Residue level and dissipation pattern of spiromesifen in cabbage and soil from 2-year field study

Terminal Residues and Risk Assessment of Spiromesifen and Spirodiclofen in Tomato Fruits

Insecticides are important to increase crop yields, but their overuse has damaged the environment and endangered human health. In this study, residues of spiromesifen and spirodiclofen were determined in tomato fruit using a simple and efficient analytical procedure based on acetonitrile extraction, extract dilution, and UPLC-MS/MS. The linearity range was 1-100 µg/kg and 0.5-100 µg/kg, and the correlation coefficient (R²) and residuals were ≥0.9991 and ≤16.4%, respectively. The limit of determination (LOD) was 0.26 and 0.08 µg/kg, while the limit of quantification (LOQ) was verified at 5 µg/kg. The relative standard deviation of spiked replicates at 5 µg/kg analyzed in one day (RSDr, n = 6) was ≤8.35%, and within three different days (RSDR, n = 18) it was ≤15.85%, with recoveries exceeding 91.34%. The method recovery test showed a satisfactory value of 89.23-97.22% with an RSD of less than 12.88%. The matrix effect was determined after a 4-fold dilution of the raw extract and was -9.8% and -7.2%, respectively. The validated method was used to study the dissipation behavior of the tested analytes in tomato fruit under field conditions. First-order kinetics best described the dissipation rates. The calculated half-lives were 1.49-1.83 and 1.91-2.38 days for spiromesifen and spirodiclofen, respectively, after application of the authorized and doubled authorized doses, indicating that spiromesifen dissipated more rapidly than spirodiclofen. The final residue concentrations of spiromesifen and spirodiclofen were 0.307-0.751 mg/kg and 0.101-0.398 mg/kg, respectively, after two or three applications, and were below the European Union (EU) maximum residue limits. The chronic risk assessment indicates that both insecticides are safe for adult consumers.

A Comprehensive Review of Pesticide Residues in Peppers

Pesticides are chemicals that are used to control pests such as insects, fungi, and weeds. Pesticide residues can remain on crops after application. Peppers are popular and versatile foods that are valued for their flavor, nutrition, and medicinal properties. The consumption of raw or fresh peppers (bell and chili) can have important health benefits due to their high levels of vitamins, minerals, and antioxidants. Therefore, it is crucial to consider factors such as pesticide use and preparation methods to fully realize these benefits. Ensuring that the levels of pesticide residues in peppers are not harmful to human health requires rigorous and continuous monitoring. Several analytical methods, such as gas chromatography (GC), liquid chromatography (LC), mass spectrometry (MS), infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-Vis), and nuclear magnetic resonance spectroscopy (NMR), can detect and quantify pesticide residues in peppers. The choice of analytical method depends on the specific pesticide, that is being tested for and the type of sample being analyzed. The sample preparation method usually involves several processes. This includes extraction, which is used to separate the pesticides from the pepper matrix, and cleanup, which removes any interfering substances that could affect the accuracy of the analysis. Regulatory agencies or food safety organizations typically monitor pesticide residues in peppers by stipulating maximum residue limits (MRLs). Herein, we discuss various sample preparation, cleanup, and analytical techniques, as well as the dissipation patterns and application of monitoring strategies for analyzing pesticides in peppers to help safeguard against potential human health risks. From the authors' perspective, several challenges and limitations exist in the analytical approach to monitoring pesticide residues in peppers. These include the complexity of the matrix, the limited sensitivity of some analytical methods, cost and time, a lack of standard methods, and limited sample size. Furthermore, developing new analytical methods, using machine learning and artificial intelligence, promoting sustainable and organic growing practices, improving sample preparation methods, and increasing standardization could assist efficiently in analyzing pesticide residues in peppers.

Simultaneous determination of spirodiclofen, spiromesifen, and spirotetramat and their relevant metabolites in edible fungi using ultra-performance liquid chromatography/tandem mass spectrometry

A fast, sensitive, and reliable analytical method was developed and validated for simultaneous identification and quantification of spirodiclofen, spiromesifen, and spirotetramat and their relevant metabolites in edible fungi by ultra-performance liquid chromatography/tandem mass spectrometry (UHPLC–MS/MS). First, sample extraction was done with acetonitrile containing 1% formic acid followed by phase separation with the addition of MgSO₄:NaOAc. Then, the supernatant was purified by primary secondary amine (PSA), octadecylsilane (C18), and graphitized carbon black (GCB). The linearities of the calibrations for all analytes were excellent (R² ≥ 0.9953). Acceptable recoveries (74.5–106.4%) for all analytes were obtained with good intra- and inter- relative standard deviations of less than 14.5%. The limit of quantification (LOQs) for all analytes was 10 μg kg⁻¹. For accurate quantification, matrix-matched calibration curve was applied to normalize the matrix effect. The results indicated that the method was suitable for detecting the three acaricides and their relevant metabolites in edible fungi.

Residue behaviors and risk assessment of flonicamid and its metabolites in the cabbage field ecosystem

Flonicamid, a novel selective systemic pesticide, can effectively control a broad range of insect pests. However, the dissipation behaviors and the terminal residues of flonicamid and its metabolites in some crops and soils remain unclear. Herein, an easy, sensitive and reliable method using a modified QuEChERS extraction coupled with LC-MS/MS for the simultaneous analysis of flonicamid and its metabolites in cabbage and soil was developed. Based on this method, the dissipation behaviors of flonicamid and its metabolites as well as their persistence in cabbage and soil during harvest were investigated. Flonicamid degraded rapidly, and the half-lives of flonicamid only and total residues (the sum of flonicamid and its metabolites) were 1.49-4.59 and 1.97-4.99 days in cabbage, and 2.12-7.97 and 2.04-7.62 days in soil, respectively. When 50% flonicamid WG was sprayed once or twice at the recommended dose and 1.5-fold the recommended dose, the highest residues of total flonicamid in cabbage and soil from different pre-harvest intervals (3, 7 and 14 days) were 0.070 and 0.054 mg kg^-1, respectively. The risk quotient (RQ) of flonicamid based on the consumption data from China was below 16.84%, indicating that the use of flonicamid is non-hazardous to humans. These results could not only guide the safe and responsible use of flonicamid in agriculture but also help the Chinese government establish the maximum residue level (MRL) for flonicamid in cabbage.

Residue and distribution of triforine in different cultivars and fruit periods of watermelon under field conditions

The dissipation of triforine in the immature and mature fruit periods was investigated under field conditions. Residue levels of triforine in watermelon were determined by gas chromatography with an electron capture detector (GC-ECD). The decline curves of triforine residues in the watermelon corresponded with first-order kinetics. The half-lives of triforine in Dark Belle and Shiny Boy were 2.10-2.57 days and 2.31-2.67 days respectively. Meanwhile, the half-lives of triforine in the immature and mature fruit periods were 1.69-2.04 days and 2.89-3.85 days, respectively. In the terminal residue experiment, the terminal residues of triforine in the watermelon flesh and peel were below 0.01 mg/kg to 0.05 mg/kg and 0.03 mg/kg to 0.36 mg/kg, respectively. The dissipation rates of triforine varied in different cultivars of watermelon, and even in the same cultivar, the half-lives of triforine significantly varied in the different fruit periods. Although triforine is a fungicide within the suction, the terminal residues in the peel and flesh were very significant.

Dissipation of spiromesifen and spiromesifen-enol on tomato fruit, tomato leaf, and soil under field and controlled environmental conditions

Dissipation of spiromesifen and its metabolite, spiromesifen-enol, on tomato fruit, tomato leaf, and soil was studied in the open field and controlled environmental conditions. Sample preparation was carried out by QuEChERS method and analysis using LC-MS/MS. Method validation for analysis of the compounds was carried out as per "single laboratory method validation guidelines." Method validation studies gave satisfactory recoveries for spiromesifen and spiromesifen-enol (71.59-105.3%) with relative standard deviation (RSD) < 20%. LOD and LOQ of the method were 0.0015 μg mL^-1 and 0.005 mg kg^-1, respectively. Spiromesifen residues on tomato fruits were 0.855 and 1.545 mg kg^-1 in open field and 0.976 and 1.670 mg kg^-1 under polyhouse condition, from treatments at the standard and double doses of 125 and 250 g a.i. ha^-1, respectively. On tomato leaves, the residues were 5.64 and 8.226 mg kg^-1 in open field and 6.874 and 10.187 mg kg^-1 in the polyhouse. In soil, the residues were 0.532 and 1.032 mg kg^-1 and 0.486 and 0.925 mg kg^-1 under open field and polyhouse conditions, respectively. The half-life of degradation of spiromesifen on tomato fruit was 6-6.5 days in the open field and 8.1-9.3 days in the polyhouse. On tomato leaves, it was 7-7.6 and 17.6-18.4 days and in soil 5.6-7.4 and 8.4-9.5 days, respectively. Metabolite, spiromesifen-enol, was not detected in any of the sample throughout the study period. Photodegradation could be the major route for dissipation of spiromesifen in the tomato leaves, whereas in the fruits, it may be the combination of photodegradation and dilution due to fruit growth. The results of the study can be utilized for application of spiromesifen in plant protection of tomato crop under protected environmental conditions.

Residue level and dissipation of carbendazim in/on pomegranate fruits and soil

Carbendazim is widely used on pomegranate for control of a large number of fungal diseases. Its residue levels in/on pomegranate fruits and soil were evaluated under field conditions. The quick, easy, cheap, effective, rugged, and safe (QuEChERS) method in conjunction with liquid-chromatography mass spectrometry was used for analysis of carbendazim. Recovery of carbendazim was within 78.92-96.28 % and relative standard deviation within 3.8-10.9 % (n = 6). Carbendazim residues on pomegranate fruits dissipated at the half lives of 17.3 and 22.8 days from treatments at 500 and 1000 g active ingredient (a.i.) ha(-1), respectively. Its residues in pomegranate aril were highest on the tenth day and reduced thereafter. The residue level of carbendazim on pomegranate whole fruits from standard dose treatment was less than the EU maximum residue limit (MRL) of 0.1 mg kg(-1) at harvest. The carbendazim residues were <LOQ in the aril and field soil at harvest. The pre-harvest intervals (PHIs) of carbendazim on pomegranate were 65.4 and 103.4 days. The results of this study can be used to determine the judicious use of carbendazim for plant protection of pomegranate crop.