework for MoS2, leading to an expansion of the specific surface area and effectively preventing re-stacking of Ti3C2 MXene. Additionally, the synergistic effect of self-reduced grown AuNPs with MoS2 further improves the electrical conductivity of the composites, while the robust framework provides a favorable microenvironment for immobilization of enzyme molecules. Ti3C2 MXene/MoS2@AuNPs electrochemical enzyme sensor showed a significant response to phoxim in the range of 1 × 10-13 M to 1 × 10-7 M with a detection limit of 5.29 × 10-15 M. Moreover, the sensor demonstrated excellent repeatability, reproducibility, and stability, thereby showing its promising potential for real sample detection.

Selective and sensitive molecularly imprinted polymer-based electrochemical sensor for detection of deltamethrin.

Electrochemical sensors have a broad range of industrial applications due to their sensitivity, speed, and cost-effectiveness. These sensors enable the continuous monitoring and control of critical parameters in various industrial processes. For instance, they are essential in food safety, environmental monitoring, biomedical applications, and pharmaceutical production. In the food industry, electrochemical sensors facilitate the rapid and reliable detection of contaminants and pathogens in food products, thus enhancing product quality and consumer safety. An electrochemical sensor was developed with the molecularly imprinted polymer (MIP) technique to detect deltamethrin with high sensitivity and selectivity. The sensor was fabricated by electrodeposition of Co3O4 on indium tin oxide (ITO), followed by electropolymerization of o-phenylenediamine with deltamethrin as a template molecule. The template molecules were then removed from the modified electrode by a methanol. The MIP-based electrochemical sensor exhibited high sensitivity and selectivity towards deltamethrin. Under the optimized conditions, the LOD values for the MIP/Co3O4/ITO electrode in the first and second linear regressions were 1.53 nM for linear range of 2.82 nM to 56.5 nM and 0.34 µM for linear range of 0.25 µM to 3.98 µM. Moreover, the LOD values for the NIP/Co3O4/ITO electrode in the first and second regressions were 2.43 nM for the linear range of 3.91 nM to 65.0 nM and 726.0 nM for the linear range of 0.023 µM to 4.5 µM. The developed electrochromic pesticide sensor, being an electrochemical-based molecularly imprinted polymer (MIP) sensor incorporating electrochromic materials, enables both target-specific pesticide detection and visual pesticide identification based on color changes dependent on pesticide concentration. Consequently, this system is more advantageous compared to electrochemical-based MIP sensors, as it provides both qualitative and quantitative determinations. The qualitative assessment aims to enhance the ease of use of the sensor, thereby increasing the potential for it to become a commercially viable product by reducing the need for instrumental devices.

A molecularly imprinted electrochemiluminescence sensor based on mimic enzyme ZIF-90 and MnO2/g-C3N4 magnetic particles for detection of methidathion.

Methidathion (MTDT), a common organophosphorus pesticide with high insecticidal activity, is widely used for pest control. However, the misuse of MTDT leads to widespread residues and endangers human health. Therefore, it is crucial to develop a simple and highly sensitive method for the detection of MTDT residues. Herein, ZIF-90/MnO2/g-C3N4/Fe3O4 composite particles were synthesized: The  MnO2 nanosheets could absorb the energy of the excited g-C3N4 to quench the ECL of g-C3N4 while ZIF-90 acted as a mimetic enzyme to catalyze the formation of thiocholine from MTDT. The thiocholine caused the reduction of MnO2 to Mn2+, restoring the ECL signal of g-C3N4. Combined with molecular imprinting technique, an electrochemiluminescence sensor was constructed for the determination of MTDT. The determination range was 1.00 × 10-9 ~ 7.00 × 10-7 g/L, and the detection limit was 6.58 × 10-10 g/L. Structurally similar organophosphorus pesticides showed no cross-reactivity. The method has high sensitivity and specificity, and has been successfully applied to the determination of MTDT residue in fruits with recoveries in the range 93.75% ~ 102.37%.

Kill two birds with one stone: colorimetric/fluorescence immunosensor based on Au@Pt nanozyme for sensitive detection of imidacloprid.

Gold-platinum (Au@Pt) nanozymes with high catalytic activity and stability were designed to improve the stability of the enzyme-linked immunosorbent assay (ELISA), and a two-mode signal output was used to enhance the sensitivity and confidence of the assay. This study reports the two-mode signal output based on Au@Pt nanozyme to catalyzed 3,3',5,5'-tetramethylbenzidine (TMB) reaction. Oxidized 3,3',5,5'-tetramethylbenzidine (ox-TMB) has wide absorption spectrum, providing excellent optical density capabilities and fluorescence quenching. The detection limits of imidacloprid were 0.88 µg/L and 1.14 µg/L in colorimetric and fluorescence modes, respectively. Multiple-mode strategy improves detection accuracy, increases the confidence of experimental results, and broadens detection modes. Two modes can meet the requirements of accurate and flexible multi-mode sensing in different application situations.

Dissipation Kinetics, Decontamination and Safety Evaluation of Quinalphos Residues in Cauliflower Curd.

A field experiment was conducted to study the persistence and reduction of quinalphos residues in cauliflower curd by applying quinalphos 25 EC twice at 250 g a.i./ha at 10 days intervals. The limit of quantification (LOQ) was 0.05 µg/g, recovery ranged from 97 to 113%, and the relative standard deviation was less than 7%. The initial deposition of quinalphos residues in cauliflower curd was 1.72 µg/g and reached below LOQ level after 15 days of application. Dissipation of the residue followed first-order kinetics with a half-life of 2.32 days. The reduction of quinalphos residue was evaluated using various household processes. The greatest reduction (82%) was observed when washing was followed by cooking or boiling, while the smallest reduction (55.8%) was found when washing alone was performed. A waiting period of 9 days is recommended for safe consumption of cauliflower based on the FSSAI MRL value of 0.1 µg/g.

Neonicotinoid residues in fruits and vegetables in Shenzhen: Assessing human exposure and health risks.

The extensive use of neonicotinoids (NEOs) in agricultural production has led to their pervasive presence in various environmental matrices, including human samples. Given the central role of fruits and vegetables in daily human diets, it is crucial to evaluate the levels of NEOs residues and their potential health risks. In this study, 3104 vegetable samples and 1567 fruit samples from the Shenzhen city were analyzed. Using the relative potency factor (RPF) method, the residue levels of six representative neonicotinoids, including imidacloprid (IMI), acetamiprid (ACE), thiamethoxam (THM), dinotefuran (DIN), clothianidin (CLO), thiacloprid (THI), were systematically evaluated. The estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) for both children and adults were calculated to gauge the prevalence and potential health risks of NEOs in fruits and vegetables. Acetamiprid (ACE) was the most frequently detected NEO in vegetables (69.4%) and fruits (73.9%), making it the predominant contributor to total residues. Further analyses indicated notably higher levels of imidacloprid-equivalent total neonicotinoids (IMIRPF) in root and tuber vegetables (3025 µg/kg) and other fruits (243 µg/kg). A significant strong positive correlation (r = 0.748, P < 0.05) was observed between thiamethoxam (THM) and clothianidin (CLO), possibly due to their shared metabolic pathways. Although the mean HI values for adults and children from daily fruit (adults: 0.02, children: 0.01) and vegetable (adults: 0.02, children: 0.03) intake were generally below safety thresholds, some maximum HI values exceeded these limits, indicating that the potential health risks associated with NEOs exposure should not be overlooked.

Decline pattern and dietary risk assessment of spinetoram in grapes under Egyptian field conditions.

Spinetoram is one of the most extensively used insecticides globally and is a new spinosyn-based insecticide registered for direct treatment of Egyptian grapes. This work established and validated a developed method for determining spinetoram in grape berries and leaves using the QuEChERS coupled LC-MS/MS technique. The average recoveries ranged between 98.52-101.19% and 100.53-104.93%, with RSDs of 2.74-6.21% and 2.79-7.26% for grape berries and leaves, respectively. Spinetoram residues degraded in grape berries and leaves through a first-order kinetic, with an estimated half-life (t1/2) of 4.3 and 2.8 days in grape berries and leaves, respectively, and significant degradation (91.4-97.5%, respectively) after 14 days. Besides, the terminal residues of spinetoram detected in grape berries and leaves samples ranged between 0.017-0.077 mg‧kg-1 and 0.79-0.023 mg·kg-1, respectively, when applied two to three times at a single recommended rate, while it was varied between 0.026-0.44mg‧kg-1 and 0.79-0.023mg‧kg-1 when applied two to three times at a double recommended rate, respectively. A dietary risk assessment was conducted using scientific data from field trials, acceptable daily intake (ADI), and food consumption. It was determined that no noteworthy health hazards were connected to eating grape berries and leaves that had been treated with spinetoram since the risk quotients (RQs) were ≤ 0.4.

High speed enrichment of benzoylurea insecticides by hierarchical pore nitrogen doped carbon materials induced with hydrogen-bonded organic frameworks.

The high speed enrichment of benzoylurea insecticides (BUs) in complex matrices is an essential and challenging step. The present study focuses on the synthesis of a hierarchical pore nitrogen-doped carbon material for magnetic solid phase extraction (MSPE) of BUs. This material was prepared through the carbonization of a composite material ZIF-67@MCA which assembly with hydrogen-bonded organic frameworks (melamine-cyanurate, MCA) and zeolitic imidazolate framework (ZIF-67) at room temperature. The optimal adsorption effect is achieved when the mass ratio of ZIF-67 to MCA is 1/3, and the carbonization was performed at 600 °C, the such obtained carbon material was denoted as 1/3ZIF-67@MCA-DCs-600. The material was characterized with various physical methods including X-ray diffractometry (XRD), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), vibrating sample magnetometer (VSM), water contact angle measurement, Raman spectrometry. 1/3ZIF-67@MCA-DCs-600 exhibits a macro-mesoporous 3D structure with a high degree of nitrogen doping and relatively large specific surface area, making it suitable for magnetic solid phase extraction (MSPE). The adsorption of BUs with concentration of 100 ng mL-1 can reach equilibrium within 5 s. The interaction between BUs and the adsorbent, facilitated by π-π stacking, hydrophobic interactions, hydrogen bonding forces, as well as the material's porosity, enables efficient extraction recoveries ranging from 45 % to 92 %. The enrichment of BUs was achieved through the establishment of an MSPE method under optimized conditions, which was further coupled with high performance liquid chromatography (HPLC) for the determination of the four BUs. The linear range spans from 5 ng ml-1 to 1000 ng ml-1 with the correlation coefficient (R2) of ≥ 0.99, Meanwhile, the detection limit for these four BUs falls within the range of 0.01 to 0.10 ng ml-1. The material exhibits good reusability and can be reused for at least 5 cycles. Inter day and intra-day precision ranges from 2.1-7.9 % and 1.0-5.4 %, respectively. The method demonstrates a high level of reliability in practical applications for the determination of BUs.

Dissipation pattern and dietary risk assessment of chlorfenapyr and methomyl in corn under Egyptian field conditions.

Corn is the second most widely farmed grain for human consumption. Low corn productivity due to damage caused by pests has led to using pesticides to control pest infestations. However, the uncontrolled application of pesticides on corn harms both environmental and human health. Accordingly, field experiments followed good agricultural practices to investigate the dissipation pattern and terminal residues of chlorfenapyr and methomyl in corn and compare the values with established safety limits. Gas chromatography-tandem mass spectrometer coupled with the quick, easy, cheap, effective, rugged, and safe technique was used to analyze residues of chlorfenapyr and methomyl in corn. The average recoveries varied from 94% to 105%, with relative standard deviations (RSDs) of 8%-13% for chlorfenapyr and from 99% to 111%, with RSDs of 10-16% for methomyl. Chlorfenapyr and methomyl residues degraded in corn following a first-order kinetic model, with an estimated half-life (t1/2) of 3.9 and 2.8 days, respectively, and significant degradation (91.4%-98.1.5%, respectively) after 14 days. Although the maximum residue limits of chlorfenapyr and methomyl for corn are yet to be formulated in Egypt, the long-term dietary risk for those pesticides was acceptable, with arisk quotient < 100%, according to the national assessments. These findings are required to guide the correct and safe application of these insecticides in Egypt.

Neonicotinoids as emerging contaminants in China's environment: a review of current data.

Neonicotinoids (NEOs), the most widely used class of insecticides, are pervasive in the environment, eliciting concerns due to their hydrophilicity, persistence, and potential ecological risks. As the leading pesticide consumer, China shows significant regional disparities in NEO contamination. This review explores NEO distribution, sources, and toxic risks across China. The primary NEO pollutants identified in environmental samples include imidacloprid, thiamethoxam, and acetamiprid. In the north, corn cultivation represents the principal source of NEOs during wet seasons, while rice dominates in the south year-round. The high concentration levels of NEOs have been detected in the aquatic environment in the southern regions (130.25 ng/L), the urban river Sects. (157.66 ng/L), and the downstream sections of the Yangtze River (58.9 ng/L), indicating that climate conditions and urban pollution emissions are important drivers of water pollution. Neonicotinoids were detected at higher levels in agricultural soils compared to other soil types, with southern agricultural areas showing higher concentrations (average 27.21 ng/g) than northern regions (average 12.77 ng/g). Atmospheric NEO levels were lower, with the highest concentration at 1560 pg/m3. The levels of total neonicotinoid pesticides in aquatic environments across China predominantly exceed the chronic toxicity ecological threshold of 35 ng/L, particularly in the regions of Beijing and the Qilu Lake Basin, where they likely exceed the acute toxicity ecological threshold of 200 ng/L. In the future, efforts should focus on neonicotinoid distribution in agriculturally developed regions of Southwest China, while also emphasizing their usage in urban greening and household settings.

Sulfoxaflor residues and exposure risk assessment in grape under Egyptian field conditions.

Grapes are among the most popular fruits globally, and insecticides are commonly used on grape farms. Sulfoxaflor, a novel sulfoximine insecticide that works against various insect pests, is extensively used in Egypt. Our field trials assessed the dynamics and final residues of sulfoxaflor in grapes and grape leaves grown in Egyptian environments with different application rates, including worst-case scenarios. A QuEChERS-based method with LC-MS/MS was used to analyze residues of sulfoxaflor in grapes and grape leaves. The limit of quantification (LOQ) was validated at 0.01 mg‧kg-1. Sulfoxaflor residues are degraded in grapes and grape leaves according to a first-order kinetic model, with an estimated half-life (t1/2) of 7.04 and 7.7 days, respectively, and considerable degradation (74.68 and 72.16%, respectively) after 14 days. The final residues in grapes and grape leaves were below the Codex or EU maximum residue limit (MRL) (2 mg‧kg-1) after 3 days of the recommended and high application rates. The findings showed that grapes and leaves treated with sulfoxaflor at the recommended rate are safe for humans 3 days after two or three consecutive treatments with intervals of 14 days. The current study should pave the way for implementing safe and appropriate sulfoxaflor use in grapes and grape leaves in Egypt.

Milkweed in agricultural field margins - A neonicotinoid exposure route for pollinators at multiple life stages.

Neonicotinoid insecticides move from targeted crops to wildflowers located in adjacent field margins, acting as a potential exposure source for wild pollinators and insect species of conservation concern, including monarch butterflies. Monarchs rely on milkweed over multiple life stages, including as a host plant for eggs and a food source for both larvae (leaves) and adults (flowers). Milkweeds, which are closely associated with field margins, can contain neonicotinoid residues, but previous assessments are constrained to a single plant tissue type. In 2017 and 2018, we sampled milkweeds from 95 field margins adjacent to crop fields (corn, soybean, hay, wheat, and barley) in agricultural landscapes of eastern Ontario, Canada. Milkweeds were sampled during the flower blooming period and leaves and flower tissues were analysed. The neonicotinoids acetamiprid, clothianidin, thiamethoxam, and thiacloprid were detected. Maximum concentrations in leaf samples included 10.30 ng/g of clothianidin in 2017, and 24.4 ng/g of thiamethoxam in 2018. Clothianidin and thiamethoxam percent detections in flowers (72 % and 61 %, respectively) were significantly higher than detections in leaves (24 % and 31 %, respectively). Thiamethoxam concentrations were significantly higher in paired flower samples than leaf samples (median 0.33 ng/g vs <0.07 ng/g) while clothianidin concentrations also trended higher in flowers (median 0.18-0.55 ng/g vs <0.18 ng/g). Only thiamethoxam showed significant differences between years, and we found no effect of crop type, with hay, soybean and corn fields all yielding 50-56 % detections in leaves. We found significantly higher concentrations in older milkweed flowers than young flowers or leaves (medians 0.87 ng/g vs <0.18 ng/g and 0.45 ng/g vs <0.07 ng/g for clothianidin and thiamethoxam, respectively). Our results highlight the importance of considering variation in milkweed tissue type and age of flowers in neonicotinoid exposure risk assessments. Efforts to increase milkweed availability in agricultural landscapes should consider how exposure to neonicotinoids can be mitigated.

Establishment of a rapid and sensitive ic-ELISA for the detection of thiacloprid residues in honey and medicinal herbs using a novel highly specific monoclonal antibody.

Thiacloprid is one of the first generation of neonicotinoid insecticide with a chloropyridine structure like imidacloprid and acetamiprid. Recent studies have revealed its environmental and non-target organism toxicity, leading to restrictions on its use in many countries and regions. Despite limitations, thiacloprid has been detected in various environmental samples, food sources, and biological specimens, posing a significant threat to human health, necessitating advanced detection methods for monitoring. In this study, a highly specific monoclonal antibody against thiacloprid via a multi-immunogen strategy was prepared and a rapid and sensitive enzyme-linked immunosorbent assay for the detection of thiacloprid residues in honey and medicinal herbs was established. The half maximal inhibitory concentration (IC50) of this method was 0.38 ng/mL, improving the sensitivity by 1.2-480.6 times compared to existing reports, and the limit of detection (IC20) was 0.097 ng/mL. The method was successfully applied to the determination of thiacloprid residues in honey and medicinal herbs (Crataegi fructus, Citri reticulatae pericarpium), achieving recovery rates ranging from 87.50 % to 116.11 %. The obtained results were verified using the LC-MS/MS method. The multi-immunogen strategy proposed in this study provides an approach for the preparation of highly sensitive and specific monoclonal antibodies, and immunoassay established based on it has good application prospects in complex matrices.

A smartphone-based supramolecular biosensor for portable and rapid detection of buprofezin in real food samples.

Buprofezin (BUP) is an insect growth regulator widely used in agriculture to control hemipteran pests, particularly the melon aphid, Aphis gossypii, due to its efficiency and low toxicity. Although approved by the Chinese government, its maximum residue limit (MRL) in food is strictly regulated, and conventional techniques for detecting BUP have several limitations. Our study reports successful BUP detection using a supramolecular fluorescent probe DP@ALB, constructed with chalcone-based fluorescent dye DP and albumin as the host. The probe offers advantages such as low cost, visual signal output with high fluorescence color variation, rapid response, and high sensitivity. Additionally, portable test strips enable convenient on-site BUP detection and simplifying field monitoring of spiked real samples. The study achieves precise qualitative and quantitative BUP analysis in grape fruit, groundwater, and soil with satisfactory recoveries. Further, the biological applicability of sensor for the in vitro detection of BUP in L929 living cells was demonstrated. This research breakthrough overcomes the limitations of traditional analytical methods, offering an efficient and reliable approach for food and environmental monitoring and pesticide residue detection.

Comparison of prenatal and postnatal exposure to neonicotinoids and their temporal trends in breast milk.

Although the potential effects of neonicotinoids (NEOs) in early life have received considerable attention, data on the exposure of mothers and infants to NEOs are scarce. In this study, four parent NEOs and one metabolite were widely detected in paired maternal serum (MS), umbilical cord serum (UCS) and breast milk (BM) samples, with median total NEO concentrations (ΣNEOs) of 113, 160 and 69 ng/L, respectively. Decreasing trends were observed for N-desmethyl-acetamiprid (30 %/year), acetamiprid (22 %/year) and ΣNEOs (15 %/year) in breast milk between 2014 and 2022, whereas increasing trends were seen for clothianidin (17 %/year) and thiamethoxam (30 %/year). N-desmethyl-acetamiprid was the predominant compound in all matrices. However, the contributions of N-desmethyl-acetamiprid (35 %) and thiamethoxam (36 %) in breast milk were similar in 2022. Moreover, thiamethoxam has become the predominant contributor to the estimated daily intake of ΣNEOs since 2018, with the highest contribution of 71 % in 2022, suggesting the effects of NEOs continue to evolve and more attention should be paid to the new NEOs. Notably, the correlations and ratios of NEOs between paired UCS and MS were more significant and higher than those between paired BM and MS, respectively, indicating that NEO exposure was largely affected by the prenatal period.

Comparison of different fast gas chromatography - mass spectrometry techniques (Cold EI, MS/MS, and HRMS) for the analysis of pyrethroid insecticide residues in food.

In the multiclass, multiresidue analysis of pesticides in food and environmental samples, pyrethroid insecticides are generally more difficult to analyze than other types of analytes. They do not ionize well by electrospray ionization, and although they are suitable for analysis by gas chromatography-mass spectrometry (GC-MS), selectivity using standard electron ionization (EI) in GC-MS is often insufficient because the molecular ion is rarely present. Many pyrethroids tend to have the same fragment ions in MS or high-resolution (HR)MS, and similar ion transitions in tandem MS/MS, leading to difficulties in distinguishing different pyrethroids from each other and chemical interferences in complex matrices. In this study, different forms of fast GC coupled with different types of MS detectors were compared for the analysis of up to 15 pyrethroids in barley extracts as a test case to assess which approach was the most advantageous. The three studied GC-MS techniques consisted of Cold EI using supersonic molecular beams in selected ion monitoring (SIM) mode with a single quadrupole instrument; triple quadrupole MS/MS; and HRMS using an orbital ion trap (orbitrap). A higher flow rate was used in Cold EI, and low pressure (LP) GC was employed in the MS/MS and orbitrap methods, to speed up the GC analyses (<10 min chromatograms in all cases). Each technique had some advantages over the others depending on specific pyrethroid analytes in the matrix. Nontargeted LPGC-orbitrap typically yielded the highest selectivity, but it rarely achieved the needed detectability to quantidentify the residues at 10 ng g-1. Cold EI-SIM and LPGC-MS/MS usually met the needed detection limits and generally achieved similar capabilities for the targeted pyrethroids.

Spatiotemporal distribution, risk levels, and transport variations in neonicotinoids and fipronil and its metabolites cross a river-to-sea continuum.

Neonicotinoids (NEOs) and fipronil are widely used in pest control, but their spatiotemporal distribution and risk levels in the "river-estuary-bay" system remain unclear. Between 2018 and 2021, 148 water samples from rivers to inshore and offshore seawater in Laizhou Bay, China were collected to investigate the presence of eight NEOs and fipronil and its metabolites (FIPs). Significant seasonal variations in NEOs were observed under the influence of different cultivation practices and climatic conditions, with higher levels in the summer than in the spring. The average concentrations of total neonicotinoids (ΣNEOs) and ∑FIPs decreased from rivers (63.64 ng/L, 2.41 ng/L) to inshore (22.62 ng/L, 0.14 ng/L) and offshore (4.48 ng/L, 0.10 ng/L) seawater of Laizhou Bay. The average concentrations of ΣNEOs decreased by 85.3 % from 2018 to 2021. The predominant insecticides in the study area were acetamiprid, thiamethoxam, imidacloprid, and fipronil sulfone, with a gradual shift toward low-toxicity and environmentally friendly species over time. Influenced by agricultural intensity, ∑NEOs were mostly distributed in the Yellow River, Xiaoqing River, and their estuaries, where they pose chronic ecological risks. However, FIP exhibited high risk in certain rivers and sewage treatment plants owing to the use of animal repellents or landscape gardening insecticides. This study provides evidence of the transfer of NEOs and FIPs from rivers to the ocean and also clarifies their transition dynamics and changes in risk levels from rivers to oceans. Additionally, the study offers data support for identifying critical pesticide control areas.

Fluorometric detection of copper and imidacloprid using nitrogen-doped graphitic carbon dots: A promising method for environmental monitoring.

Pesticides in environmental samples pose significant risks to ecosystems and human health since they require precise and efficient detection methods. Imidacloprid (IMI), a widely used neonicotinoid insecticide, exemplifies these hazards due to its potential toxicity. This study addresses the urgent need for improved monitoring of such contaminants by introducing a novel fluorometric method for detecting IMI using nitrogen-doped graphite carbon dots (N-GCDs). The sensor operates by quenching fluorescence through the interaction of Cu2+ ions with N-GCDs. Subsequently, IMI binds to the imidazole group, chelates with Cu2+, and restores the fluorescence of N-GCDs. This alternating fluorescence behavior allows for the accurate identification of both Cu2+ and IMI. The sensor exhibits linear detection ranges of 20-100 nM for Cu2+ and 10-140 µg/L for IMI, with detection limits of 18 nM and 1.2 µg/L, respectively. The high sensitivity of this sensor enables the detection of real-world samples, which underscores its potential for practical use in environmental monitoring and agricultural safety.