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Analytical and Bioanalytical Chemistry May 2021The long-term consumption of food with pesticide residues has harmful effects on human health and the demand for pesticide detection technology tends to be miniaturized...
The long-term consumption of food with pesticide residues has harmful effects on human health and the demand for pesticide detection technology tends to be miniaturized and instant. To this end, we demonstrated the first application of indirectly detecting two carbamate pesticides, metolcarb and carbaryl, by gold nanoparticle-modified indium tin oxide electrode in dual-channel microchip electrophoresis and amperometric detection (ME-AD) system. m-Cresol and α-naphthol were obtained after pesticide hydrolysis in alkaline solution, and then separated and detected by ME-AD. Parameters including the detection potential and running buffer concentration and pH were optimized to improve the detection sensitivity and separation efficiency. Under the optimal conditions, the two analytes were completely separated within 80 s. m-Cresol and α-naphthol presented a wide linear range from 1 to 100 μM, with limits of detection of 0.16 μM and 0.34 μM, respectively (S/N = 3). Moreover, the reliability of this system was demonstrated by analyzing metolcarb and carbaryl in spiked vegetable samples.
Topics: Carbamates; Electrochemical Techniques; Electrophoresis, Microchip; Limit of Detection; Pesticide Residues; Reference Standards; Reproducibility of Results; Vegetables
PubMed: 33635387
DOI: 10.1007/s00216-021-03237-3 -
Bioorganic & Medicinal Chemistry Jun 2019A series of new doramectin derivatives containing carbamate, ester and sulfonate were synthesized, and their structures were characterized by H and C nuclear magnetic...
A series of new doramectin derivatives containing carbamate, ester and sulfonate were synthesized, and their structures were characterized by H and C nuclear magnetic resonance (NMR) and high-resolution mass spectrum (HRMS). Their insecticidal activities against oriental armyworm, diamondback moth, and corn borer were evaluated and compared with the parent doramectin and commercial avermectins, metolcarb, fenpropathrin. Among all compounds, three compounds (3a, 3g and 3h) showed excellent insecticidal effect. In particular, compound 3g containing cyclopropyl carbamate against oriental armyworm, diamondback moth, and corn borer, exhibited the most promising insecticidal activity with the final mortality rate of 66.67%, 36.67%, 40.00% at the concentration of 12.5 mg/L, respectively. The LC values of 3g were 5.8859, 22.3214, and 22.0205 mg/L, showing 6.74, 2.23, 2.21-fold higher potency than parent doramectin (LC values of 39.6907, 49.7736, and 48.6129 mg/L) and 6.83, 1.93, 3.36-fold higher potency than commercial avermectins (LC values of 40.2489, 42.9922, and 73.9508 mg/L). Additionally, molecular docking simulations revealed that 3g displayed stronger hydrogen-bonding action in binding with the GABA receptor than parent doramectin, which were crucial for keeping high insecticidal activity. The present work demonstrated that these compounds containing alkyl carbamate group could be considered as potential candidates for the development of novel pesticides in the future.
Topics: Animals; Binding Sites; Drug Design; Insecticides; Ivermectin; Molecular Docking Simulation; Molecular Structure; Moths; Phenylcarbamates; Pyrethrins; Receptors, GABA; Structure-Activity Relationship
PubMed: 30626556
DOI: 10.1016/j.bmc.2018.12.040 -
Analytical Methods : Advancing Methods... Aug 2022High-temperature comprehensive two-dimensional gas chromatography (HTGC × GC) using a longitudinally modulated cryogenic system (LMCS) was developed for the analysis of...
High-temperature comprehensive two-dimensional gas chromatography (HTGC × GC) using a longitudinally modulated cryogenic system (LMCS) was developed for the analysis of low-volatility pesticides in cabbage. The method applied DB-17HT and DB-5HT as the first and second dimensional (D and D) columns, respectively. Twelve pesticides, namely 6 organochlorines (4,4'-DDT, β-endosulfan, endosulfan sulfate, endrin, heptachlor, and dicofol), 4 carbamates (metolcarb, isoprocarb, methiocarb, and carbofuran), 1 organophosphate (chlorpyrifos), and 1 pyrethroid (permethrin), were spiked into cabbage samples and prepared using QuEChERS. The applied oven temperature was up to 340 °C, enabling the elution of all the target pesticides and the matrix. The effects of initial oven temperature program, temperature ramp rate, LMCS trap temperature, and modulation period () on the separation results were investigated, leading to the suitable conditions of 80 °C, 15 °C min, 10 °C, and 12 s, respectively. The method detection limits, signal-to-noise ratio, and recoveries of the compounds were within the ranges of 0.01-0.09 mg kg, 4.26-32.7, and 78-104%, respectively. Good linearity ranges within the concentration range of 0.1-1 ppm with > 0.9134 were also obtained with the intra and interday precisions of the peak areas of 0.4-9.8% and 1.0-10.2%, respectively.
Topics: Brassica; Chromatography, Gas; Hydrocarbons, Chlorinated; Pesticides; Temperature
PubMed: 35929731
DOI: 10.1039/d2ay00998f -
Biosensors & Bioelectronics May 2016A novel approach to synthesize molecularly imprinted polymer (MIP) nanoparticles using a MIL-101 support (a type of metal-organic framework) is reported herein for the...
A novel approach to synthesize molecularly imprinted polymer (MIP) nanoparticles using a MIL-101 support (a type of metal-organic framework) is reported herein for the first time; the sample is referred as MIL@MIP. The nanoparticles were well distributed within the polymer film, and exhibit an octahedral shape, satisfied thermal stability, and a high specific surface area (SSA) of 1579.43 m(2)g(-1). The adsorption behavior of MIL@MIP toward metolcarb in aqueous solution was subsequently examined. The synthesized MIL@MIP displayed satisfactory high transfer mass rates and a high selective adsorption affinity for metolcarb. Based on these results, a quartz crystal microbalance (QCM) sensor based on MIL@MIP was subsequently constructed and examined for the sensitive detection of metolcarb. Under optimal conditions, the detection limit of the system assessed in pear juice was 0.0689 mg L(-1) within a linear concentration range of 0.1-0.9 mg L(-1). MIL@MIP-QCM system combines the advantages of MIL-101 and molecularly imprinted technology (MIT), thereby achieving high detection sensitivity and selectivity. The current findings suggest the potential of MIL@MIP for detecting trace level pesticides and veterinary drugs for food safety and environmental control.
Topics: Adsorption; Biosensing Techniques; Coordination Complexes; Limit of Detection; Metal-Organic Frameworks; Metals; Molecular Imprinting; Nanoparticles; Pesticides; Phenylcarbamates; Polymers; Quartz Crystal Microbalance Techniques
PubMed: 26735869
DOI: 10.1016/j.bios.2015.12.071 -
Biosensors & Bioelectronics Feb 2015In this work, we presented a three-dimensional (3D) molecularly imprinted electrochemical sensor (MIECS) with novel strategy for ultrasensitive and specific...
Prussian blue mediated amplification combined with signal enhancement of ordered mesoporous carbon for ultrasensitive and specific quantification of metolcarb by a three-dimensional molecularly imprinted electrochemical sensor.
In this work, we presented a three-dimensional (3D) molecularly imprinted electrochemical sensor (MIECS) with novel strategy for ultrasensitive and specific quantification of metolcarb based on prussian blue (PB) mediated amplification combined with signal enhancement of ordered mesoporous carbon. The molecularly imprinted polymers were synthesized by electrochemically induced redox polymerization of para aminobenzoic acid (p-ABA) in the presence of template metolcarb. Ordered mesoporous carbon material (CMK-3) was introduced to enhance the electrochemical response by improving the structure of the modified electrodes and facilitating charge transfer processes of PB which was used as an inherent electrochemical active probe. The modification process for the working electrodes of the MIECS was characterized by scanning electron microscope (SEM) and cyclic voltammetry (CV), and several important parameters controlling the performance of the MIECS were investigated and optimized in detail. The MIECS with 3D structure had the advantages of ease of preparation, high porous surface structure, speedy response, ultrasensitivity, selectivity, reliable stability, good reproducibility and repeatability. Under the optimal conditions, the MIECS offered an excellent current response for metolcarb in the linear response range of 5.0 × 10(-10)-1.0 × 10(-4) mol L(-1) and the limit of detection (LOD) was calculated to be 9.3 × 10 (-11)mol L(-1) (S/N = 3). The proposed MIECS has been successfully applied for the determination of metolcarb in real samples with satisfactory recoveries. Furthermore, the construction route of this ultrasensitive 3D MIECS may provide a guideline for the determination of non-electroactive analytes in environmental control and food safety.
Topics: Carbon; Conductometry; Electrodes; Equipment Design; Equipment Failure Analysis; Ferrocyanides; Molecular Imprinting; Pesticides; Phenylcarbamates; Porosity; Reproducibility of Results; Sensitivity and Specificity
PubMed: 25240126
DOI: 10.1016/j.bios.2014.09.009 -
Analytica Chimica Acta Mar 2020We report herein the design of a novel electrochemical sensing strategy for sensitive detection of pesticide based on graphitic carbon nitride (g-CN)/graphene oxide(GO)...
We report herein the design of a novel electrochemical sensing strategy for sensitive detection of pesticide based on graphitic carbon nitride (g-CN)/graphene oxide(GO) nanocomposite covalently bound to a ferrocene containing dendrimer(Fc-TED). The g-CN with sufficient N atoms for providing lone pairs of electrons to an electron acceptor so as to enhance the adsorption towards organic molecules. The Fc-TED dendrimers with the native redox signaling center (Fe/Fe) can increase the electron transition of g-CN from valence to conduction band. While GO can accelerate the electron transfer from g-CN surface and Fc-TED to glassy carbon electrode(GCE), which would amplify the electrochemical signal of g-CN/GO/Fc-TED/GCE sensor and then improve the sensing performance. It is found that the fabricated electrode demonstrated an admirable electrochemical sensing performance towards metolcarb in terms of low detection limit (8.3 nM), wide concentration range (0.045-213 μM) and rapid response time (2s). The proposed sensor can selectively detect the metolcarb and easily discriminated metolcarb from the possible interfering species. The practical applicability of the sensor was successfully evaluated in real vegetable sample and achieved satisfactory recoveries with good precision and accuracy.
Topics: Biosensing Techniques; Dendrimers; Electrochemical Techniques; Electrodes; Ferrous Compounds; Food Contamination; Graphite; Limit of Detection; Metallocenes; Nanocomposites; Nitrogen Compounds; Oxidation-Reduction; Pesticide Residues; Phenylcarbamates; Spinacia oleracea
PubMed: 32081192
DOI: 10.1016/j.aca.2019.12.066 -
Analytical Methods : Advancing Methods... Oct 2022Carbamate (CB) pesticides possess potential carcinogenic and mutagenic activities towards humans even at very low dosages. Thus, broad-specificity probes with high...
Carbamate (CB) pesticides possess potential carcinogenic and mutagenic activities towards humans even at very low dosages. Thus, broad-specificity probes with high sensitivity and speed are needed for multiple CB determination. This study is the first to focus on Dy ions-coordinated self-assembly on a silica core using a surface imprinting procedure, for the simultaneous fluorometric detection of residues of metolcarb (MC) and pirimicarb (PC) insecticides. A simple and mild solvothermal method was applied for the preparation of fluorescent imprinted microspheres starting from 1,10-phenanthroline (Phen)-ligated Dy ions to guide imprinted self-assembly of chitosan (CTS), glutaraldehyde (GA), and two carbamate pesticides (MC and PC) on the silica surface by means of coordinate bonds and hydrogen bonds. The as-prepared microspheres displayed strong fluorescence emissions the antenna effect derived from the Phen ligand and the Schiff base oligomers for sensitizing the Dy ions. An expanded in-depth mechanism study was performed on the fluorescence enhancement involving Förster resonance energy transfer (FRET) from the pesticides (donor) to the acceptor. A linear increase in fluorescence at 483 nm for MC and 574 nm for PC upon the imprinted microspheres was observed under the same 350 nm excitation wavelength. Moreover, the quantitative recognition process could be carried out simultaneously and tolerate strong distractions both from five other similar carbamate insecticides and from complicated matrices (, an extract of Ramat). The detection limit was 4 ng mL with a range of 10-60 ng mL for MC and 0.4 ng mL with a range of 1-30 ng mL for PC. Further characterization of the material, including TEM, SEM, XPS, and FTIR, Raman, and fluorescence spectra, verified that the Dy ions play a decisive role in promoting imprinted self-assembly around the silica core. Hence, a novel polynuclear Ln-organic imprinted probe having high selectivity, stability, and sensitivity for the detection of two carbamate insecticides is presented in this study.
Topics: Humans; Silicon Dioxide; Microspheres; Molecular Imprinting; Insecticides; Pesticides; Carbamates
PubMed: 36197096
DOI: 10.1039/d2ay01269c -
Food Research International (Ottawa,... Apr 2023The honeysuckle was widely appreciated as tea beverage owing to the biological activities and the unique aroma and flavor. It is in urgent requirement to explore the...
Migration behavior and dietary exposure risk assessment of pesticides residues in honeysuckle (Lonicera japonica Thunb.) based on modified QuEChERS method coupled with tandem mass spectrometry.
The honeysuckle was widely appreciated as tea beverage owing to the biological activities and the unique aroma and flavor. It is in urgent requirement to explore the migration behavior and dietary exposure as the pesticide residues would bring about potential risks through honeysuckle intake. The optimized QuEChERS procedure coupled with the HPLC-MS/MS and GC-MS/MS methods were employed to determine 93 pesticide residues of seven classifications including carbamates, pyrethroid, triazoles, neonicotinoids, organophosphorus, organochlorine, and others for 93 honeysuckle samples from four primary production bases. As a result, 86.02% of the samples were contaminated by at least one pesticide. Unexpectedly, the banned pesticide of carbofuran was also identified. The migration behavior of metolcarb was the highest, whereas thiabendazole contributed less risk to the infusion with relative lower transfer rate. Both the chronic and acute exposure yielded low risk for human health with five high risk pesticides of dichlorvos, cyhalothrin, carbofuran, ethomyl, and pyridaben. Besides, this study provides foundation of dietary exposure risk assessment for honeysuckle and other likewise products.
Topics: Humans; Pesticide Residues; Tandem Mass Spectrometry; Lonicera; Carbofuran; Dietary Exposure; Pesticides; Risk Assessment
PubMed: 36914339
DOI: 10.1016/j.foodres.2023.112572 -
Journal of Chromatography. A Aug 2019A solid phase extraction (SPE) method with a porous organic polymer as adsorbent was established for the extraction of five carbamate pesticides (metolcarb, carbaryl,...
A solid phase extraction (SPE) method with a porous organic polymer as adsorbent was established for the extraction of five carbamate pesticides (metolcarb, carbaryl, isoprocarb, bassa and diethofencarb) from milk, white wine and juice samples prior to high performance liquid chromatography-diode array detection. The main factors affecting the SPE were optimized, including sample volume, sample loading rate, sample solution pH, desorption conditions and cartridge reusability. Under the optimal conditions, a good linearity existed in the range from 1.0 to 320.0 ng mL for milk and white wine samples and from 0.5 to 160.0 ng mL for juice sample with the correlation coefficients between 0.9956 and 0.9998. The method recoveries of the carbamates were 82.0%-110.0%. The limits of detection were 0.12-0.40 ng mL for milk and white wine samples, and 0.06-0.20 ng mL for juice sample. The adsorption mechanism of the adsorbent was investigated by the extraction of different types of organic compounds (carbamates, benzoylurea insecticides, endocrine disrupting chemicals and polycyclic aromatic hydrocarbons) with the adsorbent. The results showed that the existence of the hydrogen-bonding between the adsorbent and the analytes is favorable for the adsorption and strong hydrophobicity seems to have an adverse effect.
Topics: Adsorption; Animals; Beverages; Chromatography, High Pressure Liquid; Food Analysis; Fruit and Vegetable Juices; Hydrophobic and Hydrophilic Interactions; Milk; Pesticides; Polymers; Porosity; Solid Phase Extraction; Wine
PubMed: 31010634
DOI: 10.1016/j.chroma.2019.04.031 -
Inorganic Chemistry Jan 2024A multifunctional single-atom nanozyme, denoted as 3D Ni,N-codoped porous carbon (Ni-NPC), was devised that exhibits remarkable adsorption capabilities and a repertoire...
A multifunctional single-atom nanozyme, denoted as 3D Ni,N-codoped porous carbon (Ni-NPC), was devised that exhibits remarkable adsorption capabilities and a repertoire of enzyme mimetic functions (oxidase- and peroxidase-like). These attributes stem from the distinctive mesoporous thin-shell structure and well-dispersed Ni sites. The efficient adsorption capacity of Ni-NPC was assessed with respect to three carbamate pesticides (CMPs): metolcarb, carbaryl, and isoprocarb. Moreover, a colorimetric detection method for CMP was established based on its robust peroxidase-like catalytic activity and sequential catalytic interactions with acetylcholinesterase. Furthermore, a portable colorimetric sensor based on a hydrogel sphere integrated with a smartphone platform was devised. This sensor enables rapid, on-site, and quantitative assessment of CMP, boasting an extraordinarily low detection limit of 1.5 ng mL. Notably, this sensor was successfully applied to the analysis of CMP levels in lake water and vegetable samples (pakchoi and rape), propelling the progress of real-time detection technologies in food and environment monitoring.
Topics: Smartphone; Acetylcholinesterase; Pesticides; Carbamates; Peroxidase; Peroxidases; Colorimetry
PubMed: 38163760
DOI: 10.1021/acs.inorgchem.3c03642