Residual pesticides in soil may be taken in by plants and thus have a risk for plant growth and food safety. In this study, uptake of triadimefon and its subsequent translocation and accumulation ...were investigated with wheat as model plants. The results from hydroponics indicated that triadimefon was absorbed by wheat roots mainly through apoplastic pathway and predominantly distributed into the water soluble fractions (66.7−76.0%). After being uptaken by roots, triadimefon was easily translocated upward to wheat shoots and leaves. Interestingly, triadimefon in leaves was mainly distributed in the soluble fraction by 52.5% at the beginning, and gradually transferred into the cell wall by 47.2% at equilibrium. The uptake of triadimefon from soils by wheat plants was similar to that in hydroponics. Its accumulation were mainly governed by adsorption of the fungicide onto soils, and positively correlated with its concentration in in situ pore water (CIPW). Thus, CIPW can be suitable for predicting the uptake of triadimefon by wheat from soils. Accordingly, uptake of triadimefon by wheat was predicted well by using the partition-limited model. Our study provides valuable information for guiding the practical application and safety evaluation of triadimefon.
Display omitted
•Triadimefon could be easily translocated upward to wheat leaves.•The subcellular distribution of triadimefon affected its translocation capacity.•Apoplastic pathways contributed to the uptake of triadimefon by wheat roots.•Concentration of triadimefon in in situ pore water can predict its uptake by wheat.
•A multiplex fluorescence immunoassay for organophosphate pesticides analysis was developed.•AuNPs probes were constructed with antibodies and oligonucleotides to amplify the signal.•Multiple ...chemical residues analysis can be done in a single well.•The method shows a high sensitivity and a good precision.•The method can provide a reference for multi-residue analysis of small molecule contaminants.
Herein, we developed a multi-analyte fluorescence immunoassay for detection of three organophosphate pesticides (triazophos, parathion, and chlorpyrifos) in various agro-products (rice, wheat, cucumber, cabbage, and apple) using fluorescently labeled oligonucleotide and gold nanoparticle (AuNP) signal amplification technology. The AuNP probes for the three analytes were constructed by simultaneously modifying the corresponding antibodies and fluorescently labeled oligonucleotides on the probe surface. Three fluorophores (6-FAM, Cy3, and Texas red) with high fluorescence intensity and little overlap of excitation/emission wavelengths were selected. The method showed satisfactory linearity for triazophos, parathion, and chlorpyrifos in the ranges of 0.01–20, 0.05–50, and 0.5–1000 μg/L, respectively. For the 3 analytes, the limits of detection (LODs) were 0.007, 0.009, and 0.087 μg/L, respectively. The average recoveries were 77.7–113.6%, with relative standard deviations (RSDs) of 7.1–17.1% in various food matrices. The proposed method offers great potential in food safety surveillance, and could be used as well as a reference for multi-residue analysis of other small-molecule contaminants.
Food safety is as important as ever, and the safeguards implemented to inspect and reduce pesticides, veterinary drugs, toxins, pathogens, illegal additives, and other deleterious contaminants in our ...food supply has helped improve human health and increase the length and quality of our lives ....
An electrochemical sensor based on molecularly imprinted polypyrrole (MIPPy) was developed for selective and sensitive detection of the herbicide glyphosate (Gly) in cucumber and tap water samples. ...The sensor was prepared via synthesis of molecularly imprinted polymers on a gold electrode in the presence of Gly as the template molecule and pyrrole as the functional monomer by cyclic voltammetry (CV). The sensor preparation conditions including the ratio of template to functional monomers, number of CV cycles in the electropolymerization process, the method of template removal, incubation time, and pH were optimized. Under the optimal experimental conditions, the DPV peak currents of hexacyanoferrate/hexacyanoferrite changed linearly with Gly concentration in the range from 5 to 800 ng mL
−1
, with a detection limit of 0.27 ng mL
−1
(
S/N
= 3). The sensor was used to detect the concentration of Gly in cucumber and tap water samples, with recoveries ranging from 72.70 to 98.96%. The proposed sensor showed excellent selectivity, good stability and reversibility, and could detect the Gly in real samples rapidly and sensitively.
Graphical abstract
Schematic illustration of the experimental procedure to detect Gly using the MIPPy electrode
Display omitted
•The review systematically and completely collated the enzyme inhibition method based on Au nanomaterials for organophosphorus pesticide detection method in the last 20 years.•The ...significance of the optical properties of Au nanomaterials is outlined with different shapes, sizes, and surface modifiers in enzyme inhibition methods.•The principles, classification and application of enzyme inhibition methods based on Au nanomaterials are comprehensively summarized from a new perspective in agricultural and environmental samples, including colorimetric method, fluorometric method, electrochemical biosensor method.•Unlike traditional enzyme inhibition method, the merits of enzyme inhibition method based on Au nanomaterials were elaborated in this review.•Combined with the research progress of enzyme inhibition method, this review predicts the future research direction of enzyme inhibition method, providing a theoretical reference for researchers.
Organophosphorus pesticides (OPs), as insecticides or acaricides, are widely used in agricultural products to ensure agricultural production. However, widespread use of OPs leads to environmental contamination and significant negative consequences on biodiversity, food security, and water resources. Therefore, developing a sensitive and rapid method to determine OPs residues in different matrices is necessary. Originally, the enzyme inhibition methods are often used as preliminary screens of OPs in crops. Many studies on the characteristic of Au nanomaterials have constantly been emerging in the past decade. Combined with anisotropic Au nanomaterials, enzyme inhibition methods have the advantages of high sensitivity, durability, and high stability.
This review aims to summarize the principles and strategies of gold (Au) nanomaterials in enzyme inhibition methods, including colorimetric (dispersion, particle size of Au nanomaterials) and fluorometric (fluorescence energy transfer, internal filtration effect) detection, and electrochemical sensing system (shape of Au nanomaterials, Au nanomaterials combined with other nanomaterials). The application of enzyme inhibition in agricultural products and research progress was also outlined. Next, this review illustrates the advantages of Au nanomaterial-based enzyme inhibition methods compared with conventional enzyme inhibition methods. The detection limits and linear range of colorimetric and fluorometric detection and electrochemical biosensors have also been provided. At last, key perspectives, trends, gaps, and future research directions are proposed.
Herein, we introduced the technology of enzyme inhibition method based on Au nanomaterials for onsite and infield rapid detection of organophosphorus pesticide.
An effective method using liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed and optimized to obtain a complete separation of five representative plant growth regulators (PGRs) ...gibberellic acid, 2,4-dichlorophenoxyacetic acid (2,4-D), thidiazuron, forchlorfenuron, and paclobutrazol in fruits. Extraction was performed with acetonitrile containing 0.1% (v/v) acetic acid, applying modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) methodology. LC–MS/MS conditions including composition of mobile phases and mass spectrometry (MS) conditions were evaluated to achieve the highest sensitivity in MS detection. All of the data acquisition was employed in the segmented multiple-reaction monitoring mode for the selected negative and positive transition ions. The octadecylsilyl (C18) dispersive solid-phase extraction (SPE) sorbent was found to provide the more satisfied recoveries than primary secondary amine (PSA) and graphitized carbon black (GCB) for five target PGRs. The optimized method allowed for recoveries of 76–112% for the five PGRs from fruit samples with relative standard deviation (RSD) values less than 10%. Limits of quantification (0.5–16.5 μg/kg) were lower than the maximum limit of residues established for PGRs. The results demonstrated that the developed LC–MS/MS and QuEChERS extraction method is highly effective for analyzing trace amounts of target PGRs in fruit samples. Finally, the method was successfully used to detect residual PGRs in Beijing, China, in 2010. The concentrations of 2,4-D (5.1–1503 μg/kg) and paclobutrazol (1–1381 μg/kg) found in orange and peach, respectively, suggesting that the use of these PGRs in these fruits should be regulated in China in the future.
Magnetic zeolitic imidazolate framework 67/graphene oxide composites were synthesized by one‐pot method at room temperature for the first time. Electrostatic interactions between positively charged ...metal ions and both negatively charged graphene oxide and Fe3O4 nanoparticles were expected to chemically stabilize magnetic composites to generate homogeneous magnetic products. The additional amount of graphene oxide and stirring time of graphene oxide, Co2+, and Fe3O4 solution were investigated. The zeolitic imidazolate framework 67 and Fe3O4 nanoparticles were uniformly attached on the surface of graphene oxide. The composites were applied to magnetic solid‐phase extraction of five neonicotinoid insecticides in environmental water samples. The main experimental parameters such as amount of added magnetic composites, extraction pH, ionic strength, and desorption solvent were optimized to increase the capacity of adsorbing neonicotinoid insecticides. The results show limits of detection at signal‐to‐noise ratio of 3 were 0.06–1.0 ng/mL under optimal conditions. All analytes exhibited good linearity with correlation coefficients of higher than 0.9915. The relative standard deviations for five neonicotinoid insecticides in environmental samples ranged from 1.8 to 16.5%, and good recoveries from 83.5 to 117.0% were obtained, indicating that magnetic zeolitic imidazolate framework 67/graphene oxide composites were feasible for analysis of trace analytes in environmental water samples.
A rapid detection method is introduced for residual trace levels of triazophos in water and agricultural products using an immunoassay based on catalytic hairpin self-assembly (CHA). The gold ...nanoparticle (AuNPs) surface was modified with triazophos antibody and sulfhydryl bio-barcode, and an immune competition reaction system was established between triazophos and its ovalbumin-hapten (OVA-hapten). The bio-barcode served as a catalyst to continuously induce the CHA reaction to achieve the dual signal amplification. The method does not rely on the participation of enzymes, and the addition of fluorescent materials in the last step avoids interfering factors, such as a fluorescence burst. The emitted fluorescence was detected at 489/521 nm excitation/emission wavelengths. The detection range of the developed method was 0.01–50 ng/mL for triazophos, and the limit of detection (LOD) was 0.0048 ng/mL. The developed method correlates well with the results obtained by LC–MS/MS, with satisfactory recovery and sensitivity. In sum, the designed method is reliable and provides a new approach to detect pesticide residues rapidly and quantitatively.
Graphical Abstract
A luminol-H2O2-HRP chemiluminescence system with high relative luminescent intensity (RLU) and long stabilization time was investigated. First, the comparative study on the enhancement effect of ten ...compounds as enhancers to the luminol-H2O2-HRP chemiluminescence system was carried out, and the results showed that 4-(imidazol-1-yl)phenol (4-IMP), 4-iodophenol (4-IOP), 4-bromophenol (4-BOP) and 4-hydroxy-4'-iodobiphenyl (HIOP) had the best performance. Based on the experiment, the four enhancers were dissolved in acetone, acetonitrile, methanol, and dimethylformamide (DMF) with various concentrations, the results indicated that 4-IMP, 4-IOP, 4-BOP and HIOP dissolved in DMF with the concentrations of 0.2%, 3.2%, 1.6% and 3.2% could get the highest RLU values. Subsequently, the influences of pH, ionic strength, HRP, 4-IMP, 4-IOP, 4-BOP, HIOP, H2O2 and luminol on the stabilization of the luminol-H2O2-HRP chemiluminescence system were studied, and we found that pH value, ionic strength, 4-IMP, 4-IOP, 4-BOP, HIOP, H2O2 and luminol have little influence on luminescent stabilization, while HRP has a great influence. In different ranges of HRP concentration, different enhancers should be selected. When the concentration is within the range of 0~6 ng/mL, 4-IMP should be selected. When the concentration of HRP ranges from 6 to 25 ng/mL, 4-IOP was the best choice. And when the concentration is within the range of 25~80 ng/mL, HIOP should be selected as the enhancer. Finally, the three well-performing chemiluminescent enhanced solutions (CESs) have been further optimized according to the three enhancers (4-IMP, 4-IOP and HIOP) in their utilized HRP concentration ranges.
UIO-66 crystals were explored for the first time to adsorb neonicotinoid insecticides in environmental water samples. HPLC coupled with tandem MS was used for quantification and determination of ...neonicotinoid insecticides. UiO-66 crystals was successfully synthesized by a simple constant-temperature bath method. Synthesized UiO-66 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry and nitrogen adsorption porosimetry (NAP), which demonstrated a uniform particle size, a large Brunauer–Emmett–Teller (BET) surface area and high thermostability. The adsorbing results showed that UIO-66 crystals could be used as a promising adsorbents for rapid extraction of neonicotinoid insecticides and be reused at least 10 times. Under the optimized conditions, the limits of detection (LODs, S/N = 3) and limits of quantification (LOQs, S/N = 10) for the five insecticides were found to be 0.02–0.4 ng/mL and 0.05–1.0 ng/mL, respectively. This developed approach not only provided more simple and sensitive method, as well as possessing satisfactory recovery for neonicotinoid insecticides, but also for other traces in environmental samples.
PDF
