嘧霉胺和乙霉威在大葱中的残留消解动态

建立了大葱中嘧霉胺和乙霉威残留的检测方法,并测定了嘧霉胺和乙霉威在春季大葱中的残留消解动态和最终残留量 。大葱样品经乙腈提取,SAX/PSA固相萃取柱净化,气相色谱-质谱选择离子 (GC/MS/SIM)检测 。结果表明, 建立的大葱中嘧霉胺和乙霉威残留量检测方法在0.001 ~0.1 mg/kg和0.01 ~0.1 mg/kg水平的平均添加回收率为97.8% ~107.2%,相对标准偏差为2.7% ~7.4%,嘧霉胺和乙霉威的检出限分别为0.000 3和0.003 mg/kg,方法的定量限分别为0.001和0.01 mg/kg。田间残留试验结果表明,嘧霉胺和乙霉威在大葱中消解较快,半衰期分别为4.1和3.1 d,药后14 d消解率均达90%以上;26% 嘧霉·乙霉威可湿性粉剂(嘧霉胺和乙霉威质量比为10∶ 16)按推荐高剂量1 800 g/hm2(嘧霉胺有效成分180 g/hm2,乙霉威有效成分288 g/hm2)和2倍剂量3 600 g/hm2 对水喷雾2~3次,末次施药后7,14,21 d,嘧霉胺在大葱中的最终残留量为0.007~0.560 mg/kg,乙霉威在大葱中的最终残留量为ND~0.394 mg/kg,均低于日本规定的最大残留限量(MRL) 2.0和5.0 mg/kg。     

茚虫威在菜用大豆上残留动态及安全使用技术

采用气相色谱法(GC/ECD)研究了菜用大豆中茚虫威残留量的检测方法,以及茚虫威在菜用大豆上的残留消解动态,并对其安全使用技术进行了示范试验。结果表明,建立的菜用大豆中茚虫威残留量定量检测方法的平均回收率为86.8% ~90.1%,相对标准偏差为3.85% ~5.24%,最小检出量0.01 ng,最低检测浓度为0.005 mg/kg,该方法简便、准确、能满足实际样品分析。茚虫威在菜用大豆上的原始沉积量因不同施药处理有所差异,施用有效成分96.43 g/hm2的原始沉积量＞施用有效成分48.21 g/hm2的原始沉积量,间隔期7 d连续施药两次的原始沉积量＞施药1次;残留消解动态符合一级动力学方程,早季的消解系数(︱k︱)=0.174 75±0.000 15,半衰期(T1/2)为4.0 d,消解99%所需要的时间(T0.99)为26.3 ~26.4 d;晚季︱k︱=0.108 35±0.004 95,T1/2为6.1 ~6.7 d,T0.99为40.6 ~45.5 d。在安全使用技术示范试验区,茚虫威按常规施药量(有效成分67.50 g/hm2)及施药方法,2006年晚季施药1次与间隔期7 d连续施药两次,在末次施药后25 d、30 d,最终残留量分别为0.065 ~0.102 mg/kg和0.032 ~0.081 mg/kg;2007年早季间隔期7 d 连续施药两次,在第2次施药后15 d,最终残留量为0.097 ~0.132 mg/kg,产品质量安全水平均符合日本规定的MRL(0.2 mg/kg)要求。     

二氯吡啶酸在小麦和土壤中的残留分析方法

本文研究了小麦和土壤中二氯吡啶酸残留量的气相色谱分析方法。当样品中二氯吡啶酸的添加浓度为0.01、0.1、1.0mg/kg时,样品的平均回收率为86.2%～100.4%,变异系数为2.76%～10%;该方法的最小检出量为1.25×10-11g,最低检测浓度为0.001mg/kg。     

茚虫威在金银花中的残留动态研究及安全性评价

为了探明茚虫威在金银花中的残留特性和安全性,对茚虫威在金银花中的消解动态及最终残留进行了研究。样品经乙腈提取,超高效液相色谱-串联质谱(UPLC-MS/MS)检测,外标法定量。运用所建立的方法对茚虫威在山东泰安、河北邢台、浙江杭州、湖南邵阳、广东湛江和重庆九龙坡6个试验点的金银花中的残留消解动态和最终残留进行了研究。试验结果表明:茚虫威残留量在金银花中随时间延长而递减,符合一级反应动力学方程,消解速度较快,半衰期为1.5～2.2 d,属易消解型农药。参照中国制定的茶叶中茚虫威的最大残留限量(MRL)5 mg/kg,15%茚虫威悬浮剂按推荐使用剂量90 g/hm~2,施药1次,施药后7 d,所采收的金银花中的茚虫威残留量低于5 mg/kg。研究结果可为茚虫威在金银花上的合理使用及其最大残留限量制定提供参考。     

14种杀虫剂对草地贪夜蛾的杀卵活性

为筛选对草地贪夜蛾卵具有活性的杀虫剂,为防治卵期草地贪夜蛾提供数据支撑。采用浸渍法,室内测定了14种杀虫剂的杀卵活性。结果表明:14种杀虫剂均具有一定的杀卵活性。在100 mg/L浓度下,苯氧威、灭多威和吡丙醚的杀卵活性最强,显著高于其余药剂,且能够完全抑制卵的孵化。甲氨基阿维菌素苯甲酸盐(甲维盐)、氟虫脲、硫双威、氟铃脲、除虫脲和溴氰虫酰胺的杀卵效果无显著差异(P0.05),杀卵活性在71.67%～90.00%之间。在10 mg/L浓度下,苯氧威和吡丙醚杀卵活性最高,可完全抑制卵的孵化。甲维盐、除虫脲和溴氰虫酰胺也表现出较好的杀卵效果,杀卵活性介于55%～66.67%之间,以上药剂均可作为草地贪夜蛾的杀卵剂轮换使用。值得注意的是,茚虫威是一种对鳞翅目害虫具有优异杀虫活性的新型杀虫剂,且对环境友好。其在100 mg/L和10 mg/L处理浓度下对草地贪夜蛾杀卵活性为52.38%±6.25%和36.67%±6.67%。甲氧虫酰肼在两个处理浓度下的杀卵活性均低于30%,不推荐作为草地贪夜蛾的杀卵剂。上述结果可为草地贪夜蛾的有效防治提供参考。     

气相色谱-电子捕获检测器同时测定瓜果类蔬菜中15种除草剂残留

采用气相色谱-电子捕获检测器（GC-ECD）法建立了同时测定瓜果类蔬菜中15种除草剂（氟嘧磺隆、草毒死、敌草隆、氯草定、氟乐灵、炔苯酰草胺、乙草胺、甲草胺、异丙甲草胺、吡唑草胺、硝草胺、丁草胺、丙草胺、齅草酮、吡氟酰草胺）残留量的方法。供试番茄、黄瓜、青椒、茄子、西葫芦、马铃薯、芸豆及萝卜8种样品经乙酸乙酯与二氯甲烷混合溶剂提取,Florisil PR固相萃取柱净化,DM-1毛细管气相色谱柱（30 m×0.32 mm,0.25 μm）分离,GC-ECD测定,外标法定量。结果表明:在0.002~0.5 mg/kg的3个添加水平下,15种除草剂在8种蔬菜中的平均添加回收率为77%~113%,相对标准偏差（RSD）为3.5%~10.8%,定量限为0.001~0.1 mg/kg。采用所建立的方法对市售蔬菜样品进行测定,结果表明,15种除草剂的残留量均小于最大允许残留限量。该方法简单、快速,灵敏度高,适用于同时测定瓜果类蔬菜样品中15种除草剂的残留量。     

气相色谱法测定敌敌畏在水稻中的残留

建立了气相色谱(GC-NPD)检测敌敌畏在水稻中残留量的方法。在优化样品前处理方法的基础上,选用DB-35(30m×0.32mm×0.25μm)毛细管色谱柱测定水稻植株、糙米、稻壳、土壤及田水样品中敌敌畏的含量。结果表明,在0.01~1.0mg/kg添加水平范围内,敌敌畏的平均添加回收率为82.2%~106.8%,相对标准偏差(RSD)为0.25%~3.67%,5%(n=5)。该方法操作简便,杂质干扰少,灵敏度、准确度高。     

25%苯氧威水分散粒剂的GC和HPLC分析方法研究

本文采用气相色谱法和高效液相色谱法2种方法对苯氧威进行定量分析,气相色谱法中选用CP-8751毛细管柱,以磷酸三苯酯为内标,用FID检测器对苯氧威进行分离和定量;液相色谱法中使用Chromatorex C18不锈钢柱,以甲醇 水为流动相,紫外检测器对苯氧威进行分离和定量。2种方法的标准偏差分别为0.076和0.088,变异系数分别为0.30%和0.35%,平均回收率分别为99.67%和99.81%,线性相关系数分别为0.999 8和0.999 9。     

30%茚虫威悬浮剂防治稻纵卷叶螟效果

每667 m~2用30%茚虫威悬浮剂15 g、30%茚虫威悬浮剂15 g+1.8%阿维菌素乳油20 g、15%多杀·茚虫威悬浮剂15 g防治稻纵卷叶螟,在稻纵卷叶螟第四代卵孵化高峰期施药,对稻纵卷叶螟的防治效果较好。     

QuEChERS-高效液相色谱-串联质谱法检测氟吡菌胺及其代谢物和霜霉威在叶用莴苣中的残留及消解动态

样品通过改良的QuEChERS方法提取净化,建立了高效液相色谱-串联质谱检测叶用莴苣Loctuca sativa L.var.ramosa Hort.中氟吡菌胺及其代谢物2,6-二氯苯甲酰胺和霜霉威残留量的分析方法.样品经乙腈提取,多壁碳纳米管净化,基质匹配标准溶液外标法定量.结果显示:在0.005～1 mg/L范围内...     

莠去津在土壤中的残留试验研究

本文介绍了莠去津在土壤中的残留消解动态试验及其检测方法和检测结果。     

Field susceptibility of the cocoa mirid,Sahlbergella singularis haglund (heteroptera) to some new insecticides

Two groups of insecticides were screened against the cacao mirid, S. singularis in small-scale field trials from September 1969 to January 1972. In first group 0.05% promecarb, 0.04% phosphamidon and 0.02% monocrotophos were equally effective and superior to 0.05% mecarbam in the three days after spraying but 0.05% promecarb was most toxic to bugs by the seventh day. In the 0.15 to 0.2% range, all four insecticides showed similar toxicity within 3 days of spraying but only 0.15% mecarbam and 0.2% promecarb maintained control to the seventh day. For mecarbam, phosphamidon and monocrotophos, control at 0.15% was better than at 0.05, 0.04 and 0.02% respectively 7 days after spray whilst 0.2% was superior to 0.05% promecarb 2 days after spray and not afterwards. At either 0.21 or 0.33 lb/acre insecticides in the second group (pirimiphos methyl, HOE 2960, CA 6900 and dicrotophos) gave identical level of control of mirids and control at the latter dosage rate was not better than at the former. There was no significant difference between 3 and 4 oz a.i./10 gal water/200 trees in toxicity to mirids and the insecticides gave equally good control of the bugs at both dosage levels till 35th day after spray. On the basis of efficacy and safety of use, promecarb CA 6900 and pirimiphos methyl were deemed suitable for further (large scale) trials.     

气相色谱法测定元胡、浙贝母和白芍中嘧霉胺残留

建立了一种测定元胡、浙贝母和白芍3种中药材中嘧霉胺残留的气相色谱分析方法。样品经二氯甲烷提取,液-液分配,柱层析[m（中性氧化铝）:m（弗罗里硅土）=3:2]净化,气相色谱-氮磷检测器（GC-NPD）检测,基质匹配外标法定量,同时经气相色谱-串联质谱（GC-MS/MS）验证。结果表明:在0.02~10 mg/L范围内,分别以正己烷和3种空白基质溶液为溶剂配制嘧霉胺的标准工作溶液,峰面积与相应的质量浓度间呈良好的线性关系,R2均大于0.999;在0.01（元胡中为0.02）、0.1和0.5 mg/kg 3个添加水平下,添加回收率为75%~104%,日内相对标准偏差（RSD）为1.3%~10.2%（n=5）,日间RSD为1.2%~9.0%（n=3）。分析方法在元胡、浙贝母和白芍中的定量限（LOQ）分别为0.02、0.01和0.01 mg/kg。该方法的灵敏度、准确度及精密度均符合农药残留分析要求,且简单易行,净化效果好,适用于元胡、浙贝母和白芍中嘧霉胺分析。     

叶菌唑在小麦中的残留消解及膳食风险评价

为评价叶菌唑在小麦中的残留行为及其产生的膳食摄入风险,于北京、安徽及黑龙江进行了1年3地田间试验,建立了叶菌唑在小麦中的残留分析方法,并对我国不同人群的膳食暴露风险进行了评价。样品用乙腈提取,经Florisil固相萃取柱净化,气相色谱-氮磷检测器(GC-NPD)检测,外标法定量。结果表明:在0.02~10 mg/kg的添加水平下,叶菌唑在小麦籽粒和植株中的平均回收率在81%~101%之间,相对标准偏差(RSD)在2.1%~9.1%之间;其在小麦籽粒和植株中的定量限(LOQ)分别为0.02和0.04 mg/kg。叶菌唑在小麦植株中的消解符合一级动力学方程,半衰期为4.9~7.3 d。收获时小麦籽粒中叶菌唑的最大残留量为0.037 mg/kg,低于美国和欧盟设定的最大残留限量(MRL)0.15 mg/kg。针对我国不同人群的膳食摄入及风险评估暴露,风险商值(RQ)在0.001~0.002之间,表明叶菌唑在小麦中的膳食摄入风险较低。     

Determination of residues of promecarb and its metabolite, 3-methyl-5-isopropylphenol,in cattle

A procedure is described for the colorimetric determination of promecarb as 3-methyl-5-isopropylphenol in tissues using 2,6-dichlorpbenzoquinone-4-chlorimine as the chromogen. Cattle were exposed to either 1, 3, 5 or 8 spray applications of a 0·2% promecarb emulsion at 3-day intervals or were fed promecarb at 2 ppm or 20 ppm daily in the diet for 20 days. All animals were slaughtered 30 h after final exposure. Of the animals in the spraying trial, residues in omental fat ranged from 0·9 ppm to 1·5 ppm promecarb and 0·4 ppm to 1·9 ppm 3-methyl-5-isopropylphenol. Residues in perirenal fat ranged from 0·8 ppm to 1·9 ppm promecarb and 0·9 ppm to 1·6 ppm 3-methyl-5-isopropylphenol. Residues in diaphragm muscle did not exceed 0·06 ppm. In the feeding trial, the maximum residues induced were 2·2 ppm promecarb and 1·4 ppm 3-methyl-5-isopropylphenol in omental fat of an animal fed for 20 days on a diet containing 20 ppm promecarb.     

异丙隆在水稻和稻田土壤、水中的残留量和降解动态研究

研究异丙隆在水稻、土壤、田水中的残留分析方法及其消解动态和最终残留量。样品以丙酮提取、净化后采用气相色谱法-氮磷检测器（GC—NPD）毛细管柱进行测定。水田添加0．005、1．00mg／kg，土壤、水稻添加0．05、1．00mg／kg，添加回收率在77．9％-118．4％之间，变异系数为2．1％～11．2％。异丙隆在田水、土壤的消解动态没有明显差异，平均半衰期分别为413、5-3d，在稻秆中消解较慢，平均半衰期为8．3d。异丙隆24％可湿性粉剂，按900ga．i.／hm^2用量，在直播水稻田水稻播种后施药1次，收获时异丙隆在土壤、稻杆和稻谷中的残留量均低于0．05mg／kg。     

两种蔬菜中甲胺磷、氧乐果和克百威的残留量分析

分别选取一种瓜菜 (黄瓜 )和一种叶菜 (生菜 ) ,选择了两种有机磷 (甲胺磷、氧乐果 )和一种氨基甲酸酯类 (克百威 )农药 ,对这 3种农药在两种蔬菜中的残留测定方法进行了研究。采用弗罗里硅土柱提取的方法进行前处理 ,淋洗液浓缩后用 GC- NPD测定 ,建立了一种简便快速的检测方法 ,并采用该方法对实际处理样本进行了测定。从方法添加回收率和实测数据可以看出 ,该方法净化提取效果好 ,结果平行性好 ,灵敏度较高 ,是一次快速准确测定蔬菜中农药残留的成功尝试。     

An optimized screening method for identifying levels of resistance to Crinipellis perniciosa in cocoa (Theobroma cacao)

The effects of host age, leaf number, host type (clone or seedling), pathogen spore concentration and incubation time on inoculation with Crinipellis perniciosa (witches' broom disease of cocoa) were studied in greenhouse experiments using susceptible cocoa genotypes. Three methods of inoculation (agar-drop, water-drop and spray) were also tested. An optimized inoculation method was selected and tested for its repeatability as well as its ability to discriminate between various levels of resistance to C. perniciosa in cocoa. The optimized method (350 000 viable basidiospores per mL, 60 h incubation, agar-drop technique) produced 100% infection repeatedly, on both clonal and seedling plants of a susceptible genotype. Seedling age (2–12 months) and leaf number did not significantly affect the percentage of plants with symptoms or broom characteristics. This method discriminated effectively between the various levels of resistance in 14 cocoa genotypes and is recommended as an inoculation method to identify levels of resistance in germplasm collections. Symptom severity was shown to be a better measure of resistance than infection success.     

Effect of different formulations on tebuconazole residues in stone fruits

BACKGROUND: The correlation between pesticide residue levels and formulation of an active substance is often not considered, even if it is reasonable to expect some differences arising from behaviour during dilution and spraying, from adhesion to plant and from degradation. An experimental study to investigate the magnitude of tebuconazole residues as a function of different tebuconazole formulated products was carried out in Italy. The fungicide was applied as wettable powder (WP) and water‐dispersible granule (WG) formulations to peach, plum, apricot and nectarine orchards, on four different sites. The fruit samples gained from the field trials were quantitatively analysed by gas chromatography with a nitrogen phosphorus detector (GC/NPD) for tebuconazole residues. RESULTS: Tebuconazole residues in the fruits gained from the plot treated with the WP formulation, 14 days after application, were in the range 0.01–0.07 mg kg^?1, while corresponding residues in the plot treated with the WG formulation were in the range 0.01–0.06 mg kg^?1. CONCLUSION: No significant differences in the residue levels of tebuconazole could be observed between the trials conducted with the WP and the WG formulation. Copyright © 2009 Society of Chemical Industry     

三甲基硅重氮甲烷衍生化-气相色谱法测定水果蔬菜中乙烯利的残留

针对水果蔬菜中乙烯利的残留,建立了三甲基硅重氮甲烷衍生化-气相色谱的分析方法。样品用 V (甲醇) : V (盐酸) = 9:1的溶液提取,无水乙醚萃取,三甲基硅重氮甲烷衍生化15 min,采用气相色谱-质谱法定性,气相色谱仪-火焰光度检测器 (GC-FPD) 检测,外标法定量。结果显示:在0.01~2 mg/L范围内,乙烯利的质量浓度与其对应的峰面积间线性关系良好,相关系数大于0.999 6;此方法检出限为0.01 mg/kg,定量限为0.03 mg/kg;在辣椒、番茄、香蕉、苹果和梨的空白果蔬样品中分别添加0.01、0.1和1 mg/kg 3 个水平下,回收率为93%~102%,相对标准偏差为4.2%~7.3%。该方法准确度和灵敏度高,抗干扰能力强,能准确并快速测定出水果、蔬菜中乙烯利的残留量。