QuEChERS-高效液相色谱串联质谱法测定甜橙中哒螨灵和螺螨酯

[目的]建立了甜橙全果、果肉、果皮、果渣、橙汁和精油等6项基质中哒螨灵和螺螨酯的QuEChERS-高效液相色谱-串联质谱分析检测方法(HPLC-MS/MS)。[方法]甜橙样品经乙腈提取,PSA、GCB、MgSO4净化,高效液相色谱-串联质谱仪配备电喷雾正离子多反应监测(MRM),外标法定量。[结果]甜橙6种基质通过此分析检测方法,哒螨灵和螺螨酯在0.001~1.25 mg/L质量浓度范围线性相关系数不小于0.9965,3个加标水平(0.01、0.5、5 mg/kg)下哒螨灵回收率为81%~93%,RSD为0.5%~6.5%,螺螨酯回收率为81%~99%,RSD为0.5%~7.9%。[结论]该方法简单、方便、灵敏度、准确度高,覆盖甜橙全项样品基质,可适用于大批量样品快速分析。     

2021年我国农药相关标准发布概况

收集整理了2021年我国公布的农药相关标准共315项,其中,发布国家标准27项、行业标准40项、地方标准72项、团体标准176项.     

Mobility and distribution of eight fungicides in surface,skin and pulp in grapes. An application to pyraclostrobin and boscalid

The study discusses the mobility and distribution of vinclozolin, dichlofluanid, penconazol, captan, quinoxyfen, fluquinconazol, boscalid and pyraclostrobin residues in surface, skin and pulp in red grapes. A lab test was carried out by immersing grapes in solutions with different concentrations of fungicides and for different periods of time; followed by a determination of the fungicide residues by GC-ECD with an additional confirmation by GC-MS. The distribution between surface, skin and pulp of the grapes was also determined. The percentage sorption ranged from 6.4 to 116%. Results showed that sorption values depended on the time that grapes had been in contact with the fungicide solutions, but not on the initial concentration of solutions. Residues were mainly found in skin, with percentages ranging from 53.0 to 88.4% of total residues. In pulp, these values ranged from 9.6 to 41.7%. Pyraclostrobin showed higher penetration than the other compounds.A field test using three new commercial formulations containing pyraclostrobin, boscalid and a mixture of both, was carried out by applying these formulations to a vineyard. When fungicides were applied individually the ratios of the skin/pulp residues were similar to those obtained in lab; whereas when a mixture of both pesticides was sprayed results showed a lower penetration of the fungicides in the grape pulp.     

Dissipation of four fungicides on greenhouse strawberries and an assessment of their risks

Risk assessments of the fungicides pyraclostrobin, iprodione, tebuconazole and cyprodinil were carried after determining their persistence on strawberries following two applications by spraying in a greenhouse. The Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was used for sample preparation, and high-performance liquid chromatography-tandem mass spectrometry and gas chromatography-tandem mass spectrometry were used for sample analysis. The range for the average recoveries of the four fungicides was 86.2–105.4 %, and the relative standard deviation range was 2.7–6.1 %. The half-lives of pyraclostrobin, iprodione, tebuconazole and cyprodinil after a single application were 3.7, 3.6, 3.3 and 2.8 d, respectively. Compared with a single application, a second application of the fungicides increased the average concentrations of residues left on the strawberries. Risk assessments of the four fungicides were conducted by comparing national estimated daily intakes against acceptable daily intakes under good agricultural practice conditions. With application at the recommended dosage, strawberries sprayed with pyraclostrobin, iprodione and tebuconazole were safe for consumption after two applications. By contrast, while the first application of cyprodinil was safe, the second presented a high health risk. Even at the recommended dosage (720 a. i. g ha-1), repeat applications of cyprodinil should be banned.     

Distribution and degradation kinetics of cyhalodiamide in Chinese rice field environment

Cyhalodiamide is a novel agrochemical which is effective against Lepidoptera pests, including Cnaphalocrocis medinalis, Chilo suppressalis, Pieris rapae, Plutella xylostella, Helicoverpa armigera, etc. In the study, a fast and accurate analytical method was developed to detect cyhalodiamide in Chinese typical rice field environment by a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) method with UPLC-MS/MS (ultra-high performance chromatography-tandem mass spectrometry). The mean recoveries of cyhalodiamide varied from 73.5% to 107.5%, with the RSDs from 1.2% to 10.7%. The limits of determination (LODs) were 0.0005 mg·kg^-1, and the limits of quantitation (LOQs) were from 0.002 to 0.01 mg·kg^-1 in all five matrices. This method was used to determine cyhalodiamide residues for studies of the distribution and degradation kinetics in rice field environment. The field trials results showed that cyhalodiamide was easily degradable and the half-lives were 4.2-13.6 d in rice straw, 8.77 d in paddy soil and 5.37-8.45 d in paddy water, respectively. The final residues of cyhalodiamide in brown rice were below 0.35 mg·kg^-1. The used dosage of 33.75 g·hm^-2 with pre-harvest interval (PHI) of 21 d and the maximum residue limit (MRL) of cyhalodiamide in rice at 0.1 mg·kg^-1 were recommended, which would be safe to human health and environment. The developed analytical method will be useful to monitor cyhalodiamide residues and safety evaluation in rice environment.     

2020年我国登记的新农药

2020年,我国共登记了6个新农药,其中新杀虫剂登记数量最多,占50％;生物源农药占33.3％,说明生物源农药在蓬勃发展;国内登记的新农药占50％,体现了我国农药制造和研发水平在提高.6个新农药都属低毒或微毒,剂型均对环境友好.新农药的增加,将扩大低风险的农药数量,逐步优化我国的农药品种结构.     

超高效液相色谱-串联质谱法测定杨梅中噻嗪酮残留量

[目的]建立超高效液相色谱-串联质谱法测定杨梅中噻嗪酮残留量的方法。[方法]杨梅样品经乙腈提取,弗罗里硅土柱净化,超高效液相色谱-串联质谱检测。[结果]噻嗪酮在0.5~500μg/L范围内线性关系良好,相关系数为0.9952,在0.01~2.0 mg/kg添加水平下,噻嗪酮在杨梅中的平均回收率为88%~92%,相对标准偏差为2.43%~3.88%,噻嗪酮在杨梅中的定量下限为0.01 mg/kg。[结论]该方法简便、快速、准确、灵敏度高,可用于杨梅中噻嗪酮的残留检测。     

吡噻菌胺及其代谢物在柑橘中的残留行为及膳食风险评估

目的 建立基于超高效液相色谱-串联质谱的柑橘中吡噻菌胺及其代谢物1-甲基-3-（三氟甲基）-1H-吡唑-4-甲酰胺(1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxamide, PAM)残留分析方法,并开展残留实验,以研究吡噻菌胺及其代谢物在柑橘中的残留行为及膳食风险评估。方法 样品中残留的吡噻菌胺及PAM采用乙腈提取后,经N-丙基乙二胺和无水硫酸镁净化,超高效液相色谱-串联质谱仪检测,基质匹配外标法定量。结果 在0.0005~0.0500 mg/L范围内呈线性关系,相关系数均大于0.999;添加浓度为0.010~1.000 mg/kg时,吡噻菌胺及代谢物在柑橘中平均回收率范围分别为87%~101%和85%~106%,最大相对标准偏差为6.5%,方法定量限(limits of quantification, LOQs)均为0.010 mg/kg;以推荐剂量施药,吡噻菌胺总残留量在柑橘全果中半衰期为18.2 d;末次施药后间隔21 d采集的全果、果肉、果皮中吡噻菌胺总残留量平均值分别为0.277、0.091和0.473 mg/kg。膳食风险评估表明,吡噻菌胺在不同人群中的膳食风险概率均远小于100%。结论 该方法简便、准确、灵敏度高,可用于柑橘中吡噻菌胺及其代谢物的残留检测。最终残留量实验显示,全果、果肉、果皮中吡噻菌胺总残留量均未超过已制定的最大残留限量,对不同人群产生的膳食风险可接受。     

Pesticide residues in some Egyptian spices and medicinal plants as affected by processing

Pesticide residues were determined in Egyptian spices and medicinal plants. For this purpose, a total of 303 samples, which represent 20 different plants were collected from sources in Egypt and several shipments All the collected samples were analyzed for the determination of organophosphorus and organochlorine residues. The obtained results showed the predominance of malathion in most of the analyzed samples. The detected concentrations of it in jews mallow, dill, celery, tea, caraway, chamomile and saffron exceeded the maximum permissible levels (MPLs), as did the concentrations of dimethoate in caraway and chamomile samples. Low levels of profenofos, pirmiphos-methyl, chloropyrifos. parathion and diazinon were determined in the analyzed samples. Residues of lindane, aldrin, dieldrin, DDT, chlordane and endrin in chamomile samples exceeded the MPLs. Residues of aldrin and dieldrin in karkade were higher than the MPLs, as was chlordane in peppermint. Residues were not detected in the watery extract when the medicinal plant was boiled in water. Also, immersing the plants in hot water transferred some pesticide residues to the aqueous extract.