Monitoring hexythiazox residues in vegetables using LC-MS/MS: Dissipation kinetics, terminal residues, risk assessment, and washing efficiency

A commercial formulation, 37% dispersible oil suspension (DOS) (fomesafen, clomazone, and clethodim), is being registered in China to control annual or perennial weeds in soybean fields. In this paper, a liquid chromatography tandem mass spectrometry method with QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation was developed for the simultaneous determination of fomesafen, clomazone, clethodim, and its two metabolites (CSO and CSO2) in soybean, green soybean, and soybean straw samples. The mean recoveries of our developed method for the five analytes in three matrices were ranged from 71% to 116% with relative standard deviations (RSDs) less than 12.6%. The limits of quantification (LOQs) were 0.01 mg/kg in soybean, 0.01 mg/kg in green soybean, and 0.02 mg/kg in soybean straw while the limits of detection (LODs) ranged from 0.018 to 0.125 μg/kg for these five analytes. The highest final residual amount of CSO2 in green soybean samples (0.015 mg/kg) appeared in Anhui, and the highest in soybean straw samples was 0.029 mg/kg in Guangxi, whilst the terminal residues of fomesafen, clomazone, clethodim and CSO were lower than LOQs (0.01 mg/kg) in all samples. Furthermore, these terminal residues were all lower than the maximum residue limits (MRLs) set by China (0.1 mg/kg for fomesafen and clethodim, 0.05 mg/kg for clomazone) at harvest. Additional chronic dietary risk was evaluated using a risk quotients (RQs) method based on Chinese dietary habits. The chronic dietary exposure risk quotients were 4.3 for fomesafen, 0.12 for clomazone, and 19.3 for clethodim, respectively, which were significantly lower than 100. These results demonstrated that the dietary exposure risk of fomesafen, clomazone, and clethodim used in soybean according to good agricultural practices (GAP) was acceptable and would not pose an unacceptable health risk to Chinese consumers. These results not only offer insight with respect to the analytes, but also contribute to environmental protection and food safety.

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 within78.92-96.28% 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 22.8days from treatments at 500 and 1000g 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 0.1mgkg(-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 103.4days. The results of this study can be used to determine the judicious use of carbendazim for plant protection of pomegranate crop.

This study investigates the dissipation kinetics, terminal residues, and dietary risk assessment of metrafenone in tomatoes and cucumbers cultivated under greenhouse conditions in the Khubash governorate, Najran region, Saudi Arabia. Residue analysis was performed using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with acetonitrile-based extraction. The method demonstrated excellent linearity (R 2 = 0.9981 and 0.9946 for tomatoes and cucumbers, respectively), low limits of detection (LOD: 0.0002 mg kg-1 and 0.0003 mg kg-1, respectively), and limits of quantification (LOQ: 0.0025 mg kg-1 for both matrices). Recovery rates ranged from 93.6% to 98.1% and 92.7% to 99.7% for tomatoes and cucumbers, respectively, with relative standard deviations (RSDs) below 6%, ensuring method accuracy. Precision analysis demonstrated intra-day (RSDr) and inter-day (RSDR) repeatability below 16% for both matrices, confirming the method's repeatability. Matrix effects were minimal, with values of -6.71% and -4.15% for tomatoes and cucumbers, respectively, indicating negligible signal suppression. The dissipation followed first-order kinetics, with half-lives of 1.93-1.96 days and 1.61-1.67 days, respectively. The pre-harvest interval (PHI) was estimated at 1.18-1.56 days for tomatoes and 1.37-2.68 days for cucumbers. Terminal residues varied based on application rates and spray frequency, with some exceeding maximum residue limits (MRLs) at early intervals before declining to safe levels. Chronic dietary risk assessment confirmed that the chronic hazard quotient (HQc) values remained significantly below the safety threshold of 100%, indicating no significant health risks. These findings provide essential data for determining appropriate PHIs and ensuring food safety compliance in commercial crop production.

Residue analysis of emamectin benzoate and lufenuron in cabbage matrices and soil was developed using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and ultra high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with 1% acetic acid in acetonitrile (v/v) or 1% acetic acid in acetonitrile/water (5:1, v/v) and cleaned up by dispersive solid-phase extraction. Mean recoveries and relative standard deviations (RSDs) in all samples ranged 87.8-100.0 % and 3.6-12.6% for emamectin benzoate and 87.8-104.8 % and 6.2-11.5% for lufenuron, respectively. The validated method was used to evaluate the dissipation rate of emamectin benzoate and lufenuron in cabbage and soil as well as the residual levels in harvested cabbage and soil at different preharvest intervals (PHI). The half-lives of emamectin benzoate and lufenuron were 1.08-2.70 and 1.74-5.04 days in cabbage, and 1.42-4.01 and 0.94-6.18 days in soil, respectively. The terminal residues were below the China maximum residue limits (MRLs) at 3 days for emamectin benzoate (0.1 mg kg(-1)) and European Union MRLs at 5 days for lufenuron (0.5 mg kg(-1)), which suggested that 5 days could be recommended as the PHI for the commercial formulation of emamectin benzoate and lufenuron application in the Chinese cabbage field.

The residue levels of fluazinam in root mustard were investigated by using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique with ultra-performance liquid chromatography tandem mass spectrometry. Samples of leaf and root mustard were analyzed. The recoveries of fluazinam were 85.2-110.8% for leaf mustard with the coefficient of variation of 1.0-7.2%, and 88.8-93.3% for root mustard with the coefficient of variation of 1.9-12.4%. The suspension concentrate formulation of fluazinam was applied on root mustard at 262.5g a.i. ha-1 in accordance with good agricultural practice (GAP), respectively. After the final application, the root mustard samples were collected at 3, 7, and 14days. Fluazinam residues in root mustard were less than 0.01-0.493mgkg-1. The dietary risk of fluazinam was predicted by comparing intake amounts with the toxicological data, namely acceptable daily intake (ADI) and acute reference dose (ARfD). The risk quotient (RQ) was 72.2-74.3%, for ordinary consumers, which showed negligible risk. According to the maximum residue limit (MRL) and dietary risk assessment, it is suggested that the pre-harvest interval (PHI) of 3days; meanwhile, the MRL of 2mgkg-1 was suggested for fluazinam in root mustard, which indicates that the dietary risk of fluazinam 500g L-1 suspension concentrate (SC) with the recommended usage on root mustard is negligible. This study provided basic data on the use and safety of fluazinam in root mustard to help the Chinese government formulate a maximum residue level for fluazinam in root mustard.

The persistence of combination formulation of fluopyram 200 + tebuconazole 200-400 SC was evaluated across different agro-climates in India for the management of fungal diseases in two commercially important fruit crops, mango and pomegranate. The residues were extracted using quick easy cheap effective rugged and safe (QuEChERS) method and quantification was done on liquid chromatography-tandem mass spectrometry (LC-MS/MS). The fungicide degradation followed 1st-order kinetics and the half-lives were 2.9-6.4days for mango, and 3.5-7.4days for pomegranate for both the fungicides. On the basis of Organisation for Economic Co-operation and Development (OECD) maximum residue limit (MRL) calculation, 1.0mgkg-1 MRL was obtained for fluopyram while for tebuconazole, it was 0.5mgkg-1 on mango, at the pre-harvest interval (PHI) of 5days. For pomegranate, the respective MRLs were 1.0mgkg-1 and 0.7mgkg-1 at PHI of 7days. The dietary risk assessment study indicated that % acceptable daily intake (% ADI) and % acute reference dose (% ARfD) were much lower than 100; thus, the application of fluopyram and tebuconazole on mango and pomegranate is unlikely to present public health concern.

Method validation and dissipation kinetics of four herbicides in maize and soil using QuEChERS sample preparation and liquid chromatography tandem mass spectrometry

Thiamethoxam is widely used to control pests in Chinese kale, popularly consumed leafy vegetables. The potential risk to the environment and human health has aroused much public concern. Therefore, it is important to investigate the degradation behavior, residue distribution and dietary risk assessment of thiamethoxam in Chinese kale. A sensitive analytical method for determination of thiamethoxam and its metabolite clothianidin residue in Chinese kale was established and validated through a quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The recoveries were 85.4-101.2% for thiamethoxam and 79.5-108.1% for clothianidin, with the relative standard deviations (RSDs) of 0.9-10.2% and 1.8-6.0%, respectively. For the dissipation kinetics, the data showed that thiamethoxam in Chinese kale was degraded with the half-lives of 4.1 to 4.5 days. In the terminal residue experiments, the residues of thiamethoxam were 0.017-0.357 mg kg-1 after application 2-3 times with a preharvest interval (PHI) of 7 days under the designed dosages. The chronic and acute dietary exposure assessment risk quotient (RQ) values of thiamethoxam in Chinese kale for different Chinese consumers were 0.08-0.19% and 0.05-0.12%, respectively, and those of clothianidin were 0.01-0.04% and 0.02-0.04%, respectively, all of the RQ values were lower than 100%. Thiamethoxam in Chinese kale was rapidly degraded following first-order kinetics models. The dietary risk of thiamethoxam and clothianidin through Chinese kale was negligible to consumers. The results from this study are important reference for Chinese governments to developing criteria for the safe and rational use of thiamethoxam, setting maximum residue levels (MRLs), monitoring the quality safety of agricultural products and protecting consumer health. © 2021 Society of Chemical Industry.

ABSTRACTWheat products are consumed worldwide and every day; therefore, herbicides misuse in the wheat ecosystem has become a global food safety issue. Here, a simple and versatile method, QuEChERS (quick, easy, cheap, effective, rugged, and safe) with liquid chromatography-tandem mass spectrometry was developed to measure four herbicides in soil, wheat, and wheat straw – florasulam, carfentrazone-ethyl, fluroxypyr-meptyl, and fluroxypyr. By adjusting the amount of graphitized carbon black from 0 to 10 mg, the herbicides could be extracted with satisfactory recoveries of 80%–110%. Application of two water-dispersible granules showed first-order kinetics as well as half-lives between 1.2 and 5.1 d under open-field conditions. The dissipation kinetics of the four herbicides differed in the soil, wheat, and wheat straw, with residual concentrations in straw at 2 h after application being higher than in soil and faster degradation occurring in straw. The terminal residues in soil, wheat grain, and wheat straw were all below the maximum residue limits. The developed method was easy to handle and versatile; thus, it will facilitate regulation and inspection for possible misuse against Good Agriculture Practices. Moreover, the results of this study will contribute to global environmental protection as well as food safety issues.

Citrus is one of the most important fruit crops worldwide. Fluazinam is a fungicide that is used to control fungal diseases, and its dissipation and residue in citrus fruits should be studied. A Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) procedure combined with gas chromatography with an electron capture detector (GC-ECD) has been developed. The fortified recoveries ranged from 82.1% to 105.9%, with relative standard deviations (RSDs) of less than 5.7%. Fluazinam dissipated relatively quickly following first-order kinetics, with a half-life of 8.5-9.5 days. The experiments on the terminal residue of fluazinam in citrus were conducted at six locations in China, and the risk quotient (RQ) method was applied to citrus fruits for dietary exposure risk assessment based on the terminal residue test. The RQs of fluazinam at three preharvest intervals (PHIs) (21, 28, and 35 days) were all less than 100%, which is an acceptable level for human consumption. The present study provides a reference for the establishment of maximum residue limit (MRL) for fluazinam in citrus. The dissipation and residues of fluazinam in citrus were monitored. The half-life of less than 10 days showed that fluazinam could degrade relatively easily in citrus. The risk assessment also indicated the intake safety of fluazinam in citrus. © 2019 Society of Chemical Industry.

Rosa roxburghii (R. roxburghii) is edible and medicinal fruit rich in vitamin C. Residues and potentially ecological risks of chlorantraniliprole (CAP) in the R. roxburghii orchard have aroused concern considering its extensive use for controlling oriental fruit moth, aphid, and whitefly of R. roxburghii. In this study, an effective UPLC–MS/MS method was developed for quantitation of CAP in R. roxburghii and soil using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) dispersive solid-phase extraction with average recoveries of 73.89–96.63% and a relative standard deviation of &lt;15%. Dissipation dynamics and terminal residue trials under the field conditions in 2021 and 2022 showed that half-lives of CAP in R. roxburghii (2.64–2.70 days) were shorter than those in soil (3.58–3.80 days), and its terminal residues in R. roxburghii and soil were 0.034–0.818 mg kg-1 and 0.003–0.015 mg kg-1, respectively. Long-term dietary and soil ecological risk assessments indicated that the risk quotient was significantly less than 100%, meaning that the use of CAP on R. roxburghii at the recommended dosage was safe to consumers and soil ecology system, and that maximum residue limits (MRLs) and safe pre-harvest intervals of CAP in R. roxburghii were recommended as 0.7 mg kg-1 and 14 days, respectively. Removal experiments of CAP residues from R. roxburghii using simple household processing approaches exhibit that 2% baking soda water had the highest removal efficiency (56.04–60.33%). This study provides the basic data for establishing MRL, the safe and rational use of CAP in R. roxburghii production as well as the household decontamination prior to consumption of R. roxburghii fruits.

The study was conducted to analyze organophosphorus pesticide residues in two common vegetables (cauliflower and eggplant) collected from five local markets of Mymensingh district of Bangladesh. The collected samples were carried to the Pesticide Analytical Laboratory, Entomology Division of Bangladesh Agricultural Research Institute (BARI), Gazipur on the same sampling day. The collected samples were analyzed using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction technique and Gas Chromatography (GC) coupled with Flame Thermionic Detector (FTD). In total, 60 vegetable samples were analyzed in this study. Out of 30 analyzed samples of cauliflower, 5 samples (17% of the total number of samples) contained residues of dimethoate, chlorpyrifos and quinalphos, where 3 samples contained residues above the maximum residue limits (MRLs). Among the 30 analyzed samples of eggplant, 5 samples (17% of the total number of samples) contained residues of chlorpyrifos, quinalphos, and dimethoate, where only one sample contained residues above MRL. This study reflects the actual scenario of pesticide residues remain in cauliflower and eggplant collected from local markets of Mymensingh district, which will help the consumer to be aware of their health and safety. Thus, continuous monitoring of pesticide residues in vegetables should be strengthened. Asian Australas. J. Food Saf. Secur. 2022, 6 (1), 10-17

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established to investigate the residues of emamectin benzoate (EB), imidacloprid (IMI) and five IMI metabolites (IMI-olefin, IMI-urea, IMI-guanidine, 5-OH and 6-CNA) in cabbage. The average recoveries of the seven compounds in cabbage were 80%-102%, with relative standard deviations (RSDs) <8.0%. The limit of quantification (LOQ) for each compound was 0.01 mg kg -1 . Standardized residue tests were carried out in 12 areas of China under Good Agricultural Practice (GAP) conditions. A 10% EB-IMI microcapsule suspension was applied once with the high recommended dosage (18 g a.i. ha-1 ) on cabbage. The residues of EB (<0.01 mg kg-1 ), IMI (<0.016 mg kg-1 ) and the sum of IMI and its metabolites (<0.068 mg kg-1 ) in cabbage on the recommended preharvest interval (PHI) (7 d) were lower than the maximum residue limits (MRLs) in China. Based on residual data from fields, toxicology data, and Chinese dietary patterns, dietary risk assessments were conducted. Both the chronic risk quotients (25.2%-73.1%) and acute risk quotients (0.43%-1.57%) of EB and IMI were below 100%, indicating no unacceptable public health risk for different populations. This study provides guidance on the rational application of these insecticides in cabbage.

To evaluate the residual levels of bifenthrin and dinotefuran, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) and high-performance liquid chromatography-tandem mass spectrometry method for simultaneous detection of bifenthrin and dinotefuran and its major metabolites in wheat was developed and validated. Dietary risk assessments were further performed based on the relevant residual data from 12 wheat fields, toxicology data and dietary patterns. In wheat grain and straw, the recoveries of all analytes ranged from 77 to 102% with the relative standard deviation <9.7% and the limit of quantitation 0.05 mg kg-1 . The highest terminal residue of bifenthrin in wheat grain was 0.069 mg kg-1 and dinotefuran was 0.34 mg kg-1 . Residual concentrations of bifenthrin and dinotefuran decreased to <0.05 and 0.15 mg kg-1 at 21 days (pre-harvest interval), respectively. The chronic risk quotient ranged from 6.4 to 62.7% and the acute risk quotient varied from 0.38 to 17.73%. The chronic and acute dietary risks caused by the terminal residues of the two insecticides were negligible for Chinese populations. The recommended pre-harvest interval was proposed to ensure safe wheat consumption. These data could provide a scientific reference to establish the Chinese maximum residue limit of dinotefuran in wheat.

Registration of a new formulation called 30% suspension concentrate (30% SC, pyriproxyfen 10% + dinotefuran 20%) to inhibit the occurrence of whitefly in tomato is currently under review in China, so it is necessary to research the residue behavior and dietary risk of pyriproxyfen and dinotefuran in tomato under field conditions. According to Good Agricultural Practices (GAP), the formulation was sprayed once at the dosage of 112.5g a.i./ha (active ingredient/hectare) at the initial stage of the occurrence of tomato whitefly and the recommended pre-harvest interval (PHI) for sampling was 5days. Meanwhile, the residues of pyriproxyfen, dinotefuran, and the metabolites of dinotefuran in tomato samples were determined using QuEChERS (quick, easy, cheap, effective, rugged, and safe) and high-performance liquid chromatography-tandem mass spectrometry. The results showed that the terminal residue levels of the analytes detected in tomato samples were below 0.19mg/kg for pyriproxyfen and 0.25mg/kg for dinotefuran at the recommended PHI (5days), which were lower than the maximum residue limits of China. The dietary risk assessment was also carried out based on field trial results, toxicological data, and Chinese dietary pattern. Both the chronic risk quotients (≤ 26.59%) and acute risk quotients (≤ 1.14%, general population, > 1year) of pyriproxyfen and dinotefuran were far below 100%, indicating a low risk to consumers' health. The paper will be conducive to provide guidance for the rational application of these insecticides on tomato.