Pesticide Residues in Organic and Conventional Agricultural Soils across Europe: Measured and Predicted Concentrations.

During the growing season of 2021, 201 soil samples from conventionally and organically managed fields from 10 European countries and 8 cropping systems were taken, and 192 residues of synthetic pesticides were analyzed. Pesticide residues were found in 97% of the samples, and 88% of the samples contained mixtures of at least 2 substances. A maximum of 21 substances were found in conventionally managed fields, and a maximum of 12 were found in organically managed fields. The number and concentration of pesticide residues varied significantly between conventional and organic fields in 70 and 50% of the case study sites, respectively. Application records were available for a selected number of fields (n = 82), and these records were compared to the detected substances. Residues from 52% of the applied pesticides were detected in the soils. Only 21% of the pesticide residues detected in the soil samples were applied during the 2021 growing season. From the application data, predicted environmental concentrations of residues in soil were calculated and compared to the measured concentrations. These estimates turned out not to be accurate. The results of this study show that most European agricultural soils contain mixtures of pesticide residues and that current calculation methods may not reliably estimate their presence.

Rice quality prediction and assessment of pesticide residue changes during storage based on Quatformer.

Rice serves as a fundamental food staple for humans. Its production process, however, unavoidably exposes it to pesticides which may detrimentally impact its quality due to residues. Therefore, it is extremely necessary to monitor pesticide residues on rice during storage. In this research, the Quatformer model, which considers the effects of temperature and humidity on pesticide residues in rice grains, was utilized to forecast the amount of pesticide residues in rice grains during the storage process, and the predicted results were combined with actual observations to form a quality assessment index. By applying the K-Means algorithm, the quality of rice grains was graded and assessed. The findings indicated that the model had high prediction accuracy, and the MAE, MSE, MAPE, RMSE and SMAPE indexes were calculated to be 0.0112, 0.0814, 0.1057, 0.1055 and 0.0204, respectively. These findings provide valuable technical and theoretical support for planning storage conditions, enhancing pesticide residue decomposition, and monitoring rice quality during storage.

[Effects of Pesticides Use on Pesticides Residues and Its Environmental Risk Assessment in Xingkai Lake（China）].

Xingkai Lake, located in Heilongjiang Province, is an important fishery and agricultural base and is seriously polluted by agricultural non-point sources. To clarify the residual status of many pesticides in the surface water of Xingkai Lake, 27 types of pesticides, herbicides, and their degradation products were analyzed in rice paddy, drainage, and surface water around Xingkai Lake (China) during the rice heading and maturity periods. The results showed that all 27 types of pesticides, herbicides, and their degradation products were detected during the rice heading period, and the total concentration ranged from 247.97 to 6 094.49 ng·L-1. Additionally, 25 species were detected during the rice maturity period, and the total concentration ranged from 485.36 to 796.23 ng·L-1. In comparison, more pesticides, herbicides, and derived degradation products were detected during the heading period, and their total concentration was higher as well. During the rice heading period, atrazine, simetryn, and paclobutrazol were the main detected pesticides, atrazine and isoprothiolane were the main pesticides detected during the maturity period. The distribution characteristics of pesticides and herbicides in the surface water around Xingkai Lake (China) was similar to that in drainage, so they were probably imported from the drainage and rice paddy. The average risk quotient (RQ) values of atrazine, simetryn, prometryn, butachlor, isoprothiolane, and oxadiazon were higher than 0.1 in drainage and Xingkai Lake (China), which showed a potential risk to aquatic organisms.

Residue levels, processing factors and risk assessment of pesticides in ginger from market to table.

Ginger is consumed as a spice and medicine globally. However, pesticide residues in ginger and their residue changes during processing remain poorly understood. Our results demonstrate that clothianidin, carbendazim and imidacloprid were the top detected pesticides in 152 ginger samples with detection rates of 17.11-27.63%, and these pesticides had higher average residues of 44.07-97.63 µg/kg. Although most samples contained low levels of pesticides, 66.45% of the samples were detected with pesticides, and 38.82% were contaminated with 2-5 pesticides. Peeling, washing, boiling and pickling removed different amounts of pesticides from ginger (processing factor range: 0.06-1.56, most <1). By contrast, pesticide residues were concentrated by stir-frying and drying (0.50-6.45, most >1). Pesticide residues were influenced by pesticide physico-chemical parameters involving molecular weight, melting point, degradation point and octanol-water partition coefficient by different ginger processing methods. Chronic and acute dietary risk assessments suggest that dietary exposure to pesticides from ginger consumption was within acceptable levels for the general population. This study sheds light on pesticide residues in ginger from market to processing and is of theoretical and practical value for ensuring ginger quality and safety.

Integrating transformer-based machine learning with SERS technology for the analysis of hazardous pesticides in spinach.

This study introduces an innovative strategy for the rapid and accurate identification of pesticide residues in agricultural products by combining surface-enhanced Raman spectroscopy (SERS) with a state-of-the-art transformer model, termed SERSFormer. Gold-silver core-shell nanoparticles were synthesized and served as high-performance SERS substrates, which possess well-defined structures, uniform dispersion, and a core-shell composition with an average diameter of 21.44 ± 4.02 nm, as characterized by TEM-EDS. SERSFormer employs sophisticated, task-specific data processing techniques and CNN embedders, powered by an architecture features weight-shared multi-head self-attention transformer encoder layers. The SERSFormer model demonstrated exceptional proficiency in qualitative analysis, successfully classifying six categories, including five pesticides (coumaphos, oxamyl, carbophenothion, thiabendazole, and phosmet) and a control group of spinach data, with 98.4% accuracy. For quantitative analysis, the model accurately predicted pesticide concentrations with a mean absolute error of 0.966, a mean squared error of 1.826, and an R2 score of 0.849. This novel approach, which combines SERS with machine learning and is supported by robust transformer models, showcases the potential for real-time pesticide detection to improve food safety in the agricultural and food industries.

[Determination of 222 pesticide residues in olive oil by fully automatic QuEChERS pre-treatment instrument coupled with gas chromatography-quadrupole-time-of-flight mass spectrometry].

Pesticide residues may be present in olive oil because pesticides are applied to olive trees during their cultivation and growth for pest prevention and some of these pesticides are not easily degraded. Studies on pesticide residues in olive oil have mainly focused on the detection of single types of pesticide residues, and reports on the simultaneous detection of multiple pesticide residues are limited. At present, hundreds of pesticides with different polarities and chemical properties are used in practice. In this study, an analytical method based on fully automatic QuEChERS pretreatment instrument coupled with gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOF-MS) was established for the rapid determination of 222 pesticide residues in olive oil. The effects of acetonitrile acidification concentration, n-hexane volume, oscillation time, centrifugation temperature, and purification agent on the determination of the 222 pesticide residues were investigated. First, ions with good responses and no obvious interference were selected for quantification and characterization. The purification process was then developed by setting the parameters of the fully automatic QuEChERS pretreatment instrument to optimal values. The sample was extracted with acetonitrile containing 2% formic acid, and the supernatant was purified by centrifugation in a centrifuge tube containing 400 mg N-propylethylenediamine (PSA), 400 mg octadecylsilane-bonded silica gel (C18), and 1200 mg anhydrous magnesium sulfate. The purified solution was blown dry with nitrogen and then fixed with ethyl acetate for instrumental analysis. Finally, a matrix standard solution was used for quantification. The method was validated in terms of matrix effects, linear ranges, limits of detection (LODs) and quantification (LOQs), accuracies, and precisions. The results showed that 86.04% of the 222 pesticides had linear ranges of 0.02-2.00 µg/mL, 10.81% had linear ranges of 0.10-2.00 µg/mL, and 3.15% had linear ranges of 0.20-2.00 µg/mL. The pesticide residues showed good relationships within their respective linear ranges, and the correlation coefficients (R2) were greater than 0.99. The LODs of all tested pesticides ranged from 0.002 to 0.050 mg/kg, and their LOQs ranged from 0.007 to 0.167 mg/kg. Among the 222 pesticides determined, 170 pesticides had LOQs of 0.007 mg/kg while 21 pesticides had LOQs of 0.017 mg/kg. At the three spiked levels of 0.2, 0.5, and 0.8 mg/kg, 79.58% of all tested pesticides had average recoveries of 70%-120% while 65.92% had average recoveries of 80%-110%. In addition, 93.54% of all tested pesticides had relative standard deviations (RSDs, n=6)<10% while 98.35% had RSDs (n=6)<20%. The method was applied to 14 commercially available olive oil samples, and seven pesticides were detected in the range of 0.0044-0.0490 mg/kg. The residues of fenbuconazole, chlorpyrifos, and methoprene did not exceed the maximum limits stated in GB 2763-2021. The maximum residual limits of molinate, monolinuron, benalaxyl, and thiobencarb have not been established. The method utilizes the high mass resolution capability of TOF-MS, which can improve the detection throughput while ensuring good sensitivity. In addition, high-resolution and accurate mass measurements render the screening results more reliable, which is necessary for the high-throughput detection of pesticide residues. The use of a fully automatic QuEChERS instrument in the pretreatment step reduces personnel errors and labor costs, especially when a large number of samples must be processed, thereby offering significant advantages over other approaches. Moreover, the method is simple, rapid, sensitive, highly automatable, accurate, and precise. Thus, it meets requirements for the high-throughput detection of pesticide residues in olive oil and provides a reference for the development of detection methods for pesticide residues in other types of oils as well as the automatic pretreatment of complex matrices.

Investigation of dissipation kinetics and half-lives of fipronil and thiamethoxam in soil under various conditions using experimental modeling design by Minitab software.

To determine the extent of pesticide buildup and their environmental contamination, the environmental half-lives of pesticides are examined. The influence of the factors affecting the half-lives of fipronil and thiamethoxam including soil type, sterilization, temperature, and time and their interactions was studied using experimental modeling design by Minitab software. Based on the dissipation kinetics data, fipronil concentrations reduced gradually over 60 days while thiamethoxam concentrations decreased strongly. Also, fipronil and thiamethoxam dissipated more rapidly in calcareous soil than in alluvial soil. Thiamethoxam, however, disappeared more rapidly than fipronil in all treatments. Incubation at 50 °C leads to rapid the pesticide degradation. For prediction of the dissipation rate, model 5 was found to be the best fit, Residue of insecticide (%) = 15.466 - 11.793 Pesticide - 1.579 Soil type + 0.566 Sterilization - 3.120 Temperature, R2 = 0.94 and s = 3.80. Also, the predicted DT50 values were calculated by a model, DT50 (day) = 20.20 - 0.30 Pesticide - 7.97 Soil Type + 0.07 Sterilization - 2.04 Temperature. The shortest experimental and predicted DT50 values were obtained from treatment of thiamethoxam at 50 °C in calcareous soil either sterilized (7.36 and 9.96 days) or non-sterilized (5.92 and 9.82 days), respectively. The experimental DT50 values of fipronil and thiamethoxam ranged from 5.92 to 59.95 days while, the modeled values ranged from 9.82 to 30.58 days. According to the contour plot and response surface plot, temperature and sterilization were the main factors affecting the half-lives of fipronil and thiamethoxam. The DT50 values of fipronil and thiamethoxam increased in alluvial soil and soil with low temperature. In general, there is a high agreement between the experimental results and the modeled results.

Residual estimation of spirotetramat and its metabolites in chilli and soil by LC-MS/MS.

Two applications of spirotetramat were done to study the dissipation and persistence of spirotetramat and its four different metabolites in chilli and soil at 10 days interval. Total spirotetramat residues were estimated by LC-MS/MS instrument. The mean initial deposits of total spirotetramat after application of spirotetramat 15.31 OD @ 60 (X dose), 75 (1.25 × dose) and 120 (2 × dose) g a.i. ha-1 on green chilli were found to vary from 0.38 to 0.83 mg kg-1 during the initial year. Spirotetramat and its metabolite residues in green chilli were found to be below limit of quantification (0.01 mg kg-1) after 15 days of application. The spirotetramat cis enol (the major metabolite) was formed in both the soil and the plant. The residues of spirotetramat-monohydroxy were below LOQ irrespective of any substrate during the estimation. In soil, the total initial spirotetramat deposits for the 1st year were found 0.09 for X dose, 0.12 for 1.25 × dose and 0.20 mg kg-1 for 2 × dose. After 3 days for both X and 1.25 × doses and 5 days for 2 × dose, the total spirotetramat residues were below LOQ. The spirotetramat's half-life values have been determined to be between 3.19 and 3.93 days and 1.00 and 1.59 days, respectively, in soil and green chilli fruits. One day waiting period is proposed for the safe consumption of green chilli when the spirotetramat was applied irrespective of the dose.

Pesticide residues in fresh Mazafati date fruit, soil, and water, and assessment of potential health risks to consumers.

A quantitative method based on quick, easy, cheap, effective, rugged, and safe technique (QuEChERS) sample extraction and ultra-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS) was evolved for the determination of 47 pesticide residues in fresh Mazafati date fruits from Bam City of Kerman Province, Iran. The recoveries for selected pesticides ranged from 88 to 110% with a relative standard deviation (RSD) of less than 20% at concentrations of 0.05 and 0.1 mg kg-1. The proposed method had a linear range from the limit of quantification (LOQ) to 1.00 mg kg-1, and the LOQ of the 47 pesticides was ≤ 0.005 mg kg-1. The coefficients of determination (R2) were more than 0.99. This technique was used on 12 fresh date fruits samples, three water samples, and three soil samples with three replications per sample. Forty-seven pesticide were detected collectively, but only diazinon was detected in the date fruit samples. The mean value of diazinon residues was 0.037 mg kg-1, and the concentration of diazinon in most samples was below the national maximum residue limit (MRL) for date fruit (0.05 mg kg-1). Among the pesticides measured, diazinon residues were also detected in the water samples, but not in the soil samples. The dietary intake assessment showed no health risk to humans from the consumption of fresh date fruit concerning the pesticides investigated.

Residue behavior and consumer risk assessment of spirotetramat and chlorpyrifos on cabbage heads and cropped soil.

A field experiment following good agricultural practices was laid out to study the dissipation of spirotetramat (90 g a.i. ha-1 and 180 g a.i. ha-1) and chlorpyrifos (400 g a.i. ha-1 and 800 g a.i. ha-1) on cabbage heads and soil. Samples were processed using quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for residue estimation of spirotetramat and chlorpyrifos, which were further detected using HPLC-PDA and GC-FPD respectively. The residues of spirotetramat on cabbage heads reached below detection limit (BDL) (< 0.05 mg kg-1) on 7th and 10th day and for chlorpyrifos, BDL (< 0.01 mg kg-1) was achieved on 10th and 15th day for X and 2X dose, respectively. On 20th day after second spray, residues in soil were found to be BDL for both the pesticides. Half-life of spirotetramat and chlorpyrifos was found to be 3 and 2 days, respectively while a safe pre-harvest interval (PHI) of 9 days for spirotetramat and 10 days for chlorpyrifos is suggested on cabbage. The dietary risk assessment studies for various age groups of Indian population, ascertained safety of treated cabbage heads for consumption, as current study revealed that hazard quotient (HQ) < 1 and theoretical maximum dietary intake (TMDI) < maximum permissible intake (MPI) for both the pesticides at respective PHI.

Occurrence and health risk of pesticide residues in Chinese herbal medicines from Shandong Province, China.

Pesticide residue was one of the stress factors affecting quality and safety of Chinese herbal medicines (CHMs). The present study was designed to investigate the occurrence and dietary exposure of 70 pesticide residues in 307 samples of CHMs, including 104 American ginseng, 100 Ganoderma lucidum (G. lucidum), and 103 Dendrobium officinale (D. officinale) in Shandong Province, China. The study revealed that a total of 29 pesticides were detected in the majority (92.5%) of samples, and the pesticide residues of 85 (27.7%) samples exceeded the maximum residue levels (MRLs). Particularly, the maximum concentration of chlorpyrifos was 23.8 mg kg-1, almost 50 times of the MRLs in food in GB 2763-2021, while there's no standard restrictions specified in CHMs in China. The chronic, acute, and cumulative risk assessment results indicated that risk exposure of the three types of CHMs were unlikely to pose a health risk to consumers. However, more attention should be paid to the multiple residues with the presence of four or more pesticides in one sample and high over-standard rate of pesticides. The pesticide users and the government should pay more attention to the pesticides used in CHMs and regularly monitor the presence of these compounds. The study recommended the MRLs of these pesticides in CHMs should be established and perfected by the relevant departments in China.

Development of a processing factor prediction model for pesticides in processed tomato foods using elastic net regularization.

A novel regularized elastic net regression model was developed to predict processing factor (PF) for pesticide residues, which represents a change in the residue levels during food processing. The PF values for tomato juice, wet pomace and dry pomace in the evaluations and reports published by the Joint FAO/WHO Meeting on Pesticide Residues significantly correlated with the physicochemical properties of pesticides, and subsequently the correlation was observed in the present tomato processing study. The elastic net regression model predicted the PF values using the physicochemical properties as predictor variables for both training and test data within a 2-fold range for 80-100% of the pesticides tested in the tomato processing study while overcoming multicollinearity. These results suggest that the PF values are predictable at a certain degree of accuracy from the unique sets of physicochemical properties of pesticides using the developed model based on a processing study with representative pesticides.

Effect of vine leaves processing on Azoxystrobin, Fenazaquin and Indoxacarb residues dissipation: processing factors and consumer safety assessment.

The effect of vine leaves processing techniques on Azoxystrobin, Fenazaquin, and Indoxacarb residues was investigated. Residue extraction following field application of pesticides and leaf processing was carried out using the QuEChERS method, with analysis conducted by LC-MS/MS. In dry conservation, Azoxystrobin's half-life was estimated to exceed a year, Fenazaquin's was 18 days, and Indoxacarb's was 142 days. Azoxystrobin had a half-life of 261 days, Fenazaquin had a half-life of 9 days, and Indoxacarb's half-life exceeded a year in brine conservation. It is recommended to use dry conservation because it results in an average 60 % reduction in residue levels for the three pesticides. Boiling water significantly reduced pesticide residues (Azoxystrobin -40.3 %, Indoxacarb -22.4 %, and Fenazaquin -28.8 %). It is recommended to use boiling water for washing, as it shows an average removal rate of approximately 30 %. The health risk assessment indicated that consuming vine leaves posed no health risk for consumers, but overall exposure to residues must be considered.

Diffusion of organochlorine (OCPs) and cypermethrin pesticides from rohu (Labeo rohita) internal organs to edible tissues during ice storage: a threat to human health.

The migration of organochlorine pesticides (OCPs) and cypermethrin residues from internal organs to edible tissues of ice-held Labeo rohita (rohu) was investigated in this study. The liver (246 µg/kg) had the highest level of ∑OCP residues, followed by the gills (226 µg/kg), intestine (167 µg/kg), and muscle tissue (54 µg/kg). The predominant OCPs in the liver and gut were endosulfan (53-66 µg/kg), endrin (45-53 µg/kg), and dichloro-diphenyl-trichloroethane (DDT; 26-35 µg/kg). The ∑OCP residues in muscle increased to 152 µg/kg when the entire rohu was stored in ice, but they decreased to 129 µg/kg in gill tissues. On days 5 and 9, the total OCPs in the liver increased to 317 µg/kg and 933 µg/kg, respectively. Beyond day 5 of storage, total internal organ disintegration had led to an abnormal increase in OCP residues of liver-like mass. Despite a threefold increase in overall OCP residues by day 9, accumulation of benzene hexachloride (BHC) and heptachlor was sixfold, endrin and DDT were fourfold, aldrin was threefold, and endosulfan and cypermethrin were both twofold. Endosulfan, DDT, endrin, and heptachlor were similarly lost in the gills at a rate of 40%, while aldrin and BHC were also lost at 60 and 30%, respectively. The accumulation of OCP residues in tissues has been attributed to particular types of fatty acid derivatives. The study concluded that while pesticide diffusion to edible tissues can occur during ice storage, the levels observed were well below the allowable limit for endosulfan, endrin, and DDT.

Inhalation bioaccessibility of imidacloprid in particulate matter: Implications for risk assessment during spraying.

Adverse health outcomes due to the inhalation of pesticide residues in atmospheric particulate matter (PM) are gaining global attention. Quantitative health risk assessments of pesticide inhalation exposure highlight the need to understand the bioaccessibility of pesticide residues. Herein, the inhalation bioaccessibility of imidacloprid in PM was determined using three commonly used in vitro lung modeling methods (Artificial Lysosomal Fluid, Gamble Solution, and Simulated Lung Fluid). To validate its feasibility and effectiveness, we evaluated the bioavailability of imidacloprid using a mouse nasal instillation assay. The in vitro inhalation bioaccessibility of imidacloprid was extracted using Gamble Solution with a solid-liquid ratio of 1/1000, an oscillation rate of 150 r/min, and an extraction time of 24 h, showed a strong linear correlation with its in vivo liver-based bioavailability (R2 =0.8928). Moreover, the margin of exposure was incorporated into the inhalation exposure risk assessment, considering both formulations and nozzles. The inhalation unit exposure of imidacloprid for residents was 0.95-4.09 ng/m3. The margin of exposure for imidacloprid was determined to be acceptable when considering inhalation bioaccessibility. Taken together, these results indicate that the inhalation bioaccessibility of pesticides should be incorporated into assessments of human health risks posed by PM particles.

On-site preparation of sandwich plasmonic coupled SERS tape toward pesticide residue determination on food surface.

A sandwich plasmonic coupled surface enhanced Raman spectroscopy (SERS) tape is proposed prepared by peeling the chemical printed silver nanocorals (AgNCs) from Cu sheet with adhesive tape, which can sample targets from food surface and sandwich them between substrates and Cu sheet for SERS detection. The solid-to-solid transformation method for fabricating SERS tapes can effectively avoid the weakening of tape stickiness during the preparation process. The sandwich plasmonic coupled structure of AgNC substrate, targets, and Cu sheet display excellent SERS activity (EF = 1.62 × 107) for sensitive determination of analytes. In addition, due to the high heat conductivity of Cu sheet, the thermal effect of laser irradiation during SERS detection cannot damage the AgNC tapes, which ensures the reproducibility of subsequent quantification. The sandwich plasmonic coupled SERS tape is demonstrated to quantify malachite green (MG) and methyl parathion (MP) with good linear coefficients (> 0.98) by two typical calibration plots under different concentration ranges. The limit of detection (LOD) of the method is 0.17 ng/cm2 and 0.48 µg/cm2 (S/N = 3) for MG and MP. This method can realize the quantitative determination of MP and MG on the surface of fruits and fish scale with recoveries of 93-113%. The satisfactory detection results demonstrate the proposed sandwich plasmonic coupled AgNC tape can be successfully applied to SERS-based point-of-care testing (POCT) for pesticide residue determination, which will provide a new path for designing and constructing SERS tapes.

A risk entropy approach for linking pesticides and soil bacterial communities.

Pesticides play a vital role in ensuring modern agricultural production, but also adversely affecting soil health. Microorganisms are the cornerstone of soil ecology, however, to date, there are few unified standards to measure the risk of soil pesticide residues to soil microbial community. To compensate for this gap, we collected soil samples from 55 orchards and monitored and risk-assessed 165 pesticides to microbial community in the soil. Results showed that a total of 137 pesticides were detected in all samples. Pesticide residues significantly influenced the microbial diversity and community structure in orchard soils, particularly fungicides and herbicides. The risk entropy of each pesticide was calculated in all samples and it was found that 60% of the samples had a "pesticide risk" (Risk quotient > 0.01), where the relative abundance significantly increased in 43 genera and significantly decreased in 111 genera (p < 0.05). Through multiple screens, we finally identified Bacillus and Sphingomonas as the most abundant sensitive genera under pesticide perturbation. The results showed that despite the complexity of the effects of pesticide residues on soils health, we could reveal them by identifying changes in soil bacterial, especially by the differences of microbial biomarkers abundance. The present study could provide new insights into the research strategy for pesticide pollution on soil microbial communities. ENVIRONMENTAL IMPLICATION: The risk of pesticide residues in soil needs to be quantified and standardized. We believe that microorganisms can be used as a marker to indicate soil pesticide residue risk. For this end, we investigated the residues of 165 pesticides in 55 orchard soil samples, calculated pesticide risk entropy and their effects on the soil microbial community. Through multiple analyzing and screening, we ultimately identified that, out of the 154 detected biomarkers, Bacillus and Sphingomonas were the most abundant sensitive genera under pesticide perturbation, which have the potential to be used as key biomarkers of soil microbiomes induced by pesticide perturbation.

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.

A computational and experimental study of cis-trans isomeric pesticides based on collision-induced dissociation of high-resolution mass spectrometry.

RATIONALE: Pesticide isomers are widely available in agricultural production and may vary widely in biological activity, potency, and toxicity. Chromatographic and mass spectrometric analysis of pesticide isomers is challenging due to structural similarities. METHODS: Based on liquid chromatography time-of-flight mass spectrometry, identification of cis-trans isomeric pesticides was achieved through retention time, characteristic fragment ions, and relative abundance ratio. Furthermore, theoretical and basic research has been conducted on the differences in characteristic fragment ions and their relative abundance ratios of cis-trans isomers. On the one hand, the cleavage pathways of six cis-trans isomers were elucidated through collision-induced dissociation to explain different fragment ions of the isomers. On the other hand, for those with the same fragment ions but different abundance ratios, energy-resolved mass spectrometry combined with computational chemical density functional theory in terms of kinetics, thermodynamics, and bond lengths was employed to explain the reasons for the differences in characteristic fragment ions and their abundance ratios. RESULTS: A high-resolution mass spectrometry method was developed for the separation and analysis of cis-trans isomers of pesticides in traditional Chinese medicine Radix Codonopsis, and six pesticide isomers were distinguished by retention time, product ions, and relative abundance ratios. The limits of quantification of the six pesticides were up to 10 µg/kg, and the linear ranges of them were 10-200 µg/kg, with coefficients of determination (R2) > 0.99, which demonstrated the good linearity of the six pesticides. The recoveries of the pesticides at spiked concentrations of 10, 20, and 100 µg/kg reached 70-120% with relative standard deviations ≤20%. CONCLUSIONS: It was demonstrated that the application of the method was well suited for accurate qualitative and quantitative analysis for isomers with different structures, which could avoid false-negative results caused by ignoring other isomers effectively.

Dissipation and Risk Assessment of Propaquizafop in Ginseng under Field Conditions.

Propaquizafop is a highly efficient aryloxy phenoxy propionate chiral herbicide. However, the use of propaquizafop, including its safe use methods, residue patterns, dietary risk assessment, and maximum residue limits, for ginseng, a traditional Chinese medicinal plant, has not been studied. An analytical method was established for the simultaneous determination of propaquizafop and its four metabolites in ginseng soil, fresh ginseng, ginseng plant, and dried ginseng using HPLC-MS/MS. This approach showed good linearity (R2 ranging from 0.9827 to 0.9999) and limit of quantification ranging from 0.01 to 0.05 mg/kg. The intra- and interday recovery rates of this method ranged from 71.6 to 107.1% with relative standard deviation ranging from 1.3 to 23.2%. The method was applied to detect residual samples in the field, and it was found that the degradation of propaquizafop in ginseng plants and soil followed a first-order kinetic equation. R2 was between 0.8913 and 0.9666, and the half-life (t1/2) ranged from 5.04 to 8.05 days, indicating that it was an easily degradable pesticide (T1/2 < 30 days). The final propaquizafop residues in ginseng soil, plants, fresh ginseng, and dried ginseng ranged from 0.017 to 0.691 mg/kg. A dietary risk assessment was conducted on the final propaquizafop residue in fresh and dried ginseng. The results showed that the chronic exposure risk quotient values were less than 100% for fresh and dried ginseng (1.15% for fresh ginseng and 1.13% for dried ginseng). This illustrates that the dietary risk associated with the use of 10% propaquizafop emulsifiable concentrate in ginseng is very low. Thus, applying 750 mL/ha of propaquizafop on ginseng could not pose an unacceptable risk to public health. The results of the present study support the registration of propaquizafop in ginseng.