Detection Of Organophosphorus Pesticides Research Articles

Lamellar Ti3C2 MXene composite decorated with platinum-doped MoS2 nanosheets as electrochemical sensing functional platform for highly sensitive analysis of organophosphorus pesticides

Precisely detecting organophosphorus pesticides (OPs) is paramount in upholding human safety and environmental preservation, especially in food safety. Herein, an electrochemical acetylcholinesterase (AChE) sensing platform entrapped in chitosan (Chit) on the glassy carbon electrodes (GCEs) decorated with Pt/MoS2/Ti3C2 MXene (Pt/MoS2/TM) was constructed for the detection of chlorpyrifos. It is worth noting that Pt/MoS2/TM possesses good biocompatibility, remarkable electrical conductivity, environmental stability and large specific surface area. Besides, the heterostructure formed by the composite of TM and MoS2 improves the conductivity and maintains the original structure, which is conducive to improving the electrochemical property. The coordination effect between the individual components enables the even distribution of functional components and enhances the electrochemical performance of the biosensor (AChE-Chit/Pt/MoS2/TM). Under optimal efficiency and sensitivity, the AChE-Chit/Pt/MoS2/TM/GCE sensing platform exerts comparable analytical performance and a wide concentration range of chlorpyrifos from 10−12 to 10−6 M as well as a low limit of detection (4.71 × 10−13 M). Furthermore, the biosensor is utilized to detect OPs concerning three kinds of fruits and vegetables with good feasibility and recoveries (94.81% to 104.0%). This work would provide a new scheme to develop high-sensitivity sensors based on the two-dimensional nanosheet/laminar hybrid structure for practical applications in environmental monitoring and agricultural product detection.

Covalent organic framework-functionalized magnetic MXene nanocomposite for efficient pre-concentration and detection of organophosphorus and organochlorine pesticides in tea samples before gas chromatography–triple quadrupole mass spectrometry analysis

In this study, a hydrophobic covalent organic framework-functionalized magnetic composite (CoFe2O4@Ti3C2@TAPB−TFTA) with a high specific area with 1,3,5-tris(4-aminophenyl)benzene (TAPB) and 2,3,5,6-tetrafluoroterephthalaldehyde (TFTA) was designed and synthesized through Schiff base reaction. An efficient magnetic solid-phase extraction method was established and combined with gas chromatography–triple quadrupole mass spectrometry to sensitively determine 10 organochlorine and organophosphorus pesticides in tea samples. The established method exhibited good linearity in the range of 0.05–120 μg/L and had low limits of detection (0.013–0.018 μg/L). The method was evaluated with tea samples, and the spiked recoveries of pesticides in different tea samples reached satisfactory values of 85.7–96.8%. Moreover, the adsorption of pesticides was spontaneous and followed Redlich–Peterson isotherm and pseudo-second-order kinetic models. These results demonstrate the sensitivity, effectiveness, and reliability of the proposed method for monitoring organochlorine and organophosphorus pesticides in tea samples, providing a preliminary basis for researchers to reasonably design adsorbents for the efficient extraction of pesticides.

A ratiometric fluorescence sensor for detection of organophosphorus pesticides based on enzyme-regulated multifunctional Fe-based metal-organic framework

The residues of organophosphorus pesticides (OPs) are increasing environmental pollution and public health concerns. Thus, the development of simple, convenient and sensitive method for detection of OPs is crucial. Herein, a multifunctional Fe-based MOF with fluorescence, catalytic and adsorption, is synthesized by a simple one-pot hydrothermal method. The ratiometric fluorescence sensor for detection of OPs is constructed by using only one multifunctional sensing material. The NH2-MIL-101(Fe) is able catalyze the o-phenylenediamine (OPD) into 2,3-diaminophenazine (DAP) in the presence of H2O2. The generated DAP can significantly quench the intrinsic fluorescence of NH2-MIL-101(Fe) by the fluorescence resonance energy transfer (FRET) and internal filtration effect (IFE), while producing a new measurable fluorescence. Without immobilization or molecular imprinting, pyrophosphate ion (PPi) can inhibit the peroxidase-like activity of the NH2-MIL-101(Fe) by chelating with Fe3+/Fe2+ redox couple. Moreover, PPi can also be hydrolyzed by alkaline phosphatase (ALP), the presence of OPs inhibits the activity of ALP, resulting in the increase of extra PPi preservation and signal changes of ratiometric fluorescence, the interactions of ALP with different OPs are explored by molecular docking, the OPs (e.g., glyphosate) interact with crucial amino acid residues (Asp, Ser, Ala, Lys and Arg) are indicated. The proposed sensor exhibits excellent detection performance for OPs with the detection limit of 18.7 nM, which provides a promising strategy for detection of OPs.

Highly sensitive turn-on electrochemical sensing of organophosphorus pesticides by integration of homogeneous reaction and heterogeneous catalytic signal amplification

Enzyme-inhibited electrochemical sensor is a promising strategy for detecting organophosphorus pesticides (OPs). However, the poor stability of enzymes and the high oxidation potential of thiocholine signal probe limit their potential applications. To address this issue, an indirect strategy was proposed for highly sensitive and reliable detection of chlorpyrifos by integrating homogeneous reaction and heterogeneous catalysis. In the homogeneous reaction, Hg2+ with low oxidation potential was employed as signal probe for chlorpyrifos detection since its electroactivity can be inhibited by thiocholine, which was the hydrolysate of acetylthiocholine catalyzed by acetylcholinesterase. Additionally, Co,N-doped hollow porous carbon nanocage@carbon nanotubes (Co,N-HPNC@CNT) derived from ZIF-8@ZIF-67 was utilized as high-performance electrode material to amplify the stripping voltammetry signal of Hg2+. Thanks to their synergistic effect, the sensor exhibited outstanding sensing performance, excellent stability and good anti-interference ability. This strategy paves the way for the development of high-performance OP sensors and their application in food safety.

Superior oxidase-mimetic activity of FeCo-NC dual-atom nanozyme for smartphone-based visually colorimetric assay of organophosphorus pesticides.

A colorimetric analysis platformhas been successfully developedbased on FeCo-NC dual-atom nanozyme (FeCo-NC DAzyme) for the detection of organophosphorus pesticides (OPPs). The FeCo-NC DAzyme exhibited exceptional oxidase-like activity (OXD), enabling the catalysis of colorless TMB to form blue oxidized TMB (oxTMB) without the need for H2O2 involvement. By combining acid phosphatase (ACP) hydrolase with FeCo-NC DAzyme, a "FeCo-NC DAzyme + TMB + ACP + SAP" colorimetric system was constructed, which facilitated the rapid detection of malathion. Thechromogenic system was appliedto detect malathion using a smartphone-based app and an auxiliary imaging interferogram device for colorimetric measurements, which have a linear range of 0.05-4.0 µM and a limit of detection (LOD) as low as 15 nM in real samples, comparable to UV-Vis and HPLC-DAD detection methods. Overall, these findings present a novel approach for convenient, rapid, and on-site monitoring of OPPs.

Construction of phosphatase-like COF-OMe@Valine-CeO2 nanozymes for ultrasensitive electrochemical detection of organophosphorus pesticides

Construction of highly-active artificial nanozymes for pesticides detection has great significance of human health and ecological systems. Herein, we have successfully designed a two-step approach to synthesize the TAPB-DMTP-COF (hereafter denoted as COF-OMe, TAPB, 1,3,5-tris(4-aminophenyl)benzene; DMTP, 2,5-dimethoxyterephaldehyde; COF, covalent organic framework)@Valine integrated cerium oxide nanozymes (COF-OMe@Valine-CeO2) with phosphatase-like activities, which can cleave phosphate bonds (PO) of organophosphorus pesticides (OPs) for the formation of electroactive p-nitrophenol (p-NP). In detail, the Ce (IV)/Ce (III) species serve as the active sites to polarize and hydrolyze PO bond in OPs, and the excellent adsorption performance of porous COF-OMe toward OPs could promote the hydrolysis process of PO. Moreover, the efficient charge transfer at the covalent interface of COF-OMe@Valine-CeO2 also contributed to this excellent catalytic process. By virtue of those advantages, the COF-OMe@Valine-CeO2 electrochemical platform was successfully applied in methyl-paraoxon (MP) detection. The resulting electrochemical sensors displayed high sensitivity, a wide linear response range of 0.034–76 μmol/L, and low detection limits of 0.011 μmol/L for MP. The research not only provides a preparation method for COF with excellent nanozyme activity, but broadens some new insights for the design of highly efficient nanozymes for on-time detection for OPs.

PH-responsive dual-emission carbon dots for the ratiometric detection of organophosphorus pesticides in Brassica chinensis and Hg2+ in water

Accurate and rapid monitoring of organophosphorus pesticides (OPs) residues is crucial for regulating food safety. Herein, dual-emission carbon dots (de-CDs) were fabricated for the ratiometric detection of OPs and Hg2+. The de-CDs exhibited two emission peaks at 678 and 485 nm when excited with visible light. Interestingly, the fluorescence at 678 nm was significantly quenched by Hg2+ mainly because of the static quenching effect, whereas that at 485 nm exhibited a slight change. More significantly, the quenched fluorescence of the de-CDs recovered remarkably after introducing omethoate, diazinon and malathion. Accordingly, the ratiometric detection of the three OPs and Hg2+ was achieved with high selectivity and robust performance. In addition, the OPs residues assay in Brassica chinensis was successfully performed with satisfactory results. This study not only provides an attractive tool for the simple and rapid assay of OPs but also offers new insights into the fabrication of multi-functional carbon dots.

Surface-Enhanced Raman Spectroscopy Detection for Fenthion Pesticides Based on Gold Molecularly Imprinted Polymer Solid-State Substrates.

Current label-free surface-enhanced Raman spectroscopy (SERS) assay for the detection and analysis of organophosphorus pesticides has achieved initial success, but the application still faces constraints of substrate portability and specificity. To this end, this paper demonstrates a method for portable, rapid, and specific detection of low concentrations of fenthion pesticides based on a solid substrate of gold nanoparticle monolayers combined with molecularly imprinted polymers (MIPs). The nano-monolayers were transferred to the surface of mercapto-silicon wafers by interfacial self-assembly technique to form a stable connection with S-Au bonds and, at the same time, prevent nanoparticles from dropping off during the surfactant removal process. Then, the fenthion MIPs were directly generated on the surface of the monolayer film by spin-coating with a pre-polymerization solution and ultraviolet-induced polymerization. Tests showed that the molecular imprint was able to accurately bind to fenthion, but not other molecules, in a mixture of structural analogs, achieving a low concentration detection of 10-8 mol/L. The composite substrate maintained a signal uniformity of a relative standard deviation (RSD) = 7.05% and a batch-to-batch reproducibility of RSD = 10.40%, making it a potential pathway for the extended application of SERS technology.

Upconversion-based hydrogel kit with Python-assisted analysis platform for sample-to-result detection of organophosphorus pesticide

On-site quantitative analysis of pesticide residues is crucial for monitoring environmental quality and ensuring food safety. Herein, we have developed a reliable hydrogel portable kit using NaYbF4@NaYF4: Yb, Tm upconversion nanoparticles (UCNPs) combined with MnO2 nanoflakes. This portable kit is integrated with a smartphone reader and Python-assisted analysis platform to enable sample-to-result analysis for chlorpyrifos. The novel UCNPs maximizes energy donation to MnO2 acceptor by employing 100 % of activator Yb3+ in the nucleus for NIR excitation energy collection and confining emitter Tm3+ to the surface layer to shorten energy transfer distance. Under NIR excitation, efficient quenching of upconversion blue-violet emission by MnO2 nanoflakes occurs, and the quenched emission is recovered with acetylcholinesterase-mediated reactions. This process allows for the determination of chlorpyrifos by inhibiting enzymatic activity. The UCNPs/MnO2 were embedded to fabricate a hydrogel portable kit, the blue-violet emission images captured by smartphone were converted into corresponding gray values by Python-assisted superiority chart algorithm which achieves a real-time rapid quantitative analysis of chlorpyrifos with a detection limit of 0.17 ng mL−1. At the same time, pseudo-color images were also added by Python in “one run” to distinguish images clearly. This sensor detection with Python-assisted analysis platform provides a new perspective on pesticide monitoring and broadens the application prospects in bioanalysis.

CdTe@ZnS quantum dots for rapid detection of organophosphorus pesticide in agricultural products

Organophosphorus pesticides (OPPs) constitute the most widely employed class of pesticides. However, the prevalent use of OPPs, while advantageous, raises concerns due to their toxicity, posing serious threats to food safety. Chemical sensors utilizing quantum dots (QDs) demonstrate promising applications in rapidly detecting OPPs residues, thereby facilitating efficient inspection of agricultural products. In this study, we employ an aqueous synthesis approach to prepare low toxic CdTe@ZnS QDs with stable fluorescence properties. To mitigate the risk of imprecise measurements stemming from the inherent susceptibility of fluorescence to quenching, we have adopted the principle of fluorescence resonance energy transfer (FRET) for the construction of the turn-on quantum dot sensor. With a detection limit for chlorpyrifos as low as 10 ppb (10 μg/L), the QDs sensor exhibits notable resistance to interference from various pesticides. Application of this system to detect organophosphorothioate pesticides in apples produced results consistent with those obtained from high-performance liquid chromatography (HPLC) detection, affirming the promising application prospects of this sensing system for the rapid detection of OPPs residues.

Multifunctional 2D hemin-bridged MOF for the efficient removal and dual-mode detection of organophosphorus pesticides.

The high-residual and bioaccumulation property of organophosphorus pesticides (OPs) creates enormous risks towards the ecological environment and human health, promoting the research for smart adsorbents and detection methods. Herein, 2D hemin-bridged MOF nanozyme (2D-ZHM) was fabricated and applied tothe efficient removal and ultrasensitive dual-mode aptasensing of OPs. On the one hand, the prepared 2D-ZHM contained Zr-OH groups with high affinity for phosphate groups, endowing it with selective recognition and high adsorption capacity for OPs (285.7mgg-1 for glyphosate). On the other hand, the enhanced peroxidase-mimicking biocatalytic property of 2D-ZHM allowed rapid H2O2-directed transformation of 3,3',5,5'-tetramethylbenzidine to oxidic product, producing detectable colorimetric or photothermal signals. Using aptamers of specific recognition capacity, the rapid quantification of two typical OPs, glyphosate and omethoate, was realized with remarkable sensitivity and selectivity. The limit of detections (LODs) of glyphosate were 0.004nM and 0.02nM for colorimetric and photothermal methods, respectively, and the LODs of omethoate were 0.005nM and 0.04nM for colorimetric and photothermal methods, respectively. Theconstructed dual-mode aptasensing platform exhibited outstanding performance for monitoring OPs in water and fruit samples. This work provides a novel pathway to develop MOF-based artificial peroxidase and integrated platform for pollutant removal and multi-mode aptasensing.

Universal organophosphate pesticides detection by peptide based fluorescent probes

In practical applications, the rapid and efficient detection of universal organophosphorus pesticides (OPs) can assist inspectors in quickly identifying the presence of OPs in samples. However, this presents a challenge for most well-established methods, typically designed to detect only a specific type of organophosphorus molecule at a time. In this proof-of-concept study, we draw inspiration from the structural similarities among OPs to develop innovative peptide-based fluorescence probes for the first time, which could efficiently detect a broad range of OPs within a mere 3 min. Analysis of fluorescence curve fitting reveals a clear linear correlation between the fluorescent intensity of the peptide probes and the concentration of OPs. Additionally, the selectivity analysis indicates that these peptide fluorescent probes exhibit an excellent response to various OPs while maintaining sufficient selectivity for detecting other pesticide types. Accurate sample analysis has also highlighted the potential of these peptide probes as practical tools for the rapid detection of OPs in actual vegetable samples. In summary, this proof-of-concept study presents an innovative approach to designing and developing ultrafast, universally peptide-based OP probes. These custom-designed peptide probes may facilitate rapid sample screening and offer initial quantification for OPs, potentially saving valuable time and effort in practical OP detection.

Platinum-nickel nanoparticle-based oxidase-like nanozyme for colorimetric/photothermal dual-mode detection of organophosphorus pesticides

In this study, based on the oxidase-like (OXD) activity of platinum-nickel nanoparticles (Pt-Ni NPs) nanozyme and further in collaboration with 3,3′,5,5′-tetramethylbenzidine (TMB), a colorimetric/photothermal dual-mode probe for organophosphorus pesticides (OPs) detection was developed. TMB undergone the catalytic oxidation of Pt-Ni NPs to change from colorless to blue oxidized substance (oxTMB) and exhibited higher temperature under near-infrared irradiation. The hydrolysis product of acid phosphatase (ACP) with L-ascorbic acid 2-phosphate trisodium competed with the OXD-like activity of Pt-Ni NPs to prevent the oxidation of TMB. As the concentration of OPs grew, inhibiting the blocking effect by deactivating ACP, the generated oxTMB caused notable color and temperature changes in the reaction system. The dual-mode probe responded linearly to chlorpyrifos, with the detection limits for colorimetric and photothermal modes of 1.2 ng/mL and 1.66 ng/mL, respectively. This work proposes a simple and reliable colorimetric/photothermal platform for OPs identification, which overcomes the problem that single-mode detection probes are susceptible to external factors, and has broad application potential in the field of food safety.

Sensitive fluorescence detection of glyphosate and glufosinate ammonium pesticides by purine-hydrazone-Cu2+ complex

Organophosphorus pesticides play an important role as broad-spectrum inactivating herbicides in agriculture. Developing a method for rapid and efficient organophosphorus pesticides detection is still urgent due to the increasing concern on food safety. An organo-probe (ZDA), synthesized by purine hydrazone derivative and 2,2′-dipyridylamine derivative, was applied in sensitive recognition of Cu2+ with detection limit of 300 nM. Mechanism study via density functional theory (DFT) and job’s plot experiment revealed that ZDA and Cu2+ ions form a 1:2 complex quenching the fluorescence emission. Moreover, this fluorescent complex ZDA-Cu2+ was applicable for detecting glyphosate and glufosinate ammonium following fluorescence enhancement mechanism, with detection limits of 11.26 nM and 11.5 nM, respectively. Meanwhile, ZDA-Cu2+ was effective and sensitive when it is used for pesticide detection, reaching the maximum value and stabilizing in 1 min. Finally, the ZDA-Cu2+ probe could also be tolerated in cell assay environment, implying potential bio-application.

Oxygen-doped ZnIn2S4 as a highly active and etchable photoactive material for chlorpyrifos detection

The development of a high-performance photoactive material and an effective and efficient analysis strategy are important for photoelectrochemical (PEC) analysis. We report here the enhanced PEC activity and etchable property of oxygen-doped ZnIn2S4 (O-ZnIn2S4) and its application for PEC detection of organophosphorus pesticides (OPs). O-ZnIn2S4 prepared by thermally treating ZnIn2S4 in air atmosphere can show much higher PEC activity than pristine ZnIn2S4, because oxygen doping can decrease the band gap and thereby increase the visible-light absorption. It is found that O-ZnIn2S4 can be etched by hydrogen peroxide, so O-ZnIn2S4 can be used for PEC analysis based on the etching strategy. Enzymatic reactions catalyzed by acetylcholinesterase and choline oxidase can produce hydrogen peroxide to etch the O-ZnIn2S4 modified on photoelectrode, so a “signal-off” state is achieved. OPs can inhibit the activity of acetylcholinesterase, and the etching of O-ZnIn2S4 is weakened, enabling “signal-on” PEC detection of OPs. Chlorpyrifos is selected as a model for PEC detection of OPs. The detection limit for chlorpyrifos detection is 2 × 10−4 mg L−1 with a linear range from 0.001 to 50 mg L−1. The present study not only develops a high-performance photoactive material for PEC analysis but also provides an efficient PEC sensing strategy based on ZnIn2S4 etching.

2D magnetic nanoporous carbon with bridge-type aptamer assembly for pesticide detection based on a regenerative field-effect transistor biosensor

Field-effect transistor (FET)-based biosensors have garnered attention due to their sensitivity to surface charge changes and advantages in real-time detection. However, these biosensors often suffer from several disadvantages such as their limited sensitivity and a high cost. Here, we reported an ultra-sensitive and reusable nanoporous-based FET biosensor hybridized with bridge-type aptamers. The sensor consisted of a two-dimensional magnetic iron-cobalt nanoparticle-embedded nanoporous carbon (Fe-Co/NPC) functionalized with bridge-type aptamers. The edges of the nanopores exhibited high surface energy and chemical activity, enabling effective interactions with the aptamers. Moreover, the nanoporous structures provided additional space, which could improve molecular recognition sites and sensor sensitivity. Our sensor could be used to detect organophosphorus pesticides (OPs) in vegetables down to 100 fM in real time and identify OPs from other pesticides. Furthermore, the magnetic properties of Fe-Co/NPC allowed us to reuse a single sensor chip up to 8 times, which significantly reduced the production cost of our sensors. In this respect, our Fe-Co/NPC-FET sensor could be a powerful tool for practical applications such as food safety detection.

Detection of organophosphorus pesticides by a fluorescent sensing assay coupled with enzyme inhibition

Glyphosate (Gly), as a common organophosphorus pesticides (OPs), is being overly put into usage and it should be monitored in a timely manner. Herein, optically well-performing quantum dots (QDs) were prepared by hydrothermal synthesis to create a fluorescent sensing assay that responds to OPs and quantitatively detects Gly. The mechanism of sensing is based on OPs inhibiting enzyme activity and accompanying pH changes in the system. It can respond to multiple OPs (trichlorphon, methamidophos and chlorpyrifos). Particularly, the quantification of Gly is outstanding with a detection range of 0.2 ∼ 1.8 mg/L and the detection limit as low as 0.015 mg/L. This system has not only good selectivity and repeatability, but also reliable application potential. In spiked experiments, a recovery of 96.50∼107.00% was demonstrated. Fluorescent sensing assay coupled with enzyme inhibition provides a novel choice for pesticide detection and offers considerable value in related fields.

Developing a magnetic SERS nanosensor utilizing aminated Fe-Based MOF for ultrasensitive trace detection of organophosphorus pesticides in apple juice

The unreasonable use of organophosphorus pesticides leads to excessive pesticide residues in food, seriously threatening public health, and the potential of surface-enhanced Raman spectroscopy (SERS) technology, incorporating a metal–organic framework, is substantial for the rapid detection of trace pesticide residues. Here, a novel Fe3O4@NH2-MIL-101(Fe)@Ag (FNMA) SERS nanosensor was developed. Results indicated that the FNMA had a high enhancement factor of 1.53 × 108, a low limit of detection (LOD) of 4.55 × 10−12 M, and a relative standard deviation of 7.73 % for 4-nitrothiophenol, demonstrating its good SERS sensitivity and uniformity, and also possessed good storage stability for one month. In quantifying fenthion and methyl parathion in standard solutions and apple juice in the range of 0.05/0.02–20 mg/L, it showed LODs of 3.02 × 10−3 mg/L and 1.43 × 10−3 mg/L, and 0.0407 and 0.0075 mg/L, respectively, demonstrating potentials in ultrasensitive trace detection of pesticides in food.

Wool keratin-based colorimetric detection of organophosphorus pesticides via a multi-enzyme cascade reaction

Wool keratin-based colorimetric detection of organophosphorus pesticides via a multi-enzyme cascade reaction

Mn-modified porphyrin metal–organic framework mediated colorimetric and photothermal dual-channel probe for sensitive detection of organophosphorus pesticides

Herein, a novel dual-mode probe for organophosphorus pesticides (OPs) colorimetric and photothermal detection was developed based on manganese modified porphyrin metal–organic framework (PCN-224-Mn). PCN-224-Mn had excellent oxidase-like activity and oxidized colorless 3,3,5,5-tetramethylbenzidine (TMB) to blue–green oxidation state TMB (oxTMB), which exhibited high temperature under near-infrared irradiation. l-ascorbate-2-phosphate was hydrolyzed by acid phosphatase to produce ascorbic acid, which weakened colorimetric and photothermal signals by impacting oxTMB generation. The presence of OPs blocked the production of ascorbic acid by irreversibly inhibiting the activity of acid phosphatase, causing the restoration of chromogenic reaction and the increase of temperature. Under the optimal conditions, the probe showed a good linear response to OPs in the concentration range of 5 ∼ 10000 ng/mL, using glyphosate as the analog. The detection limits of glyphosate in colorimetric mode and photothermal mode were 1.47 ng/mL and 2.00 ng/mL, respectively. The probe was successfully used for sensitive identification of OPs residues in tea, brown rice, and wheat flour. This work proposes a simple and reliable colorimetric/photothermal platform for OPs identification, which overcomes the problem that single-mode detection probes are susceptible to external factors, and has broad application potential in the field of food safety.