Determination of Sulfoxaflor in Animal Origin Foods Using Dispersive Solid-Phase Extraction and Multiplug Filtration Cleanup Method Based on Multiwalled Carbon Nanotubes by Ultraperformance Liquid Chromatography/Tandem Mass Spectrometry

Optimization of a QuEChERS-LC-MS/MS method for 51 pesticide residues followed by determination of the residue levels and dietary intake risk assessment in foodstuffs

A modified QuEChERS purification-liquid chromatography-tandem mass spectrometry method has been developed to determine 51 pesticide residues with newly established maximum residue limits (MRLs) in foodstuffs. Samples were extracted with acetonitrile under citrate-buffered conditions and purified using a modified QuEChERS method employing hydroxylated MWCNTs, SAX, and C18. The limits of quantification ranged from 0.2 to 9.8 µg/kg. Recoveries in ten different foodstuffs ranged from 70.2% to 117.9%, with relative standard deviations between 2.3% and 19.9% at three spiking levels. This method was applied to analyze 352 market samples, detecting 14 pesticides in 97 samples. Notably, Afidopyropen, cyantraniliprole, and fluxapyroxad residues in vegetables exhibited a consistent pattern of higher levels in the spring and winter and lower levels in the summer and autumn. Moreover, the risk assessments for acute and chronic dietary exposure to the 14 detected pesticides indicated that the %ADI and %ARfD were well below 100%.

[Determination and Residue Survey of Novel Nicotinic AcetylcholineReceptor Modulator Pesticides in Brown Rice by LC-MS/MS]

Nicotinic acetylcholine receptors (nAChRs) are neurotransmitter receptors found in the nervous system of many organisms, including humans. Neonicotinoid pesticides act as nAChRs modulators that affect neurotransmission. Due to toxicity effects, their use has been restricted. However, a new class of modulators (nAChRMs) have been developed, but analytical methods for the detection of residues of these new pesticides in agricultural crops have not been established. Therefore, this study aimed to develop and validate an accurate determination method for novel nAChRMs, such as sulfoxaflor, flupyradifurone, flupyrimin, and triflumezopyrim in brown rice using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The method was applied to commercially available brown rice samples from Tokyo, Japan. Target analytes were extracted with acetonitrile, cleaned with GC/PSA, and then cleaned again with MonoSpin PBA. In accordance with the method validation guidelines for residual pesticides in foods, the performance characteristics were evaluated, with trueness ranging from 86.3% to 98.2%, repeatability of less than 6.5% relative standard deviation (RSD), and within-laboratory reproducibility of less than 6.5% RSD. These results indicate that the developed method can be applied to residue surveillance of target analytes using solvent standard calibration curves. By applying the developed method to 53 brown rice samples commercially available in Tokyo, sulfoxaflor residues were found in two samples at concentrations of 3.7 and 21.9 ng/g. This is the first report of the detection of sulfoxaflor residues in domestic agricultural products.

Sulfoxaflor induces immunotoxicity in zebrafish (Danio rerio) by activating TLR4/NF-κB signaling pathway

Sulfoxaflor is an insecticide that is widely used and affects the nervous system of sucking pests. However, studies on the molecular mechanism of the toxicity of sulfoxaflor to non-target species are limited. Zebrafish (Danio rerio) was used as an experimental subject in this study. Zebrafish embryos were exposed to 20, 25, and 30 mg/L sulfoxaflor solution to detect hatchability, mortality, heart rate, neutrophil count, oxidative stress, and expression of genes related to apoptosis and immune inflammation. The results showed that zebrafish embryos exposed to sulfoxaflor solution increased mortality and growth retardation, and the number of innate immune cells decreased significantly. In addition, the expression levels of apoptotic and proapoptotic genes increased significantly, and oxidative stress-related indexes changed significantly. Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway was further studied, and the interleukin 6 (IL-6), interleukin 1 beta (IL-1β), cyclooxygenase-2 (COX2), tumor necrosis factor-alpha (TNF-α), TLR4, and myeloid differentiation primary response 88 (MYD88) gene expression levels were significantly up-regulated. We used small molecule inhibitor QNZ for the rescue experiment and detected the expression of relevant target proteins in the QNZ signaling pathway. QNZ reduced the expression of TLR4/NF-κB signaling pathway-related protein NF-κB p65 in the cytoplasm and nucleus and rescued the number of innate immune cells. In summary, sulfoxaflor may induce developmental toxicity and immunotoxicity in zebrafish by activating the TLR4/NF-κB signaling pathway, which provides a basis for further studies on the molecular mechanism of sulfoxaflor action in the aquatic ecosystem and the development and utilization of QNZ.

Preparation of an efficient magnetic nano-sorbent based on modified cellulose and carboxylated carbon nano-tubes for extraction of pesticides from food and agricultural water samples before GC-FID analysis

This paper reports the direct synthesis approach of carboxamide functionalized magnetic nano-composite named Fe₃O₄@SiO₂-NH₂@dialdehyde cellulose (DAC)@CNT-COOH as an effectual sorbent for the co-extraction of seven agricultural insecticides and herbicides from vegetable, fruit, and water samples using the magnetic dispersive micro-solid-phase extraction procedure. Under the optimized extraction conditions (sorbent amount: 18.1 mg; desorption time: 6.5 min; desorption solvent volume: 185 μL; desorption solvent: acetonitrile; extraction time: 9.5 min; pH of sample solution: 7.0, and salt content: 5.0 % w/v sodium chloride), good linearity within the range 0.5-1200 ng/mL (R² ≥ 0.998) was achieved. Extraction efficiencies were in the range 63.4-84.1 %, the limits of detection were 0.08-1.0 ng/mL, and acceptable relative recoveries (87.6-103.8 %), and precisions were also achieved (RSDs < 6.8 %, n = 3). Ultimately, the obtained results showed that the developed method could be applied to determine trace amounts of desired analytes in various agricultural water and food samples.

Evaluating sulfoxaflor residues in pig tissues using animal modeling

Maximum residue limits (MRL) for pesticides in feed have been set to protect public health and produce safe livestock products. In vivo experiments to establish MRL are essential, as livestock are commonly used to obtain reliable In vivo quantitative information. Here, we aimed to evaluate whether small laboratory animals can replace or reduce monogastric livestock in experiments to quantify pesticide residues In vivo after oral consumption through feed. First, 24 pigs and rats were randomly assigned to four groups and fed 0, 3, 9, or 30 mg/kg of sulfoxaflor. After four weeks, serum, muscle, fat, liver, kidney, and small intestine samples were collected, and sulfoxaflor residues were analyzed using liquid chromatography - tandem mass spectrometry. Sulfoxaflor residues in pig tissues were significantly correlated with those in rat tissues. Model equations were formulated based on the residual sulfoxaflor amount in pig and rat tissues. The calculated and measured sulfoxaflor residues in pigs and rats showed more than 90% similarity. Sulfoxaflor did not affect body weight gain, feed intake, or the feed conversion ratio. Therefore, we concluded that pesticide residue quantification in vivo to establish MRL could be performed using small laboratory animals instead of livestock animals. This would contribute to obtaining In vivo pesticide residue information and reducing large-scale livestock animal experiments.

Dissipation and residue analysis of novel nematicide trifluorocide in ginseng and soil using modified QuEChERS method coupled with HPLC-MS/MS

In the present study, an analytical method that combined a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and high-performance liquid chromatography coupled with tandem mass spectrometry was developed to determine trifluorocide in fresh and dried ginseng roots, plants (stems and leaves), and soil. At three spiked levels (0.01, 0.1, and 1.0 mg kg^-1), the mean recoveries (n = 15) of trifluorocide from fresh and dried ginseng roots, plants, and soil were in the range of 95.6 - 109.7%, with relative standard deviations less than 10.0%. The limits of quantitation of different matrices were determined to be 0.01 mg kg^-1. Dissipation and residue study of trifluorocide was conducted in ginseng cultivation ecosystems in Northeast China. The t_1/2 (half-life) of trifluorocide in ginseng fresh roots, plants, and soil were 8.3-13.1 days, 7.4-10.9 days, and 8.8-10.6 days, respectively. The terminal residues of trifluorocide in ginseng fresh roots were less than 0.01 mg kg^-1 after 35 days of trifluorocide application. This study could be beneficial in residue analysis and assist in the scientific application of trifluorocide during ginseng cultivation.

Determination of Six Eugenol Residues in Aquatic Products by Gas Chromatography-Orbitrap Mass Spectrometry

Eugenol compounds are widely used in the circulation and transportation of fresh aquatic products because of their good anesthetic effects. However, some studies have shown that eugenol compounds are potential carcinogens. Therefore, in order to ensure the edible safety of aquatic products, eugenol compounds in aquatic products need to be screened quickly. A method for determination of six eugenol residues in aquatic products was established by multiplug filtration cleanup (m-PFC), combined with gas chromatography-Orbitrap mass spectrometry (Orbitrap GC-MS). Samples were ultrasonically extracted with acetonitrile, and the extracts were frozen at −18°C for 1 h, then purified with the m-PFC column, and detected by Orbitrap GC-MS in full scan mode. The results showed the linear relationships for six eugenols were good in the range of 0.001–0.1 μg/mL, and the correlation coefficients (R2) were above 0.9950. The limits of detection (LODs) were 2–10 μg/kg, and the limits of quantitation (LOQs) were 5–20 μg/kg. The average recoveries at the spiked levels of 5–200 μg/kg were in the range of 76.4%–105.1%, with relative standard deviations (RSDs) of 1.2%–7.5%. Eighty aquatic products were detected by this method, of which only eugenol was detected in 12 samples, and eugenol and isoeugenol were detected in two samples at the same time. The other eugenol compounds were not detected in any sample. The detection rate of positive samples was 17.5%. The method is simple, accurate, and suitable for the rapid screening of eugenol compounds in aquatic products.

Stereoselective separation of sulfoxaflor by electrokinetic chromatography and applications to stability and ecotoxicological studies

An Electrokinetic Chromatography method was developed for the stereoselective analysis of sulfoxaflor, a novel sulfoximine agrochemical with two chiral centers. A screening with fourteen negatively charged CDs was performed and Succinyl-β-CD (Succ-β-CD) was selected. A 15 mM concentration of this CD in a 100 mM borate buffer (pH 9.0), using an applied voltage of 20 kV and a temperature of 15 °C made possible the baseline separation of the four stereoisomers of sulfoxaflor in 13.8 min. The evaluation of the linearity, accuracy, precision, LODs and LOQs of the method developed showed its performance to be applied to the analysis of commercial agrochemical formulations, the evaluation of the stability of sulfoxaflor stereoisomers under biotic and abiotic conditions, and to predict, for the first time, sulfoxaflor toxicity (using real concentrations instead of nominal concentrations), on two non-target aquatic organisms, the freshwater plant, Spirodela polyrhiza, and the marine bacterium, Vibrio fischeri.

Review of sample preparation methods for chromatographic analysis of neonicotinoids in agricultural and environmental matrices: From classical to state-of-the-art methods

This review specifically examines the development of sample preparation methods for residue analyses of neonicotinoid insecticides in agricultural and environmental matrices. Pesticide residue analysis is fundamentally important to ensure the safety of foods and processed foods of plant and animal origin, and to preserve the environment, particularly soil and water. For the development of pesticide residue analysis, the sample preparation process is an important key to maximizing the analytical performance of highly sensitive and accurate chromatographic instruments and to acquiring reliable analytical results. This review outlines sample preparation methods that have been proposed to date for extraction of neonicotinoids that might remain in a complicated sample matrix in quantitatively trace amounts, and for cleaning up, to the greatest extent possible, the interfering components that coexist in the sample extract.

Simultaneous determination of the herbicide bixlozone and its metabolites in plant and animal samples by liquid chromatography-tandem mass spectrometry

Tracing the herbicide bixlozone and its metabolites in food is necessary to assess their risks to human health. In the study, a rapid and effective analytical method using the quick, easy, cheap, effective, rugged, and safe method for the simultaneous determination of bixlozone and its metabolites (2,4-dichlorobenzoic acid, 3-hydroxy-propanamide-bixlozone, and 5'-hydroxy-bixlozone) in plant and animal samples (tomato, cucumber, apple, wheat flour, meat, milk, and egg) was developed based on ultra high performance liquid chromatography-tandem mass spectrometry. The method was validated based on the linearity (R²  > 0.99), sensitivity (limit of quantification = 0.01 mg/kg), recovery (70.2-115.1%), and precision (intraday 1.2-17.6%, interday 0.3-16.0%). Detection was achieved within 6.0 min. The method is reliable for the determination of four target compounds in all seven matrices. The satisfactory validation criteria and successful application show that the proposed methodology is suitable for the detection of four target compounds in real matrices.

Preparative isolation of the major metabolite NK-1375 of diamide insecticide cyclaniliprole and its application to pertinent residue analysis in plant-origin foods using UHPLC-MS/MS

NK-1375 is a major metabolite of the diamide insecticide cyclaniliprole (CYCP) with toxicological significance. It is formed in various transformation pathways of CYCP, including photolysis and plant metabolism. In the present study, NK-1375 was produced employing the liquid-phase photolysis of CYCP followed by isolation using preparative liquid chromatography. The structure of the isolated substance was confirmed using MS and ¹ H NMR spectroscopy, and its purity was measured to be 95.9% using HPLC. As its application, a residue analysis method was first developed for the simultaneous determination of CYCP and NK-1375 in six representative plant-origin foods using fast multi-plug filtration cleanup and UHPLC-MS/MS. Excellent linearity (r > 0.999) was obtained over the calibration range from 0.001 to 0.1 μg mL^-1 . The recoveries (intra-day and inter-day) of CYCP and NK-1375 from different matrices ranged from 74 to 112%, with corresponding relative standard deviations less than 13%. The limits of quantitation of these two compounds were defined at 0.01 mg kg^-1 . This study can be useful for the subsequent analytical or toxicological research on this important pesticide metabolite.

Determination of 12 Carbamate Insecticides in Typical Vegetables and Fruits by Rapid Multi-Plug Filtration Cleanup and Ultra-Performance Liquid Chromatography/Tandem Mass Spectrometry Detection

A multiresidue method for determining 12 carbamate pesticides in purple cabbage, orange, watermelon, cucumber, cowpea and Lactuca sativa L. employing multi-plug filtration cleanup (m-PFC) and ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) was developed. M-PFC was carried out by cleanup at dispersive solid phase extraction (d-SPE), one m-PFC tip-filtration, two m-PFC tip-filtration and other methods (1-3 m-PFC cleanups). Results demonstrated that filtration simplified the cleanup method compared with d-SPE and other m-PFC methods (1-3 m-PFC cleanups). The method validation results showed that the method was linear, selective and accurate. The limits of quantification (LOQs) were 0.05-5.0 μg/kg, and the recoveries were in the range of 70.1-119.9% in different matrices. Although matrix effects were observed, they were successfully compensated using matrix-matched calibration. Finally, the developed method was successfully applied to detect pesticides in real samples.

Simultaneous Enantioselective Determination of Two New Isopropanol-Triazole Fungicides in Plant-Origin Foods Using Multiwalled Carbon Nanotubes in Reversed-Dispersive Solid-Phase Extraction and Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry

A simple and sensitive enantiomeric analytical method was established for the determination of two new isopropanol-triazole fungicides mefentrifluconazole and ipfentrifluconazole in plant-origin foods using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The best enantioseparation of the four target stereoisomers was achieved on a Chiral MX(2)-RH column within 7 min by reversed-phase liquid chromatography, which is a significant improvement in the resolution of different chiral compounds under one set of conditions. A simple and effective pretreatment procedure was developed for the extraction and purification of the two target chiral fungicides using reversed-dispersive solid-phase extraction (r-DSPE) with multiwalled carbon nanotubes (MWCNTs). The influence of the type and amount of MWCNTs on the purification efficiencies and recoveries was evaluated. The mean recoveries for all four stereoisomers were in the range of 76.9-91.2%, with relative standard deviation (RSD) values below 7.2%. The limit of quantification (LOQ) of all stereoisomers of mefentrifluconazole and ipfentrifluconazole was 5 μg/kg for all tested matrixes. The results of the method validation and real samples analysis confirm that the established method is efficient and reliable for the enantiomeric determination of mefentrifluconazole and ipfentrifluconazole in plant-origin food samples.

Simultaneous Determination of Five Diamide Insecticides in Food Matrices Using Carbon Nanotube Multiplug Filtration Cleanup and Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry

In this study, an analytical method was developed and validated for simultaneous determination of five diamide insecticides (chlorantraniliprole, cyantraniliprole, flubendiamide, cyclaniliprole, and tetrachlorantraniliprole) in food matrices. Determination of the latter two diamide compounds is first reported. Samples were cleaned up by multiplug filters containing carbon nanotubes (CNT) or hydrophilic-lipophilic balanced copolymers (HLB) and classic dispersive solid phase extraction (d-SPE) procedures, respectively. The CNT multiplug filter performed the best in terms of process rapidity and cleanup efficiency; thus, it was finally chosen for sample cleanup. Instrumental analysis was completed in 5 min using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Mean recoveries of the five diamides ranged from 84.3 to 110.0%, with intraday and interday relative standard deviations (RSD) of less than 13.5%. Limits of quantitation (LOQ) of all analytes ranged from 0.005 to 0.01 mg kg^-1 in different matrices. The results indicate this method is reliable for monitoring the five diamide insecticides in various foods.

Lethal Toxicity and Sublethal Metabolic Interference Effects of Sulfoxaflor on the Earthworm ( Eisenia fetida)

Testing for effects of pesticides on nontarget organisms is an integral part of ecological risk assessment. In the present study, the acute toxicity of sulfoxaflor to earthworms was evaluated using an artificial soil toxicity test, and sublethal effects were assessed through oxidative stress and metabolomics. Sulfoxaflor is a supertoxic pollutant to earthworms that easily bioaccumulates in earthworms, and contains LC₂, LC₁₀, and LC₅₀ values of 0.08 (0.04-0.13), 0.19 (0.11-0.25), and 0.54 (0.45-0.65) mg/kg, respectively. Sublethal doses of sulfoxaflor resulted in oxidative damage to earthworms in which antioxidant enzymatic activities including SOD, CAT, and GST were significantly inhibited and MDA content accumulated. Metabolomics analysis suggested that the energy metabolism and the urea cycle in earthworms were significantly activated, while nucleotide metabolism was depressed, which could cause DNA damage. The results suggest earthworms have the potential to be a new entry point for sulfoxaflor into the wildlife food chain. Since earthworms significantly contribute to soil function and ecosystems, the high safety risks of sulfoxaflor to the earthworm could extend to the environment. In view of these findings, more attention should be given to the risks sulfoxaflor poses to the environment through its effects on earthworms.

Determination of Ochratoxin A contamination in grapes, processed grape products and animal-derived products using ultra-performance liquid chromatography-tandem mass spectroscopy system

We developed a sensitive and rapid analytical method to determine the level of Ochratoxin A contamination in grapes, processed grape products and in foods of animal origin (a total of 11 different food matrices). A pretreatment that followed a "quick, easy, cheap, effective, rugged, and safe" protocol was optimized to extract Ochratoxin A from the matrices, and the extracted Ochratoxin A was then detected with the use of a highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry system. Good linearities of Ochratoxin A were obtained in the range of 0.1-500 µg L-1 (correlation coefficient (R2) > 0.9994 in each case). Mean recovery from the 11 matrices ranged from 70.3 to 114.7%, with a relative standard deviation ≤19.2%. The method is easy to use and yields reliable results for routine determination of Ochratoxin A in food products of grape and animal origin. In store-purchased foods and foods obtained from the field and wholesale suppliers, the Ochratoxin A concentration ranged from undetectable to 10.14 µg kg-1, with the more contaminated samples being mainly those of processed grape products. Our results indicate that the necessity for regulation of and supervision during the processing of grape products.

Simultaneous detection of sulfoxaflor and its metabolites, X11719474 and X11721061, in lettuce using a modified QuEChERS extraction method and liquid chromatography-tandem mass spectrometry

An analytical method has been developed to quantify the residual levels of sulfoxaflor and its metabolites (X11719474 and X11721061) in/on cultivated lettuce grown under greenhouse conditions. Samples were extracted and purified using a quick, easy, cheap, effective, rugged, and safe 'QuEChERS' method (original version) following systematic method optimization and were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Good linearity with coefficient of determination ≥0.9930 was obtained and the limits of detection (LOD) and quantification (LOQ) were in the ranges of 0.003-0.006 and 0.01-0.02 mg/kg, respectively. The recovery rates of both the parent compound and its metabolites (fortified at 10 and 50× the LOQ) estimated from six replicates ranged between 81.9 and 115.5% with a relative standard deviation <12%. The validated method was applied to field-incurred samples (collected over 7 days) sprayed once or twice with a water-dispersible granule formulation. Notably, a substantial reduction in rate was observed after 3 days and the half-life was short, only 1.5 days. The developed method is simple and versatile and can be used for various leafy vegetables.

Approach for Pesticide Residue Analysis for Metabolite Prothioconazole-desthio in Animal Origin Food

Food safety problems such as damage to immune, nervous, and endocrine systems leading to cancer and malformations have received increasing attention. To achieve the maximum residue limits, the most discussed method of high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is widely used with a advantage of high precision and resolution. Prothioconazole is a broad-spectrum thiocarbamate fungicide. It can rapidly metabolize to prothioconazole-desthio in different matrixes. Rapid and effective methods for the determination of prothioconazole-desthio in five kinds of different animal food were developed. Samples were extracted with acetonitrile or acetonitrile/water and determined by HPLC-MS/MS. The limit of detection and limit of quantification values of prothioconazole-desthio were 0.015 and 0.05 mg/kg for porcine liver and kidney, 0.0015 and 0.005 mg/kg for pork, and 0.003 and 0.01 mg/kg for eggs, together with 0.0012 and 0.004 mg/kg for milk of the detected method, respectively. A good linear regression trend can be observed in a certain concentration range for all of the animal food. At fortified levels, recoveries were between 83.6 and 105%, with relative standard deviations of 1.5-10.3%. A sample survey of 150 samples with 30 samples for each kind of animal food across the country was conducted and found that there was no prothioconazole-desthio detected in all samples.