Systemic effects of thiamethoxam and chlorantraniliprole seed treatments on adult Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) in rice

BACKGROUND: Feeding assays using adult rice water weevils and foliage of plants treated as seeds with chlorantraniliprole and thiamethoxam at different rates were conducted to evaluate the systemic adulticidal and feeding effects. Dose–mortality relationships were determined for thiamethoxam seed treatments by combining leaf area lost due to feeding and insecticide residues analyzed by LC/MS/MS. Changes in adulticidal activity of thiamethoxam were also investigated by contrasting adult mortalities at the 5–6‐leaf and tillering stages of rice. RESULTS: Adult weevil mortalities and leaf consumption rates on foliage were affected in thiamethoxam but not in chlorantraniliprole treatments when rice was at the 6–7‐leaf stage. The LD₅₀ for weevils feeding on thiamethoxam‐treated rice at the 2–3‐leaf stage was 447 pg insecticide weevil^?1 (95% CL: 25–830 pg weevil^?1) but was lower (142 pg weevil^?1; 95% CL: 102–180 pg weevil^?1) in experiments with 3–4‐leaf‐stage plants. Mortalities on leaves from 5–6‐leaf‐stage plants were consistently higher than on leaves from tillering plants. Thiamethoxam residues measured by ELISA increased with seed treatment rate and differed between plant stages. CONCLUSION: The LD₅₀ values developed in this study are the first values for leaf‐feeding insects on foliage of plants treated as seeds with thiamethoxam. The attrition of adulticidal activity of thiamethoxam in foliage of older plants may help to explain the reduced effectiveness of seed treatments against rice water larvae that is seen at later stages of rice growth in field studies. The differential activity of these two seed treatments on adults suggests that adult mortality contributes to the field efficacy of thiamethoxam but not to that of chlorantraniliprole. Copyright © 2012 Society of Chemical Industry     

吡嘧磺隆在水稻中的残留消解及膳食风险评估

本文建立了超高效液相色谱-串联质谱法(UPLC-MS/MS)测定糙米、稻壳、稻田水、土壤和水稻植株中吡嘧磺隆残留的分析方法,并对我国不同人群的膳食暴露风险进行评估。样品经甲酸乙腈提取,超纯水稀释10倍,UPLC-MS/MS检测。结果表明:在添加水平为0.000 5~1mg/kg范围内,吡嘧磺隆在稻田水、土壤、糙米、稻壳和水稻植株中平均回收率为73.7%~113.6%,相对标准偏差(RSD)为1.5%~12.5%。2014年-2015年北京、安徽和广西田间规范残留试验表明,吡嘧磺隆在水稻植株、土壤和稻田水中的消解符合一级动力学方程,半衰期分别为0.8~2.9d,4.4~5.2d和0.9~5.9d。膳食摄入风险评估显示:我国各类人群的吡嘧磺隆国家估计每日摄入量(NEDI)为0.002 2~0.005 3μg/kg,风险商值(RQ)为5.1×10~(-5)~1.23×10~(-4),表明吡嘧磺隆在糙米中的残留水平不会对人类健康造成不可接受的慢性中毒风险。     

超高效液相色谱-串联质谱法分析氟虫双酰胺在稻田生态系统中的消解动态

应用超高效液相色谱-串联质谱(UPLC-MS/MS)建立了氟虫双酰胺(NNI-0001)及其代谢产物(NNI-des)在土壤和田水中的残留检测方法。样品采用乙腈提取,乙二胺-N-丙基硅烷吸附剂(PSA)净化,UPLC-MS/MS检测。氟虫双酰胺及其代谢产物NNI-des在土壤和田水中的最低检测浓度分别为0.002 mg/kg和0.001 mg/L,最小检出量分别为1.2×10-13和3.1×10-14 g。在土壤和田水中的添加水平为0.001~1 mg/kg(mg/L)条件下,氟虫双酰胺及其代谢产物NNI-des的平均回收率在78.2%~108.2%之间,相对标准偏差在8.2%~15.3%之间。消解动态试验结果表明,氟虫双酰胺在土壤和田水中的半衰期分别为1.0和 5.4 d。施药21 d后,消解率均在85%以上,属易降解农药。     

超高效液相色谱-串联质谱法检测水稻及稻田环境中速灭威的残留

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)检测稻田土壤、田水、水稻植株、谷壳和糙米样品中速灭威残留的分析方法。样品经乙腈提取及盐析处理后,用乙二胺-N-丙基(PSA)和白炭黑(SiO2·nH2O)净化,UPLC-MS/MS 多离子反应监测模式下测定。结果表明,在0.005~1 mg/L 范围内,速灭威的仪器响应值与进样质量浓度间呈良好线性关系,相关系数(r)大于0.98。当添加水平为0.01~5 mg/kg(田水样品中为0.005~1 mg/L)时,速灭威在不同样品基质中的平均回收率为76.7% ~107.8%,相对标准偏差(RSD)为1.7% ~8.5%,最小检出量(LOD)均为2.0×10-13g,最低检测浓度(LOQ) 除在田水样品中为0.005 mg/L外,其余均为0.01 mg/kg。当按推荐剂量的1.5倍(有效成分45 g/hm2)分别施药2次和3次后,采用所建方法测得距最后一次施药10、14和21 d采收的糙米样品中速灭威的最终残留量均为未检出(低于0.01 mg/kg)。     

Photolytic versus microbial degradation of clomazone in a flooded California rice field soil

BACKGROUND: Clomazone is a popular herbicide used on California rice fields and exhibits rapid anaerobic microbial degradation (t_1/2 = 7.9 days). To test the potential of direct and indirect photolytic degradation as a cofactor in the overall degradation rate, sacrificial time‐series microcosms were amended with water, non‐sterilized soil + water and sterilized soil + water. Clomazone was added to each microcosm, which was then exposed to natural and artificial sunlight over 35 days. Water and acetonitrile extracts were analyzed for clomazone and metabolites via LC/MS/MS. RESULTS: The calculated pseudo‐first‐order degradation rate constants (k) were k_water = 0–0.005 ± 0.003 day^?1, k_sterile = 0–0.005 ± 0.003 day^?1 and k_non?sterile = 0.010 ± 0.002–0.044 ± 0.007 day^?1, depending on light type. The formation of ring‐open clomazone, a microbial metabolite, correlated with clomazone degradation. Trace amounts of 5‐hydroxyclomazone (m/z = 256 → 125), aromatic hydroxyclomazone (m/z = 256 → 141) and an unknown product (m/z = 268 → 125) were observed. CONCLUSIONS: The photolytic degradation rate depends on both light type and the quality of the chromophores that induce indirect photolysis. Microbial degradation was found to be sensitive to temperature fluctuations. Overall, microbes are shown to be more detrimental to the environmental fate of clomazone than photolysis. Copyright © 2012 Society of Chemical Industry     

QuEChERS-超高效液相色谱-串联质谱法同时测定大米、小麦和动物源食品中异丙隆及其代谢物脱甲基异丙隆残留

本研究建立了超高效液相色谱-串联质谱法(UHPLC-MS/MS)同时测定异丙隆及其代谢物脱甲基异丙隆在大米、小麦、牛肉、牛奶、鸡肉和鸡蛋的残留检测方法。样品经2%甲酸乙腈提取,以N-丙基乙二胺(PSA)净化,利用乙腈和0.2%甲酸水作为流动相梯度洗脱,T3色谱柱分离,在多反应监测模式下定量分析,基质外标法定量。结果表明:异丙隆及其代谢物脱甲基异丙隆溶剂标准曲线和基质标准曲线在1~1 000μg/L范围内线性关系良好,相关系数均大于0.99。在4个加标水平下,异丙隆日内平均回收率为74.0%~107.0%,相对标准偏差0.7%~12.9%;日间平均回收率为76.2%~108.7%,相对标准偏差1.1%~19.8%。脱甲基异丙隆日内平均回收率为76.9%~113.5%,相对标准偏差0.6%~13.9%;日间平均回收率为77.7%~107.4%,相对标准偏差2.2%~17.4%。异丙隆和脱甲基异丙隆的定量限均为1.0μg/kg。该方法简便、快捷、准确、灵敏度高,适用于异丙隆和脱甲基异丙隆在大米、小麦、牛肉、牛奶、鸡肉和鸡蛋6种基质中残留的检测,为解决异丙隆和脱甲基异丙隆在食品中残留的安全问题提供技术方法。     

QuEChERS-液相色谱-串联质谱法检测糙米中氟唑环菌胺的残留

采用QuEChERS前处理与液相色谱-串联质谱 (LC-MS/MS) 技术,建立了糙米中氟唑环菌胺残留的分析方法。样品采用V(乙腈) : V(水)=80 : 20混合溶液涡旋提取,经PSA分散固相萃取净化,LC-MS/MS测定,外标法定量。结果表明:在0.001~0.1 mg/L范围内,氟唑环菌胺的质量浓度与对应的峰面积间线性关系良好,R2 > 0.996。在0.004、0.01和0.1 mg/kg添加水平下,氟唑环菌胺在糙米中的回收率为83%~95%,相对标准偏差 (RSD) 为3.9%~12%。以最小添加浓度确定氟唑环菌胺在糙米中的定量限 (LOQ) 为0.004 mg/kg,远低于国际食品法典委员会规定的最大残留限量 (MRL) 0.01 mg/kg。所建方法操作简单、准确度和灵敏度高,可用于糙米中氟唑环菌胺残留的检测。对中国6个省 (市) 40个糙米样品进行检测,氟唑环菌胺的残留量均低于LOQ 0.004 mg/kg。膳食风险评估结果表明,氟唑环菌胺目前在中国水稻上使用对一般人群的的健康风险很低。     

液相色谱-串联质谱同时检测水稻样品中乙基多杀菌素及其代谢物残留

采用液相色谱-串联质谱(LC-MS/MS)技术建立了同时检测水稻植株、谷壳、糙米中乙基多杀菌素及其代谢物N-demethyl-175-J和N-formyl-175-J残留的分析方法。样品采用乙腈提取,经分散固相萃取(PSA)净化,LC-MS/MS检测。结果表明:在0.02、0.2和2 mg/kg添加水平下,乙基多杀菌素及其代谢物的平均回收率在73%~105%之间,相对标准偏差(RSD)在0.9%~10%之间。乙基多杀菌素-J和-L的定量限(LOQ)分别0.016和0.004 mg/kg,代谢物的定量限(LOQ)为0.02 mg/kg。该方法操作简便、稳定和快速,可以满足水稻样品中乙基多杀菌素及其代谢物的定性与定量分析要求。     

五氟磺草胺在稻田中的消解动态及残留特性

建立了超高效液相色谱-质谱联用检测五氟磺草胺在水稻植株、稻田土壤、田水和糙米中残留的分析方法,结合田间试验研究了五氟磺草胺在稻田环境中的消解及残留特性,并对稻米中五氟磺草胺残留的膳食暴露进行了初步评估。结果表明:在0.005~0.5 mg/L范围内,五氟磺草胺的质量浓度与对应的峰面积间呈良好线性关系,检出限（LOD）为0.001~0.002 mg/kg,定量限（LOQ）为0.003~0.005 mg/kg。在0.005~0.5 mg/kg添加水平下,五氟磺草胺在水稻植株、稻田土壤、田水和糙米中的平均回收率在89%~106%之间,相对标准偏差在2.8%~8.5%之间。浙江、福建和黑龙江2年3地的田间试验表明:0.025%五氟磺草胺颗粒剂在水稻植株、稻田土壤和田水中的消解半衰期分别为1.5~3.3,3.0~4.7和1.6-3.0 d,说明该药剂在稻田环境中消解速率较快。以五氟磺草胺有效成分含量37.5和56.3 g/hm2分别施药1次,于水稻成熟期采样检测,发现其在糙米中的残留量低于0.005 mg/kg,表明其膳食摄入风险很低,该研究结果可为五氟磺草胺风险评估提供一定参考。     

快速溶剂萃取-高效液相色谱串联质谱测定水果和果汁中的多菌灵

应用快速溶剂萃取技术（ASE）-高效液相色谱串联质谱（HPLC／MS／MS）建立3种水果和3种果汁中多菌灵的新分析方法。以甲醇和氢氧化钠溶液提取,固相萃取MCx柱净化,质谱检测器检测。实验证明,多菌灵回收在92．0～96．0％,相对标准偏差在3．2～7．6％。多菌灵在样品中的最低检出浓度为2．0μg／kg。     

超高效液相色谱-串联质谱法同时检测大米中15种常用农药的残留

建立一种超高效液相色谱-串联质谱同时检测大米中甲氨基阿维菌素苯甲酸盐等15种常用农药残留的方法,考察了基质效应、提取溶剂种类、提取方法以及不同净化方法对15种农药回收率的影响。样品经V (乙腈) : V (丙酮) : V (水) = 16 : 2 : 2混合溶液匀浆提取,分散固相萃取法净化,电喷雾正离子 (ESI+) 模式电离,多反应监测 (MRM) 模式检测,外标法定量。结果表明:在0.005~1 mg/L范围内,甲氨基阿维菌素苯甲酸盐等15种农药的质量浓度与对应的峰面积间线性关系良好,相关系数 (r) ≥ 0.99;在0.01、0.1、1和4 mg/kg 4个添加水平下,15种农药在大米中的平均回收率在82%~116%之间,相对标准偏差在1.2%~12%之间 (n = 5)。方法检出限为0.000 5~0.005 mg/kg,定量限为0.01 mg/kg。用该方法对上海市郊20个批次的大米样品进行测定,均未检出农药残留超标。该方法操作简单、快速、准确,适用于大米中甲氨基阿维菌素苯甲酸盐等15种常用农药残留的同时检测。     

呋虫胺及其代谢物在水稻生态系统中的残留检测与消解动态

为评价呋虫胺在水稻生态系统中的残留与消解行为，分别在海南、湖南和黑龙江省3地进行了规范残留试验。建立了超高效液相色谱-串联质谱 (UPLC-MS/MS) 检测呋虫胺 (DNF) 及其代谢物1-甲基-3-[(3-四氢呋喃) 甲基]脲 (UF) 与1-甲基-3-[(3-四氢呋喃) 甲基]二氢胍盐 (DN) 在水稻稻株、土壤、田水、糙米和稻壳中残留的分析方法。样品经含体积分数为1%的乙酸水溶液或乙腈溶液提取，QuEChERS方法净化，以甲醇-水混合溶液为流动相梯度洗脱，多反应监测 (MRM) 模式扫描，外标法定量。结果表明:3种分析物的进样浓度与其峰面积之间呈良好线性相关，R2>0.999。DNF、UF和DN在稻株、土壤、田水、糙米和稻壳中的平均回收率在71%~102%之间，在稻株、土壤、田水和糙米中的相对标准偏差 (RSD) 在1.2%~8.3%之间，在稻壳中的RSD在4.4%~20%之间。3种分析物在稻株、土壤、田水、糙米和稻壳中的最低检测浓度 (LOQ) 分别为0.1 mg/kg、0.02 mg/kg、0.01 mg/L、0.02 mg/kg和0.1 mg/kg。DNF、UF和DN的最小检出量分别为1、0.4和4 pg。3种分析物的消解半衰期分别为:DNF在稻株上为0.41~2.7 d，土壤中为1.6~4.2 d，田水中为0.90~2.2 d；DN在稻株上为2.9~13 d，土壤中为64~65 d，田水中为4.2 d；UF在稻株上为0.43~3.1 d。20%呋虫胺悬浮剂以有效成分120~180 g/hm2的剂量于水稻抽穗期施用2~3次，施药间隔期21 d，分别于距末次施药后14 d与21 d采收，呋虫胺在糙米中的残留最大值为0.11 mg/kg，低于中国制定的其在糙米上的最大残留限量标准1 mg/kg。     

黄瓜根分泌物中的7,8-苯并黄酮及其对枯萎病发生的影响

分别提取黄瓜枯萎病感病品种津研4号和抗病品种中农10号的根分泌物,感病品种根分泌物甲醇提取液能够刺激枯萎病菌的菌丝生长,而抗病品种根分泌物甲醇提取液则抑制病原菌生长。利用LC-MS/MS技术分别对感病品种和抗病品种根分泌物中的差异物质进行分析鉴定。与感病品种津研4号相比,抗病品种中农10号根分泌物中含有7,8-苯并黄酮(7,8-BF),含量为0.02μg/株。50μg/mL的7,8-BF能够显著抑制黄瓜枯萎病菌菌丝生长和孢子萌发,而100μg/mL的7,8-BF能显著抑制抗感品种侧根形成,但是抗病品种的耐受力高于感病品种。用7,8-BF处理黄瓜种子,枯萎病侵染程度显著降低。当7,8-苯并黄酮浓度为50μg/mL时,感病品种病情指数从71.7降为30.8,达到中抗水平。     

HPLC/MS/MS测定铁皮石斛中咪鲜胺残留

用高效液相色谱-质谱联用法定量检测铁皮石斛中的咪鲜胺残留,用乙腈提取铁皮石斛植株中的残留咪鲜胺,分析色谱柱为C_(18)(100mm×2.1mm×2.6μm),以甲醇和乙酸铵溶液梯度洗脱,采用选择离子监测模式,以保留时间和质荷比对咪鲜胺予以定性确认,以m/z=308.07为检测定量离子。咪鲜胺出峰时间在3.87min左右,方法检出限为0.52μg/kg,平均回收率在89.2%~114.7%之间。该方法灵敏、准确、定量范围宽、耐用性强,可作为铁皮石斛中咪鲜胺残留的可靠检测方法 。     

QuEChERS-高效液相色谱-串联四极杆飞行时间质谱法同时测定大米中7种除草剂残留

建立了同时测定大米中西草净、异丙隆、苄嘧磺隆、莎稗磷、乙氧氟草醚、草酮和二甲戊灵7种除草剂残留的QuEChERS-高效液相色谱-串联四极杆飞行时间质谱 (HPLC-MS/MS Triple TOF) 方法。样品经V (乙酸乙酯) : V (水) = 80 : 20混合溶液提取，以N-丙基乙二胺 (PSA) 为吸附剂进行基质分散萃取净化，采用HPLC-MS/MS Triple TOF检测，外标法定量。结果表明:7种除草剂在一定的质量浓度范围内，其峰面积与对应的质量浓度间线性关系良好，相关系数均大于0.99；西草净、异丙隆、苄嘧磺隆和莎稗磷在0.001、0.01、0.05 mg/kg 3个添加水平下的平均回收率在75%~108%之间，相对标准偏差 (RSD) 在1.1%~7.0% (n = 5) 之间，定量限 (LOQ) 均为0.001 mg/kg；乙氧氟草醚、草酮和二甲戊灵在0.01、0.05和1 mg/kg 3个添加水平下的平均回收率在81%~108%之间，RSD在2.7%~9.0%之间，LOQ均为0.01 mg/kg。该方法样品前处理简单快速，方法灵敏度、准确度和精密度均符合农药残留检测要求，可用于大米中西草净、异丙隆、苄嘧磺隆、莎稗磷、乙氧氟草醚、草酮和二甲戊灵残留的同时检测。     

质谱法在食品样本农药残留分析中的应用进展

质谱法(Mass spectrometry,MS)是当前农药残留分析中的主导检测技术。对气相色谱-质谱法(GC-MS)、气相色谱-串联质谱法(GC-MS/MS)、液相色谱-串联质谱法(LC-MS/MS)和飞行时间质谱法(time-of-flight mass spectrometry,TOF-MS)在食品样本农药残留分析中的应用进行了综述,重点对质谱技术在国内外多残留分析方法研究中的应用进展进行了总结和归纳,简要比较了质谱分析时常用的几种样品前处理技术的优缺点及其适用性,展望了质谱法在农药残留分析研究领域的发展前景。     

What proteomic analysis of the apoplast tells us about plant–pathogen interactions

Plant pathogens have developed different strategies during their evolution to infect and colonize their hosts. In the same way, plants have evolved different mechanisms acting against potential pathogens trying to infect and colonize their tissues. Regulation of a wide variety of proteins is required in order to perceive the pathogen and to activate the plant defence mechanisms. The apoplast is the first compartment where these recognition phenomena occur in most plant–pathogen interactions, allowing the exchange of different molecules and facilitating inter‐ and intracellular communication in plant cells. Proteomic analysis of the apoplast in recent years has found the initial biochemical responses involved in pathogen recognition and early defence responses. However, this proteomic approach requires some specific experimental conditions to obtain an extract free of cytoplasmic proteins and nonprotein contaminants that affect the subsequent stages of separation and quantification. Obtaining the highest proportion of proteins from the apoplastic space in infected tissues requires different steps such as extraction of apoplastic washing fluids and preparation of total secreted proteins (protein precipitation, solubilization, separation and digestion). Protein identification using mass spectrometry techniques and bioinformatics tools identifying peptides for the extracellular exportation is required to confirm the apoplastic location. This review compiles the most commonly used techniques for proteomic studies, focusing on the early biochemical changes occurring in the apoplast of plants infected by a wide range of pathogens. The scope of this approach to discover the molecular mechanisms involved in the plant–pathogen interaction is discussed.     

生物样品中水胺硫磷的气质联用分析

水胺硫磷为高毒有机磷类农药，本文建立了水胺硫磷的液-液提取方法，采用气质联用技术(GC／MS)对血液中水胺硫磷成分进行了分析与解谱，并确定了水胺硫磷各离子碎片的归属，本方法在1～100ng／μL之间呈线性，线性相关系数R=0．9984，平均回收率为92．5％，相对标准偏差(RSD)为2．1％。