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1.
在北京和安徽两地开展了田间试验,研究二甲戊灵在土壤与马铃薯植株中的残留降解动态与残留水平。试验样品中的二甲戊灵用乙腈提取,分散固相萃取净化,采用GCMS法,选择离子模式监测(SIM)定量测定。二甲戊灵在马铃薯块茎、植株和土壤的添加回收率分别为84.5%~89.8%、91.5%~101%和78.7%~88.1%,相对标准偏差分别为4.8%~8.5%、6.2%~8.2%和5.2%~7.8%。结果表明,二甲戊灵在马铃薯植株与土壤中的降解动态符合一级动力学模型,在安徽(潮土)和北京(褐土)两地土壤中的半衰期分别为21.0和30.1d,在马铃薯植株中的半衰期分别为9.5和10.6d。收获后,马铃薯块茎中二甲戊灵的残留量小于0.01mg·kg~(-1),低于欧盟规定的二甲戊灵在马铃薯中最大允许残留限量0.05mg·kg~(-1)。研究结果为了解二甲戊灵在环境中的残留水平及食物链迁移转化提供了参考。  相似文献   

2.
在北京市昌平区冬小麦田采用模拟降雨的方法,对不同坡位（坡中和坡底）的土壤进行分层（0~5、5~10、10~15 cm）取样测定,研究了草木樨和狼尾草两种等高草篱在不同雨强（15、20 mm·h-1）和坡度（15%和20%）条件下对土壤苯磺隆残留迁移及分布特征的影响。结果表明,前期干旱条件下,降雨后土壤苯磺隆残留纵向迁移特征明显,无明显的水平移动,亦未产生残留径流输出。草篱能够促进土壤中苯磺隆残留向下迁移,导致草篱带内和无草篱区域土壤中的残留纵向分布特征有较大差异：草篱带内3个土层残留水平相近,而对应坡位无草篱区域残留主要滞留于土壤表层,并随土层加深而显著降低。雨强、草篱、坡度均对土壤苯磺隆残留量有显著影响,草篱的贡献超过雨强和坡度,成为影响坡耕地农药残留纵向迁移行为的首要因素。  相似文献   

3.
通过不同N、P、K施肥量和营养基质与土壤的配比试验,在辣椒冷床育苗上,纯N施用量不得超过0.300 g·㎏-1,速效K不得超过10.000 g·kg~(-1),否则会影响种子的发芽率,速效P的施用量在0.400~9.600 g·kg~(-1),对种子的发芽率影响不大。以纯N 0.300 g·kg~(-1)、有效P 0.040 g·kg~(-1)、速效K 5.000 g·kg~(-1)进行配合施肥,其种子的发芽效果最好。采用辣椒育苗基质与园区土壤按体积比各50%混合作为苗床土和覆盖土,种子的出苗率和成苗率可达90%以上。  相似文献   

4.
采用室内土培和网室盆栽的方法,研究了不同用量的腐植酸对土壤有效硒含量和硒形态以及大蒜硒吸收规律的影响。结果表明:土壤有效硒含量随着腐植酸用量的提高而增加,20%OM处理的土壤有效硒含量(43.3~50.6μg·kg~(-1))10%OM(37.6~48.8μg·kg~(-1))5%OM(36.0~44.1μg·kg~(-1))CK(33.0~41.5μg·kg~(-1))。可溶态硒与土壤有机质含量的关联度最大(关联系数为0.821),其次为有机硫化物结合态硒(关联系数为0.693),铁锰氧化物结合态硒关联度最低(关联系数为0.482)。随着腐植酸用量的增加,土壤有机质含量得到相应提高,土壤中有机质的含量与可溶态硒、可交换态及碳酸盐结合态硒和有机硫化物结合态硒呈显著正相关,其相关系数分别为0.963、0.962和0.906,而与其他形态的硒相关性不明显。大蒜各部位干重的硒含量为根(0.167~0.653 mg·kg~(-1))茎(0.114~0.326 mg·kg~(-1))叶(0.056~0.086 mg·kg~(-1)),且4个处理大蒜鳞茎鲜重的硒含量为0.018~0.110 mg·kg~(-1),均达到了富硒食品标准(HB001/T—2013)。  相似文献   

5.
在建立液相色谱三重串联四极杆质谱（LC-MS/MS）检测技术的基础上,采用PVC材料的圆柱形盆钵栽培方法,研究了不同土壤环境条件下甲磺隆和氯磺隆的残留特性。结果表明,甲磺隆和氯磺隆在水稻根际和非根际土壤中的残留量均呈不断下降趋势。处理后15d,根际和非根际土壤中两种农药残留量分别下降了44.7%和41.5%（甲磺隆）及38.7%和40.1%（氯磺隆）,根际和非根际的残留差异不显著（P〉0.05）;处理后31d,残留量分别下降了77.7%和64.8%（甲磺隆）及62.7%和50.1%（氯磺隆）,差异达极显著水平（P〈0.01）;处理后63d,残留量分别下降了96.4%和85.1%（甲磺隆）及90.0%和79.4%（氯磺隆）,残留差异达极显著水平（P〈0.01）。甲磺隆的降解趋势和氯磺隆基本一致,但下降幅度比氯磺隆大。二者在水稻根际和非根际土壤中的残留量均符合一级动力学方程式C=C0e-λ（tC代表浓度;C0代表初始浓度;t时间）,决定系数范围在0.9342～0.9957之间。在种植水稻的条件下,下层土的农药残留量呈先上升后下降的趋势,处理后数日内达最高点,之后不断下降,122d后低于检测限。水稻下层土残留的从无到有说明农药在土壤中的淋溶可能是水田环境农药残留降解的原因之一。干旱土壤条件下,土壤的淋溶作用不明显。说明水旱轮作有利于农药残留在土壤环境中的降解。  相似文献   

6.
建立了气相色谱结合Qu ECh ERS-悬浮固化分散液液微萃取(DLLME-SFO)测定苹果、柑橘中7种有机磷类农药残留的检测方法。待测样品用Qu ECh ERS方法萃取净化后,再用DLLME-SFO方法进行浓缩,最后用气相色谱(FPD)进行检测。实验考察了萃取剂种类与体积,分散剂种类与体积以及盐浓度对萃取效果的影响。DLLME-SFO前处理过程中,将含待测物的乙腈1 m L提取液作为分散剂,50μL十二醇作为萃取剂,加入到氯化钠盐溶液中进行萃取浓缩。结果表明,在苹果和柑橘两种基质中7种有机磷农药在5、10、25μg/kg 3个添加水平下农药的平均回收率为76.34%~107.41%,相对标准偏差(RSD)为0.47%~6.70%,方法的定量限(LOQ)为0.13μg/kg~1.67μg/kg。该方法简单、灵敏高、重复性好,可用于苹果、柑橘中有机磷农药的检测。  相似文献   

7.
为建立葡萄酒中苯醚甲环唑的测定方法,以超声辅助-凝固-漂浮分散液液微萃取(UADLLME-SFO)为富集、净化手段,采用气相色谱-质谱(GC-MS)联用法检测葡萄酒中苯醚甲环唑的残留量,应用正交试验对萃取参数进行优化。结果表明,最适宜的萃取条件为:萃取剂十一醇30μL、超声时间5 min、氯化钠浓度30 g·L~(-1),此条件下苯醚甲环唑的检出限为2.3 ng·L~(-1),相对标准偏差(n=5)在3.5%~6.2%之间,当添加浓度为1μg·L~(-1)和50μg·L~(-1)时,苯醚甲环唑的添加回收率在90.2%~98.4%之间。本研究结果为葡萄酒中苯醚甲环唑残留的检测提供了研究方法和科学依据。  相似文献   

8.
建立以多壁碳纳米管(MWCNTs)为吸附剂,分散固相萃取结合超高效液相色谱-串联质谱法(DSPE-UPLC-MS/MS)同时测定鸡蛋中4种抗流感病毒药物金刚烷胺、金刚乙胺、美金刚、奥司他韦的残留。样品经1%乙酸乙腈/水(9/1,v/v)提取,MWCNTs分散净化,以0.1%甲酸水和甲醇为流动相,经Agilent SB-Aq色谱柱分离,采用正离子多反应监测模式,内标法定量。结果表明,在优化的流动相梯度条件下,具有同分异构的金刚乙胺和美金刚可有效分离;4种药物在0.1~10μg/L范围内线性关系良好,相关系数均大于0.992 9。在0.5~5μg/kg浓度范围内的3个添加水平,4种药物在鸡蛋中的回收率在92.2%~106.7%之间,相对标准偏差为1.1%~6.3%,定量限为0.5μg/kg。结果说明该方法具有良好的准确度、精密度和灵敏度,适用于鸡蛋样品中4种抗流感病毒药物残留的测定。  相似文献   

9.
建立了呋虫胺在糙米、稻壳、水稻植株、土壤和稻田水中残留的分散固相萃取—高效液相色谱-串联质谱(DSPE-HPLC-MS/MS)分析方法 ,并采用该方法研究了呋虫胺在水稻植株、土壤、田水中的消解动态规律和糙米、稻壳、植株、土壤中最终残留水平。各基质经乙腈提取,N-丙基乙二胺(PSA)净化后,经Waters X-Bridge HILIC色谱柱分离,电喷雾电离串联质谱正离子多重反应监测(MRM)模式测定,基质匹配标准曲线外标法定量。在0.1~0.8 mg/kg的添加水平下,呋虫胺在5种基质中的回收率为68.5%~114.5%,相对标准偏差(RSD)为2.7%~10.8%,最低检测浓度(LOQ)在0.1~0.2 mg/kg。2013-2014年,在黑龙江、北京和浙江两年3地的田间残留试验表明,呋虫胺在水稻植株、土壤和田水中的降解速度较快,在植株中的消解半衰期为1.75 d;采用20%呋虫胺水分散粒剂,分别按照推荐剂量(120 g a.i/ha)和推荐剂量的1.5倍(180 ga.i/ha)施药2~3次,距末次施药7d、14d、21d时,呋虫胺在糙米中的最大残留量均小于0.1 mg/kg,远低于我国规定的最大允许残留限量(MRL)值(1 mg/kg)。  相似文献   

10.
《土壤通报》2017,(6):1493-1498
通过水稻盆栽实验,研究了不同添加量的组配改良剂谷壳生物炭和石灰石(TS)对Cd污染土壤的修复效果及水稻对Cd吸收累积的影响。结果表明:(1)添加TS(2~4 g kg~(-1))能显著提高土壤pH值,与对照相比,Cd含量为0.5 mg kg~(-1)和5.0 mg kg~(-1)土壤pH值分别增加了0.69~1.38和0.70~1.12个单位;(2)TS能显著降低土壤中Cd的生物有效性,在Cd含量为0.5 mg kg~(-1)和5.0 mg kg~(-1)土壤中,添加量为2~4 g kg~(-1)时,能使Cd的Ca Cl2提取态含量分别降低13.3%~86.7%和12.2%~73.6%,使Cd的TCLP提取态含量分别降低52.9%~76.5%和37.1%~76.8%;(3)添加TS(2~4 g kg~(-1))能显著降低水稻根系、秸秆、糙米对Cd的吸收累积,在2种不同Cd含量的土壤中(0.5 mg kg~(-1)和5.0 mg kg~(-1)),使糙米Cd含量分别降低了40.8%~60.0%和49.9%~86.6%,糙米Cd含量低于国家食品卫生标准0.2 mg kg~(-1)的限制。  相似文献   

11.
A prototype multiresidue method based on fast extraction and dilution of samples followed by flow injection mass spectrometric analysis is proposed here for high-throughput chemical screening in complex matrices. The method was tested for sulfonylurea herbicides (triflusulfuron methyl, azimsulfuron, chlorimuron ethyl, sulfometuron methyl, chlorsulfuron, and flupyrsulfuron methyl), carbamate insecticides (oxamyl and methomyl), pyrimidine carboxylic acid herbicides (aminocyclopyrachlor and aminocyclopyrachlor methyl), and anthranilic diamide insecticides (chlorantraniliprole and cyantraniliprole). Lemon and pecan were used as representative high-water and low-water content matrices, respectively, and a sample extraction procedure was designed for each commodity type. Matrix-matched external standards were used for calibration, yielding linear responses with correlation coefficients (r) consistently >0.99. The limits of detection (LOD) were estimated to be between 0.01 and 0.03 mg/kg for all analytes, allowing execution of recovery tests with samples fortified at ≥0.05 mg/kg. Average analyte recoveries obtained during method validation for lemon and pecan ranged from 75 to 118% with standard deviations between 3 and 21%. Representative food processed fractions were also tested, that is, soybean oil and corn meal, yielding individual analyte average recoveries ranging from 62 to 114% with standard deviations between 4 and 18%. An intralaboratory blind test was also performed; the method excelled with 0 false positives and 0 false negatives in 240 residue measurements (20 samples × 12 analytes). The daily throughput of the fast extraction and dilution (FED) procedure is estimated at 72 samples/chemist, whereas the flow injection mass spectrometry (FI-MS) throughput could be as high as 4.3 sample injections/min, making very efficient use of mass spectrometers with negligible instrumental analysis time compared to the sample homogenization, preparation, and data processing steps.  相似文献   

12.
A sensitive and reliable method was developed and validated for trace determination of sulfonylurea herbicides residues in cereals (wheat, rice, and corn) by liquid chromatography-tandem mass spectrometry. The selected analytes were ethoxysulfuron, ethametsulfuron-methyl, bensulfuron-methyl, chlorimuron-ethyl, pyrazosulfuron-ethyl, and cyclosulfamuron. In this work, the extraction procedure was performed by using a mixture solvent of phosphate buffer (pH 9.5)/acetonitrile (8:2, v/v) as the extraction solvent and then was cleaned up by using Spe-ed C18/18% SPE cartridges, providing good recoveries for all of the tested analytes and with no matrix effects affecting method accuracy. The limits of detection for the studied analytes in cereal samples were between 0.043 and 0.23 μg kg(-1), and the limits of quantification were between 0.14 and 0.77 μg kg(-1), lower in all cases than the maximum residue limits permitted by the European Union for this kind of food. The developed methodology has demonstrated its suitability for the monitoring of these residues in cereal samples with high sensitivity, precision, and satisfactory recoveries.  相似文献   

13.
The behavior of four sulfonylurea herbicides (metsulfuron methyl, chlorsulfuron, chlorimuron ethyl, and bensulfuron methyl) was studied in the presence of various hydroxy compounds. When dissolved at 30 degrees C in simple primary, secondary, or tertiary alcohols (methanol, ethanol, isopropyl alcohol, and tert-butyl alcohol) and in glycerol or in poly(ethylene glycol), most of these herbicides underwent rapid alcoholysis involving the breakdown of the urea part of the molecule. The corresponding sulfonyl carbamate is recovered in high yields, along with a small amount of sulfonylamide formed in the concomitant hydrolysis. Degradation rate constants and the selectivity of conversion were established. The addition of buffered water (pH 7.0) inhibited the alcoholysis reaction, leaving only hydrolysis, as already observed with concentrated saccharide solutions. In phenol solution, slight herbicide hydrolysis was primarily observed. It appeared that alcoholysis reactions only occurred under very particular conditions when sulfonylurea herbicides are dissolved in pure alcohols, without buffered water. These results led to the conclusion that in soil, similar alcoholysis reactions seem unlikely.  相似文献   

14.
Total phenolic and tocopherol contents and free radical scavenging capability of wheat bran extracted using conventional and microwave-assisted solvent extraction methods were studied. Three different solvents (methanol, acetone, and hexane) were used in the conventional solvent extraction. Methanol was the most effective solvent, producing higher extraction yield (4.86%), total phenolic compound content (241.3 μg of catechin equivalent/g of wheat bran), and free radical scavenging capability (0.042 μmol of trolox equivalent/g of wheat bran) than either acetone or hexane. However, there was no significant difference in the total tocopherol contents (13.6–14.8 μg/g of wheat bran) among the three different solvent extraction methods. Microwave-assisted solvent extraction using methanol significantly increased the total phenolic compound content to 467.5 and 489.5 μg of catechin equivalent; total tocopherol content to 18.7 and 19.5 μg; and free radical scavenging capability to 0.064 and 0.072 μmol of trolox equivalent/g of wheat bran at extraction temperatures of 100 and 120°C, respectively. However, extraction yields of conventional methanol solvent and microwave-assisted methanol extractions at different temperatures were not significantly different.  相似文献   

15.
Pyrazosulfuron ethyl (PE) and halosulfuron methyl (HM) are two new highly active sulfonylurea herbicides that have been widely used for weed control in a variety of vegetables and other crops. These two herbicides have similar molecular structures, differing only in the substitutions on the pyrazole ring. Chemical hydrolysis is a primary process affecting the environmental fate of sulfonylurea pesticides. The hydrolytic transformation kinetics of PE and HM were investigated as a function of pH and temperature. For both herbicides, the hydrolysis rate was pH-dependent and increased with increasing temperature. The hydrolysis of both sulfonylureas was much faster in acidic or basic media than under neutral conditions. Identification of hydrolytic products by liquid chromatography-mass spectrometry (LC-MS) suggested that both PE and HM were subject to cleavage and contraction of the sulfonylurea bridge. The hydrolysis rate of HM was significantly higher than that of PE in alkaline solutions, despite their structural similarity. A chlorine substitution on HM's pyrazole ring makes HM more susceptible to bridge contraction than PE under basic conditions. The hydrolysis of HM and PE was relatively unaffected by the presence of cyclic oligosaccharides (cyclodextrins), indicating that natural OH-containing organic compounds occurring in aquatic environments may have little impact on the transformation of these sulfonylurea herbicides.  相似文献   

16.
A new rapid and sensitive method based on matrix solid-phase dispersion (MSPD) followed by liquid chromatography-electrospray-tandem mass spectrometry was devised for the determination of biogenic amines at trace levels in cheese samples. The method required 0.25 g of sample, CN-bonded silica as a dispersant sorbent, and a formic acid aqueous solution/methanol mixture as an eluting solvent. Extraction recoveries from soft cheese products were calculated in the 98 +/- 4-110 +/- 6% range. A procedure based on solid-phase extraction was also evaluated for the extraction of these compounds in cheese. Chromatographic separation was performed using a C18 column with an aqueous ammonium acetate/methanol mixture as the mobile phase under gradient conditions. The method was validated in terms of detection limits (LOD), quantitation limits (LOQ), linearity, recovery, precision, and trueness. Results in the 0.05-0.25 mg kg(-1) range were obtained for the LOD of histamine, tyramine, and beta-phenylethylamine in soft cheese samples. Linearity was established over 2 orders of magnitude. Excellent precision in terms of intra-day repeatability was calculated (RSD% < 5). The applicability of the method to the determination of biogenic amines in cheese products was demonstrated.  相似文献   

17.
We developed and validated three different sample preparation and extraction methods followed by HPLC-MS/MS (negative electrospray ionization) analysis for the quantification of estrogenic isoflavones (formononetin, daidzein, equol, biochanin A, and genistein) and coumestrol in red clover, soil, and manure. Plant and manure samples were solid-liquid extracted, whereas soil was extracted with accelerated solvent extraction. Absolute recoveries were between 80 and 93%, 20 and 30%, and 14 and 91% for plant, soil, and manure samples, respectively. Relative recoveries ranged from 75 to 105% for all matrices, indicating that isotope-labeled internal standards (13C?-formononetin, 13C?-daidzein, 13C?-equol, 13C?-biochanin A, and 13C?-genistein) were capable to compensate for losses during analysis. The limits of detection in red clover, soil, and manure were 3-9 μg/g(dryweight(dw)), 0.6-8.2 ng/g(dw), and 34.2 ng/g(dw) to 17.0 μg/g(dw), respectively. Formononetin was the most dominant compound in red clover plants (up to 12.5 mg/g(dw)) and soil (up to 3.3 μg/g(dw)), whereas equol prevailed in manure (up to 387 μg/g(dw)).  相似文献   

18.
The efficiency of filter strips in protecting watercourses against herbicides in run‐off was evaluated in field experiments in western Germany. Surface run‐off caused by natural rainfall and related transport of metolachlor, terbuthylazine and pendimethalin were measured on plots of 40 m length without filter strips (F0), and after passing over three types of herbicide‐untreated field margin: 12 m conservation headland (CH12), 6 m (GF6) and 12 m grass strips (GF12). Run‐off was also measured after simulated rainfall on 7 m long plots without (F0) and with 3 m grass strips (GF3). All three herbicides were transported both in dissolved and in adsorbed forms; the partitioning depended on their water solubility with metolachlor and terbuthylazine mainly translocated in dissolved form (F0: highest mean concentrations for a natural run‐off event 721 and 220 μg L?1, respectively). Pendimethalin was predominantly transported in adsorbed form (maximum mean concentration 11.2 μg L?1). In the sediment, the highest mean herbicide contents in a single natural event (F0) accounted for 2294 μg kg?1 (metolachlor), 1317 μg kg?1 (terbuthylazine) and 5648 μg kg?1 (pendimethalin). The proportions of applied herbicide translocated were 0.3% (metolachlor), 0.2% (terbuthylazine) and 0.06% (pendimethalin; F0, natural rainfall). The extent of herbicide transport decreased with time but within this trend soil sealing, soil moisture and amount and intensity of rainfall increased losses. Compared with the F0 plots, the reduction of herbicide translocation after natural rainfall reached 80–83% (CH12), 80–88% (GF6) and >99% (GF12) over the 3‐year period. The 12 m grass strips allowed only one extreme run‐off event to pass through, thus providing a highly effective watercourse protection against herbicide pollution.  相似文献   

19.
An analytical method for the simultaneous determination of residues of eight neonicotinoid insecticides and two metabolites in honey using LC-MS/MS was developed and validated. Two approaches of sample preparation were investigated, with the final method involving acetonitrile extraction and subsequent cleanup by dispersive solid-phase extraction (QuEChERS type). Validation was based on quintuplicate analysis at three fortification levels and showed satisfactory recoveries (60-114%) and high precision (RSDs between 2.7 and 12.8%). Low limits of detection and quantification could be achieved for all analytes ranging from 0.6 to 5 μg/kg and from 2 to 10 μg/kg, respectively. Investigations of Austrian honey samples revealed the presence of acetamiprid, thiacloprid, and thiamethoxam residues in honey; however, no sample exceeded the maximum residue limits. On average, flower honey samples contained neonicotinoid residues in higher quantities compared to forest honey samples.  相似文献   

20.
The application of liquid chromatography time-of-flight mass spectrometry (LC/TOF-MS) for the identification and quantitation of four herbicides (simazine, atrazine, diuron, and terbuthylazine) in olive oil samples is reported here. The method includes a sample treatment step based on a preliminary liquid-liquid extraction followed by matrix solid-phase dispersion (MSPD) using aminopropyl as a sorbent material. A final cleanup step is performed with florisil using acetonitrile as an eluting solvent. The identification by LC/TOF-MS is accomplished with the accurate mass (and the subsequent generated empirical formula) of the protonated molecules [M + H]+, along with the accurate mass of the main fragment ion and the characteristic chlorine isotope cluster present in all of them. Accurate mass measurements are highly useful in this type of complex sample analyses since they allow us to achieve a high degree of specificity, often needed when other interferents are present in the matrix. The mass accuracy typically obtained is routinely better than 2 ppm. The sensitivity, linearity, precision, mass accuracy, and matrix effects are studied as well, illustrating the potential of this technique for routine quantitative analyses of herbicides in olive oil. Limits of detection (LODs) range from 1 to 5 microg/kg, which are far below the required maximum residue level (MRL) of 100 microg/kg for these herbicides in olive oil.  相似文献   

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