Pesticide Residues In Food Research Articles

Rapid dual-modal detection of two types of pesticides in fruits using SERS-based immunoassay

Pesticide residue is a harmful chemical residue produced in agricultural production, posing a threat to human health. To detect mixed pesticide residues in food rapidly and simultaneously, we present a dual-channel dual-modal test strip immunoassay. According to the standard colorimetric bar, the naked-eye test can achieve semi-quantitative detection. By collecting the Raman spectra of the signal probes, surface-enhanced Raman scattering (SERS) detection can achieve accurate quantification of pesticide residues. Specifically, a double-layer 4-mercaptobenzoic acid (4-MBA) molecule-labeled bimetallic core-shell material (AuMBA@AgMBA) was conjugated with target antibodies to obtain signal probes. Here, antibody bonding was achieved by the dehydrated condensation of its amino group with the carboxyl group of the outer 4-MBA. In addition, the Au nanoparticles were connected to rabbit IgG by electrostatic adsorption as indicating probes to ensure the normal operation of the test strips. Under the optimal parameters, the detection ranges of acetamiprid and carbendazim were 0.3 - 2μg/kg and 3 - 30μg/kg, respectively. Furthermore, the recovery experiments showed that the results of the SERS method matched well with the high-performance liquid chromatography method. The SERS immunoassay is characterized by high sensitivity, rapidity and reliability, which has potential to simultaneously detect mixed pesticides in the field.

Self-driven photoelectrochemical sensor based on Z-type perovskite heterojunction for profenofos detection in milk and cabbage

With growing public concern about the accumulation of pesticide residues in food and their potential impacts on health and the environment, the demand for advanced detection technologies has become more critical. To address this need, we have developed an innovative self-driven photoelectrochemical (PEC) sensor, utilizing a Z-type heterojunction structure. This sensor exploited the synergistic interactions between the carbonyl groups in polyvinylpyrrolidone and the Pb2+ ions in the perovskite, and was further enhanced by the strong hydrogen bonds formed between polyethylene glycol and MA+. To optimize the sensor's performance, we incorporated perylene tetracarboxylic acid, which enhanced interface adhesion and promotes charge separation, elements crucial for the visible light-driven PEC process. This strategic design resulted in a sensor with high sensitivity and stability, which was capable of detecting profenofos residues in complex food matrices such as milk and cabbage. The sensor demonstrated a linear detection range from 0.1 to 107ngL-1 and an exceptional detection limit of 0.033ngL-1. When applied to real samples, the sensor achieved recovery rates ranging from 96.68% to 107.2%, with relative standard deviations between 1.08% and 4.54%. In light of these results, the sensor not only showed high efficiency in real-time monitoring of pesticide contamination, but also highlights its significant potential for broader application in the field of food safety.

Public Health Implications of Pesticide Residues in Food: Risks, Regulations, and Interventions

Pesticides enter food primarily through direct application to crops during farming, where residues can remain on the surface or be absorbed into plant tissues. Additionally, pesticide drift from nearby treated areas and contamination of soil or water used for irrigation can introduce residues into food crops, further increasing the risk of exposure. This paper focuses on the public health implications of pesticide residues in food. The paper found that pesticide residues in food pose significant public health challenges, with potential risks ranging from acute toxicity to chronic health issues such as cancer, endocrine disruption, and neurological disorders. Vulnerable populations, including children, pregnant women, and the elderly, are particularly at risk. Effective regulation and monitoring become crucial as the agricultural sector relies heavily on pesticides for crop protection. Regulatory bodies such as the World Health Organization (WHO), Food and Agriculture Organization of the United Nations (FAO), Environmental Protection Agency (EPA), and European Food Safety Authority (EFSA) play crucial roles in setting Maximum Residue Limits (MRLs) to ensure food safety. However, implementing these regulations faces obstacles, particularly in developing countries, where resource constraints, lack of technical expertise, and socio-economic factors impede effective monitoring. Integrating pest management (IPM), advanced monitoring techniques and consumer education are essential to mitigate the risks posed by pesticide residues. The global harmonization of pesticide standards and continued research into safer alternatives and residue detection methods are critical for ensuring a secure food supply. As agricultural practices evolve, a multi-stakeholder approach involving policymakers, farmers, and consumers will be vital in reducing pesticide exposure and safeguarding public health.

How knowledge, awareness and perceptions of pesticide residue risks in fruits and vegetables, influence purchase decisions across Malaysian communities

Understanding consumer perceptions and behaviours toward pesticide residues in food is vital for food safety and public health. This study examines the knowledge, awareness, and perceptions of 303 participants from rural, suburban, and urban Malaysian communities regarding pesticide residue risks in their food purchases, particularly fruits and vegetables. Participants completed adapted questionnaires via Google Forms or in-person interviews, covering sociodemographic information, food purchasing habits, and levels of knowledge, awareness, and perception of pesticide residues. Results indicate that urban communities have the highest knowledge about pesticide residues, followed by rural and suburban areas. Awareness levels are even across all community types, with rural areas slightly higher. Urban participants also show the highest perception levels, followed by rural and suburban communities. Rural communities demonstrate a strong positive correlation between knowledge and perception, while suburban areas show a moderately positive correlation. Urban communities exhibit significant correlations between knowledge awareness and perception, with a weaker relationship with awareness. These findings highlight the interplay between community settings and consumer behaviour in purchasing fruits and vegetables. The study emphasises the need for tailored educational and policy interventions to address the varying levels of knowledge and concerns about pesticide residues across different Malaysian communities.

Nationwide Surveillance and Cumulative Risk Assessment of Pesticide Residues in Egyptian Vegetables: Results from 2018 to 2021

Pesticide residues in food are a global concern due to their potential impacts on human health and the environment. This study investigates pesticide residues in vegetables commonly consumed in Egypt, utilizing advanced analytical techniques such as Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS) and Gas Chromatography–Tandem Mass Spectrometry (GC-MS/MS). A total of 4200 vegetable samples, including cucumber, squash, eggplant, okra, peas, onion, green onion, parsley, lettuce, and cantaloupe, were collected from 20 markets across different Egyptian governorates between 2018 and 2021. The analysis revealed that 42% of the samples contained pesticide residues, with only 13% of the analyzed samples exceeding the maximum residue limits (MRLs) established by Codex/EU-MRL standards. Despite this, the estimated daily intake (EDI) of the detected pesticides did not surpass acceptable daily intake (ADI) limits, suggesting no immediate chronic health risks to consumers. These findings highlight Egypt’s ongoing commitment to food safety, while also underscoring the importance of continuous monitoring and the promotion of sustainable agricultural practices to ensure the long-term safety and quality of the food supply.

Determination of organochlorine pesticide residues in food by polystyrene coated silica magnetic microspheres combined with gas chromatography-mass spectrometry

In this work, a sample pre-treatment technology, based on magnetite-silica-polystyrene (Fe3O4@SiO2@PS) composite as the adsorbent, combined with Gas Chromatography-Mass Spectrometry (GC–MS) has been developed and used for the trace analysis of organochlorine pesticide residues in food. SEM, TEM, FI-IR, VSM, XPS, BET, TGA and XRD techniques were used to characterize the synthetic adsorbent material, the adsorbent had excellent magnetic separation properties (saturation magnetization values with 32.7 emu g−1) and adsorption properties (adsorption capacity with 16.67 mg g−1 to 20.53 mg g−1), and the adsorption performance of Fe3O4@SiO2@PS aligned with the pseudo-second-order kinetics. Under the optimal conditions, the developed method showed satisfactory performance within a range of 0.01 to 4 mg L−1 (R2 ≥ 0.9971), the low detection limits (LOD) were from 0.05 to 0.20 μg kg−1, and the quantification limits (LOQ) were from 0.16 to 0.67 μg kg−1, respectively. The spiked recovery rates ranged from 74.7 % and 93.7 %, with relative standard deviations (RSD) from 2.09 % to 6.43 %. Thus, the developed adsorbent and method offer an efficient alternative to the commonly used SPE-based approach.

The impact of pesticides: Assessing residue persistence, environmental contamination, and human health risks

The intensification of agricultural practices to meet global food demand has led to extensive pesticide use, which poses significant challenges for food safety, environmental health, and human well-being. This narrative review provides a comprehensive analysis of the global use of pesticides in agriculture, focusing on the persistence of pesticide residues in food crops, their environmental impacts, and the associated health risks. Historically, pesticides have been integral to agricultural productivity, but their adverse effects have become increasingly clear. Notably, pesticide residues in food can pose serious health risks, particularly to vulnerable populations such as children and pregnant women. This review also discusses regional disparities in pesticide-related health outcomes, with a focus on Brazil. The findings underscore the urgent need for sustainable pest management practices, including organic farming and improved regulatory measures, to mitigate the adverse effects of pesticide use. By integrating these strategies, a more balanced and sustainable agricultural system can be achieved, safeguarding both human health and environmental quality.

Assessment of the toxic influence of locally formulated pesticides on hepatic and renal biomarkers in male Wistar rats.

There is growing concern of the potential damage to vital organs after long term exposure to locally formulated pesticides in rural area of Nigeria. This study was designed to assessed the effects of the individual chemical compound and their combination on the kidney and liver of rats' model. Fifty-four rats divided into six groups and three sub-groups were exposed to 25, 50 and 75% dose of each of the pesticide's LD50 for 4h at 3days interval in an inhalation chamber for 28days. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TOT_BIL), creatinine and urea assay showed significant increase at the aforementioned doses in comparison to the control group. The red blood cell counts, hematocrit and hemoglobin concentrations were significantly altered in the rats administered varying doses of the pesticides when compared with the control. Similar result was obtained for the differential white blood cell counts. Histopathological examinations of the liver tissue of rats showed infiltrated sinusoids, traces of karypyknosis, vacuolar degeneration and microvesicular steatosis while that of the renal tissue showed glomeruli atrophy leading to widened Bowman's spaces as well as few shrunken glomeruli and varied level of degenerative tubular changes to tubular necrosis. This study established that individual pesticides and their mixture is toxic to the liver and kidney, as evidenced by the elevated markers of renal and liver functions and distortion of the structure of both organs as revealed by their photomicrographs. Therefore, it is a matter of public health significance to regularly monitor pesticide residues in foods and humans in order to assess the food safety risk and population exposure to pesticides.

A study protocol for a randomized clinical trial on exposure and effects of pesticides consumption - the PEST-EXPO Brazil study

Randomized clinical trials are considered the gold standard for studies with dietary interventions, which is mainly due to the fact that they can establish causal relationships between food exposure and body composition measures or biomarkers. The aim of this study was to describe the details of a double-blind, randomized, clinical trial protocol to identify, characterize and evaluate the effects of human dietary exposure to pesticide residues in food. Specific aspects of planning (development of a research question, determination of objectives, selection of participants, randomization and blinding) and performance (recruitment of participants, measures to improve adherence, data collection, follow-up and evaluation of results) are addressed in this study. The study design proved effective in characterizing dietary patterns with foods originating from both conventional and organic agriculture. A total of 148 individuals were recruited for the study. The conventional group was represented by 47 % of the sample and the organic group was represented by 53 %. The practice of evidence-based nutrition has demanded that trials be well designed and systematically performed in the field of clinical nutrition. Therefore, this clinical trial emphasizes the importance of improving studies with toxicological nutrition that assess sources of exposure through food.•This double-blind, randomized clinical trial details the protocol for identifying, characterizing, and evaluating the effects of dietary exposure to pesticide residues.•The protocol demonstrates that well-designed and systematically conducted trials emphasize the importance of robust methodologies in evidence-based nutrition.•In the face of the global climate crisis, this clinical trial underscores the importance of enhancing studies in toxicological nutrition, particularly those evaluating sources of exposure through food, to better understand the dietary impacts on health.

Dual colorimetric platforms for direct detection of glyphosate based on Os-Rh nanozyme with peroxidase-like activity

BackgroundTo minimize the impact of pesticide residues in food on human health, it is necessary to enhance their detection. Recently, many nanozyme-based colorimetric methods for pesticides detection have been developed, however, they often required the assistance of natural enzymes, which made the process and result of methods susceptible to the stability and activity of natural enzymes. To overcome these drawbacks, methods for direct detection of pesticides using nanozymes have been developed, and there are few studies in this field currently. Thus, it is of great research and practical significance to develop more nanozymes-based colorimetric methods for direct detection of pesticides. ResultsDual colorimetric platforms based on Os-Rh nanozyme with excellent peroxidase-like activity were constructed for directly detection of glyphosate in this work. Results showed that glyphosate was able to sensitively and selectively inhibit the peroxidase-like activity of Os-Rh nanozyme through hindering the decomposition of H2O2 by Os-Rh nanozyme to produce HO∙. Based on this, the dual colorimetric platforms achieved highly sensitive detection for glyphosate over a wide linear concentration range (50–1000 μg L−1 in solution platform and 200–1000 μg L−1 in paper platform), with the detection limits of 28.37 μg L−1 in solution platform and 400 μg L−1 (naked-eye detection limit)/123.25 μg L−1 (gray scale detection limit) in paper platform, respectively. Moreover, the dual colorimetric platforms possessed satisfactory reliability and accuracy for practical applications, and has been successfully applied to the detection of real samples with the spiked recoveries of 92.78–102.75 % and RSD of 1.17–3.88 %. SignificanceThe dual colorimetric platforms for glyphosate direct detection based on Os-Rh nanozyme developed in this work not only owned considerable practical application potential, but also could provide more inspirations and ideas for the rational design and development of colorimetric sensing methods for the rapid detection of pesticides based on nanozymes.

Hierarchical magneto-colorimetric labels for immediate lateral flow immunoassay of chlorothalonil residues

Quantitative detection of pesticide residues in food and environmental samples using an improved lateral flow immunoassay (LFIA) is of considerable importance for real-time analysis. This paper proposes a highly sensitive LFIA platform based on a hierarchical magneto-colorimetric compact. This compact serves as both the target magnetic enrichment substrate and a photosensitive label. Initially, a large porous dendritic silica template is prepared and doped with superparamagnetic ferric oxide nanoparticles (Fe3O4 NPs) and colloidal gold nanoparticles (AuNPs) at high densities within its vertical channels. The sequential assembly of central–radial channels allow for the three-dimensional integration of these two components, enabling independent control of their discrete functions without mutual interference. Following alkyl organosilicon encapsulation and silica sealing, the composite spheres are then applied in LFIA to detect chlorothalonil residues. Fe3O4 NPs enhance the binding efficiency to target analytes, while AuNPs amplify the signal, leveraging their high loading densities and robust optical properties. The developed LFIA platform exhibited a detection limit of 0.34 ng/mL for chlorothalonil and a linear range of 0.0085–824 ng/mL. The recoveries varied between 85.1 % and 103.1 %, and the relative standard deviations were 1.25%–8.84 %. This LFIA approach demonstrates high sensitivity, specificity, reproducibility and flexible detection modes, making it highly suitable for the on-site monitoring of pesticide residues.

Assessing external exposome by implementing an Environmental Data Management System using Open Data

Due to the increasing importance of exposome in environmental epidemiology, feasibility and usefulness of an Environmental Data Management System (EDMS) using Open Data was evaluated. The EDMS includes data from 10 European cities (Celje (Slovenia), Łódź (Poland), Manchester (UK), Palermo (Italy), Paris (France), Porto (Portugal), Regensburg (Germany), Reus (Spain), Rijeka (Croatia), Thessaloniki (Greece)) about external non-specific and specific exposome factors at the city or country level (2017–2020). Findings showed that the highest values of life expectancy were in Reus females (86 years) and Palermo males (81 years). UK had the highest obesity rate (28%), Croatia the highest prescribed drug consumption (62%), Greece and Portugal the highest smoking rates (37%, 42%) and daily alcohol consumption (21%), respectively. The most polluted cities were Thessaloniki for PM10 (38 µg/m3), Łódź for PM2.5 (25 µg/m3), Porto for NO2 (62 µg/m3) and Rijeka for O3 (92 µg/m3). Thessaloniki had the highest grey space (98%) and Łódź the highest cumulative amount of pollen (39,041 p/m3). The highest daily noise levels ≥ 55 dB was in Reus (81% to traffic) and Regensburg (21% to railway). In drinking water, arsenic had the highest value in Thessaloniki (6.4 µg/L), boron in Celje (24 mg/L) and lead in Paris (46.7 µg/L). Portugal and Greece showed the highest pesticide residues in food (7%). In conclusion, utilizing open-access databases enables the translation of research findings into actionable strategies for public health interventions.

Comparison of nitrogen and helium as carrier gases for determination of pesticide residues in foods via gas chromatography–tandem mass spectrometry with atmospheric pressure chemical ionization

The applicability of nitrogen as an alternative carrier gas to helium for the multiresidue analysis of pesticides using gas chromatography–tandem mass spectrometry with atmospheric pressure chemical ionization (GC–(APCI)MS/MS) was examined. The methods using both carrier gases were validated for 151 pesticides in foods at a spiking level of 0.01 ppm, maintaining identical conditions for both gases, including the GC column and carrier gas flow rate. The use of nitrogen resulted in slightly broader peaks and lower peak intensities that those observed upon using helium. However, sufficient sensitivity was achieved for all target compounds because of the high sensitivity of the GC–(APCI)MS/MS method. Further, target-compound separation was not significantly affected by the carrier gas type, and no interfering peaks were observed, demonstrating the high selectivity of the nitrogen-based method, even beyond the optimum linear velocity. Finally, the analytical performance of the nitrogen-based method was comparable to those of the helium-based method. Considering cost-effectiveness of nitrogen, this method is highly valuable in the event of helium shortages and for routine pesticide residue monitoring.

Pesticide residues in food of plant origin commercialized in Brazil from 2010 to 2020 – An update from the two national monitoring programs

The objective of this study was to investigate the results of the two Brazilian national pesticide residue monitoring programs obtained from January 2010 to December 2020. A total of 35,321samples of 44 different food crops were analyzed, of which 55.3% tested positive for at least one compound, with pear, peach, strawberry and sweet pepper having over 90% of the analyzed samples containing residues. Approximately one-third of the positive samples had at least one irregularity, of which 86.7% due to the presence of non-authorized pesticides for the crop, 26.3% exceeding the maximum residue level, and 13.1% showing both irregularities. A total of 191 different compounds were detected, primarily organophosphorus (OP) (37.4% of positive samples, of which over 60% of cereal/flour, potatoes, and peanuts). Chlorpyrifos, acephate, pirimiphos-methyl, and methamidophos were the main OPs detected. Triazoles were present in 27.2% of the positive samples, mainly rice, and pyrethroids in 22.4% of the positive samples, mainly in popcorn. Dithiocarbamates were present in 19.7% of the positive samples, predominantly in apples, and 5.0% of the positive samples contained N-methyl carbamates, mainly in sweet peppers. Carbendazim was the most detected pesticide (30% of positive samples), mainly in papaya (18.2% of samples containing this pesticide). About 60% of positive samples contained multiple residues, primarily in sweet pepper, pear, strawberry, and orange (over 80% of positive samples). Compared to the previous decade (2001–2010), these results indicated increased percentages of positive, irregular and of samples containing multiple residues. Dithiocarbamates were no longer the most detected pesticide group, while carbendazim remained the most detected pesticide in both periods.

Analysis of Chlorpyrifos Pesticide Residue in Locally Grown Cauliflower, Cabbage, and Eggplant Using Gas Chromatography-Mass Spectrometry (GC-MS) Technique: A Bangladesh Perspective.

Pesticides are chemical substances used to kill or control various types of pests, which are hazardous for crops and animals. Pesticides may remain on or in foods after these are applied to crops. Pesticide residue in food has been a major global concern since there are direct and indirect health hazards associated with the regular consumption of foods with pesticide residues. Chlorpyrifos is one of the most used pesticides that has received much attention worldwide due to its detrimental health impact. The presence of chlorpyrifos residue in food crops can have both long-term and short-term effects on consumer health. Bangladesh is an agricultural country that uses a high volume of pesticides every year including chlorpyrifos. This experimental study aimed to analyze chlorpyrifos pesticide residue in locally grown cauliflower, cabbage, and eggplant samples by gas chromatography-mass spectrometry (GC-MS) technique followed by a suitable extraction process. Commercially available cauliflower, cabbage, and eggplant samples along with samples cultivated with the recommended pesticide dose were collected for qualitative and quantitative analysis. Samples cultivated without chlorpyrifos were collected as control samples for the validation study. The method was validated with respect to accuracy, recovery, reproducibility, linearity, limit of detection, and limit of quantification. The method has a limit of detection (LOD) of 0.011 mg/kg and a limit of quantification (LOQ) of 0.034 mg/kg. The experimental results were compared to the maximum residue level (MRL) to assess the human health impact. Chlorpyrifos residue was found in 44% of cauliflower samples with 91% of samples higher than MRL. The residue was found in 68% of cabbage samples with 53% of samples higher than MRL. For eggplant, the residue was found in 80% of the samples with 65% of samples higher than MRL. The risk assessment based on the residue level found in this study shows a potential health hazard of having a high concentration of chlorpyrifos residue in locally grown vegetables.

Mechanistic understanding of nanoparticle interactions to achieve highly-ordered arrays through self-assembly for sensitive surface-enhanced Raman scattering detection of trace thiram

Over the last few decades, there is increasing worldwide concern over human health risks associated with extensive use of pesticides in agriculture. Developing excellent SERS substrate materials to achieve highly sensitive detection of pesticide residues in the food is very necessary owing to their serious threat to human health through food chains. Self-assembled metallic nanoparticles have been demonstrated to be excellent SERS substrate materials. Hence, alkanethiols-protected gold nanoparticles have been successfully prepared for forming larger-scale two-dimensional monolayer films. These films can be disassembled into a fluid state and re-assembled back to crystallized structure by controlling surface pressure. Further investigations reveal that their self-assembled structures are mainly dependent on the diameter of gold nanoparticles and ligand length. These results suggest that the size ratio of nanoparticle diameter/ligand length within the range of 4.45–2.35 facilitates the formation of highly ordered 2D arrays. Furthermore, these arrays present excellent Surface-Enhanced Raman Scattering performances in the detection of trace thiram, which can cause environmental toxicity to the soil, water, animals and result in severe damage to human health. Therefore, the current study provides an effective way for preparing monodispersed hydrophobic gold nanoparticles and forming highly ordered 2D close-packed SERS substrate materials via self-assembly to detect pesticide residues in food. We believe that, our research provides not only advanced SERS substrate materials for excellent detection performance of thiram in food, but also novel fundamental understandings of self-assembly, manipulation of nanoparticle interactions, and controllable synthesis.

Synergistic Enhancement Effect of Ag/rGO as SERS Platform for Capture and Trace Detection of Fenvalerate Molecules

Surface-enhanced Raman scattering (SERS) provides an alternative rapid detection method for pesticide residues in food, but fenvalerate possesses poor affinity to the novel metal substrate, thus restricting its analysis. To break this bottleneck, a SERS-active platform with an Ag/rGO composite structure was engineered using a facile method for fenvalerate detection. Ag nanoparticles with a 60 nm diameter can grow evenly on the top and bottom of rGO layers under intense ultrasonic oscillation, and rGO in hybrid material acts as an ideal hotspot holder between the gaps of Ag nanoparticles, not only allowing the interaction area to be enhanced both electromagnetically and chemically but also enabling the capture and enrichment of fenvalerate pesticide molecules into the “hotspot” area to improve detection sensitivity. Ag/rGO composite substrate possesses superior SERS performance with an ultralow detectable concentration of 4-aminothiophenol (10−10 M) and good reproducibility, endowing the material with a better enhancement effect than pure Ag nanoparticles. When used as the SERS substrate for fenvalerate detection, Ag/rGO composite material showed excellent performance in both experiments and theoretical calculation, with the limit of detection (LOD) of fenvalerate being as low as 1.69 × 10−5 mg/kg and a detection model with an R2 of 99.2%, demonstrating its exciting potential as a SERS substrate for pesticides detection.

Gold nanoparticle-mediated molecularly imprinted electrochemical sensor MIP/AuNPs/GCE for highly sensitive and selective detection of neutral phosmet residues in fruits and vegetables

A novel electrochemical sensor MIP/AuNPs/GCE was developed by depositing gold nanoparticles and electropolymerizing molecularly imprinted film on the surface of glassy carbon electrode (GCE) for highly sensitive detection of neutral phosmet residues in fruits and vegetables. Scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy, cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the imprinted sensor. The results showed that the imprinted film on GCE was evenly prepared with better specific recognition of phosmet on MIP/AuNPs/GCE than that on bare GCE. Several parameters including deposition time, functional monomer and its molar ratio, scanning cycles, and elution time were optimized in detail. The linear range of the MIP/AuNPs/GCE prepared in this work was 0.020–4.0 nmol/L with limit of detection of 0.010 nmol/L, which was much lower than MIP/GCE (0.17 nmol/L). The identification mechanism of MIP/AuNPs/GCE for phosmet was also confirmed as adsorption-diffusion model with effective surface area increasing after mediated by AuNPs. Selectivity, reproducibility and repeatability of the MIP/AuNPs/GCE were acceptable. The recovery of applying the sensor to detect PM in real samples ranged from 91.40 % to 107.3 %, which agreed well with those of HPLC. The method of developing MIP/AuNPs/GCE sensor herein could be extended to detecting other neutral pesticide residues in food and environment.

MOF-derived multi-"hotspot" 3D Au/MOF-808 (Zr) nanostructures as SERS substrates for the ultrasensitive determination of thiram.

Aconvenient self-assembly methodis proposed for synthesis of 3D Au/MOF-808 (Zr) composite nanostructures with a cerium metal-organic framework loaded with gold nanoparticles. We combine adsorption properties of MOF materials with surface plasmon resonance of noble metals to construct hotspot-dense 3D Au/MOF-808 (Zr) SERS substrates, by using a two-step method of solvothermal and reduction reactions. The results show that optimal SERS substrates are obtained from a volume ratio of gold nanoparticles to MOF-808 (Zr) solution of 4:1 and a self-assembly time of 2h. Rhodamine 6G (R6G) is used as a molecular probe to characterize and analyze SERS properties of substrates of 3D Au/MOF-808 (Zr) prepared under the optimal process conditions, where the substrates are capable to detect R6G concentrations down to 10-10 M with a relative standard deviation of 8.81%. Finally, we applied the SERS substrates of 3D Au/MOF-808 (Zr) to the detection of pesticide thiram, and establish a quantitative determination method. 3D Au/MOF-808 (Zr) provides a sensitive detection of thiram in lake water by SERS with a detection limit of 1.49 × 10-9 M. Application tests show that a SERS enhancement factor of the MOF-based SERS substrates for the detection of thiram can be significantly increased to 5.91 × 105. Thus, the above results indicate that such substrate has high sensitivity, good adsorption, homogeneity, and reproducibility, which can be extended for sensitive detection of pesticide residues in food and environment.

Potential powered EC-SERS for sensitive detection of acetamiprid

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for rapid and sensitive detection of pesticide residues in food, and the applied potential regulated SERS technique can be endowed with a higher sensitivity. In this work, we developed an electrochemical-surface enhanced Raman spectroscopy (EC-SERS) sensor for the rapid detection of acetamiprid (AAP) in vegetables. AuNPs/ITO were prepared via in-situ electrodeposition of gold nanoparticles (AuNPs) on an indium tin oxide (ITO) both as a SERS substrate and working electrode. By adding AAP into an in-situ Raman electrolytic cell with an applied electrochemical potential (+0.3 V), the SERS intensity was enhanced by 4-fold and the characteristic signal was linearly related to the concentration of AAP. Under the optimal conditions, the EC-SERS method exhibited a linear detection range from 0.05 to 50 μM, with a limit of detection (LOD, 3S/M) of 0.02 μM. Simultaneously, based on density functional theory (DFT), the adsorption characteristics of AAP on AuNPs/ITO were studied in the presence of electric field. The method was finally confirmed by HPLC-MS for the detection of real samples, revealing its potential application in food safety.