丁醚脲在棉花及土壤中的残留消解动态

[目的]为评价丁醚脲在棉花上使用后的环境安全性,在商丘和杭州2地进行了其在棉花上的残留动态和最终残留试验。[方法]样品用乙腈提取,乙酸铵和NaCl液液分配,PSA结合GCB净化,后经LC-MS/MS测定其残留量。[结果]丁醚脲在棉叶上的半衰期为0.8~1.1 d;在土壤中的半衰期为1.4~1.9 d;最后1次施药后间隔7、14、21 d棉籽中丁醚脲的残留量均≤0.005 mg/kg。[结论]建议13%联苯·丁醚脲乳油防治棉花红蜘蛛,在推荐剂量下最多施药1次,安全间隔期为7 d。     

噻苯隆和敌草隆在棉花中的残留消解动态及残留量

建立高效液相色谱质谱联用(HPLC-MS/MS)方法测定噻苯隆和敌草隆在棉花中的残留,对噻苯隆和敌草隆在棉花和土壤中的残留降解进行研究。结果表明:添加质量分数为0.01~10.0mg/kg时,噻苯隆和敌草隆在棉籽、土壤和棉叶中的平均添加回收率为77.5%~101.1%,相对标准偏差为1.4%~9.2%。噻苯隆在棉叶和土壤中的半衰期分别为2.2~3.4 d、11.1~16.8 d。敌草隆在棉叶和土壤中的半衰期分别为2.5~3.3 d、11.4~18.9 d。当540 g/L噻苯·敌草隆悬浮剂有效成分用量为97.2~145.8 g/hm~2,喷雾施药1次,棉籽中噻苯隆和敌草隆的残留量均为未检出(0.01 mg/kg)。该方法快速简便,准确可靠。     

多杀霉素在甘蓝和土壤中的残留分析及消解动态

[目的]为25%多杀霉素悬浮剂在甘蓝上的安全合理使用提供可靠依据。[方法]建立多杀霉素在甘蓝和土壤中的残留检测方法,并测定在甘蓝和土壤中的消解动态和最终残留。[结果]方法的准确度和精密度符合残留检测要求,在甘蓝中消解半衰期为1.7~2.6 d,在土壤中消解半衰期为1.6~2.3 d。按剂量200、300 ga.i./hm2,施药3~4次,间隔7 d,末次施药后7 d,在甘蓝中的残留量0.08 mg/kg,在土壤中的残留量0.05 mg/kg。[结论]建立的检测方法准确可靠,甘蓝收获时残留量低于中国规定的最大残留限量(MRL)。     

20%啶虫脒可溶液剂在棉花和土壤中的残留及消解动态

[目的]评价啶虫脒在棉花和土壤中使用的安全性,建立其使用规范。[方法]采用田间试验及液质联用检测方法,研究了啶虫脒在棉花和土壤中的残留消解动态,并对其在棉花上使用的安全性提出了建议。[结果]啶虫脒在棉花和土壤中的消解较快。棉叶中半衰期为2.14～5.37 d,土壤中半衰期0.88～8.87 d。20%啶虫脒可溶液剂防治棉花蚜虫,用药量30～45 g a.i./hm2,棉花收获前49 d开始施药,末次施药后7、14、21 d采集棉籽及土壤样品,检测的棉籽及土壤中啶虫脒的残留量均低于0.05 mg/kg。[结论]拟推荐我国啶虫脒在棉花和土壤中的最大残留限量为0.2 mg/kg。     

代森联和乙撑硫脲在西瓜和土壤中的消解及安全性评价

[目的]研究代森联和乙撑硫脲在西瓜和土壤中的消解与残留变化趋势,评价代森联和乙撑硫脲在西瓜上使用的安全性。[方法]样品经液相色谱测定。[结果]西瓜中代森联的原始沉积量为1.19~2.01 mg/kg,半衰期(t1/2)为4.2~9.0 d;土壤中代森联的原始沉积量为1.02~2.83 mg/kg,t1/2为4.6~5.4 d。用药0.042 d后,乙撑硫脲在西瓜中的残留量为0.07~0.13 mg/kg,t1/2为2.2~2.9 d;在土壤中的残留量为0.07~0.19 mg/kg,t1/2为2.6~2.8 d。施药间隔7、14、21 d,代森联在西瓜、瓜瓤和土壤中的残留量1.0 mg/kg,乙撑硫脲在西瓜、瓜瓤和土壤中的残留量0.02 mg/kg。[结论]参照我国规定代森联在西瓜上的最大残留限量(MRL)为1 mg/kg,以及欧盟规定乙撑硫脲在植物性食品上的MRL为0.05 mg/kg的标准,60%吡唑醚菌酯·代森联可分散粒剂按推荐剂量和方法使用,间隔7 d后的西瓜是安全的。     

嗪草酮在马铃薯和土壤中的残留分析方法及消解动态

[目的]建立测定马铃薯、马铃薯植株及土壤中嗪草酮残留量的高效液相色谱-串联质谱(HPLC-MS/MS)方法,研究嗪草酮在马铃薯和土壤中的消解动态及最终残留。[方法]采用Qu ECh ERS前处理方法-高效液相色谱串联质谱法检测马铃薯及植株和土壤中的嗪草酮残留量。[结果]嗪草酮在马铃薯、马铃薯植株和土壤中的平均回收率分别为90.4%~97.4%、86.7%~98.7%、89.1%~97.3%,相对标准偏差(RSD)分别为1.4%~4.3%、0.8%~4.8%、0.6%~3.9%。嗪草酮在马铃薯植株中的消解半衰期为0.9~1.6 d;在土壤中的消解半衰期为5.7~6.6 d,属于易降解农药。[结论]该方法简单可靠,符合农药残留分析要求,可用于马铃薯和土壤中嗪草酮的残留检测。     

哒螨灵在棉花和土壤中的残留及消解动态研究

研究了哒螨灵在棉花和土壤中的残留及消解动态,采用气相色谱-电子捕获检测器进行定量分析。哒螨灵在棉籽、棉花叶及土壤中添加平均回收率为82.36%~113.94%,相对标准偏差为1.76%~8.07%。其最小检出量为1×10-11 g,在棉籽、棉花叶及土壤中的最低检测浓度均为0.01mg/kg。2011和2012年在河南省和湖南省的田间残留试验结果表明:哒螨灵在棉花叶中的消解半衰期为0.84~2.5 d,土壤中的消解半衰期为5.7~7.3 d;哒螨灵在棉籽中的最终残留量均≤0.01mg/kg,说明该药为低残留、易消解农药。建议采用10%哒螨灵微乳剂防治红蜘蛛,最高有效成分用量为112.5 g/hm2,最多施药3次,安全间隔期为14 d。     

20%啶虫脒·哒螨灵微乳剂在棉花和土壤中的残留检测及消解动态分析

[目的]对20%啶虫脒·哒螨灵微乳剂在棉花和土壤中的安全性进行评价,为该农药在棉花上的合理使用提供重要的科学依据。[方法]气相色谱-电子捕获检测器进行定量分析,研究啶虫脒、哒螨灵在棉籽、棉花叶和土壤中的残留及消解动态。[结果]2011、2012年在河南和浙江2地田间残留试验结果表明:啶虫脒在棉花叶和土壤中的消解半衰期分别为3.8~8.9、2.9~6.2 d;哒螨灵在棉花叶和土壤中的消解半衰期分别为0.49~1.3、5.3~7.6 d;不同采样间隔及施药次数,啶虫脒在棉籽中的最终残留量均≤0.005 mg/kg,哒螨灵在棉籽中的最终残留量均≤0.01 mg/kg。[结论]该药为低残留、易消解农药,建议20%啶虫脒·哒螨灵微乳剂防治棉花蚜虫,最高用药量30 g a.i./hm2,最多施药2次,安全间隔期为15 d。     

高效液相色谱-串联质谱法测定烯啶虫胺在甘蓝和土壤中的残留及消解动态

[目的]采用高效液相色谱-串联质谱法建立了烯啶虫胺在甘蓝和土壤中的残留分析方法,并研究了烯啶虫胺在甘蓝和土壤中的消解动态及最终残留。[方法]样品经乙腈2次提取后,直接进HPLC-MS/MS检测。[结果]烯啶虫胺在甘蓝及其土壤中的添加回收率为81.7%~104.2%,相对标准偏差为1.6%~4.7%,定量限(LOQ)为0.02 mg/kg。消解动态和最终残留试验结果表明,烯啶虫胺在甘蓝和土壤中的消解半衰期分别为0.7~1.9、4.3~6.2 d,甘蓝最终残留样品中的残留量均低于最低检测浓度(0.02 mg/kg),土壤最终残留样品中的残留量为0.02~0.174 mg/kg。     

热带气候下联苯菊酯在甘蓝和土壤中的残留降解动态

研究热带气候下联苯菊酯在甘蓝和土壤中的消解动态和最终残留。样品经乙腈萃取净化后采用毛细管气相色谱法-电子捕获检测器(GC-ECD)进行测定。结果表明,联苯菊酯在甘蓝和土壤中消解速度较快,测得第一次试验,甘蓝中半衰期为7.70d,土壤中半衰期为10.55d,第二次试验,甘蓝中半衰期为8.97d,土壤中半衰期为12.29d。以最大推荐施用剂量和2倍最大推荐施用剂量施用,不同处理测得在最后一次施药后7d甘蓝样品中最大残留量为0.052mg/kg,土壤样品中最大残留量为0.193mg/kg。分析结果表明联苯菊酯是一种使用安全的杀虫杀螨剂。     

40%乙草胺·扑草净悬浮乳剂防除棉花田杂草田间试验

研究了40%乙草胺·扑草净悬浮乳剂对棉花田杂草防除效果,同时研究了该剂对棉花品质的影响。试验结果表明,40%乙草胺·扑草净悬浮乳剂对棉花田杂草具有良好的控制效果,200～250mL/667m2用药后50d对杂草株防效和鲜重防效都在94%以上。试验还表明,40%乙草胺·扑草净悬浮乳剂对棉花品质没有不良影响。     

灭多威在棉花及土壤中降解动态及残留量研究

按生产上常规用量，每亩喷施２０％灭多威乳油６０毫升防治二代棉铃虫，施药后７天在棉叶上及１４天在土壤中其降解率分别为９８．８１％及８８．０９％；半衰期分别的１．５６天及４．９８天。防治二、三、四代棉铃虫，按有效剂量施药６次，有效成分７２克／亩，棉籽和土壤中的最大残留量分别为０．０２３及０．０８４微克／克；再加大５０％用量，有效成分１０８克／亩，最大残留量仅为０．０３４及０．２１４微克／克。结果表明，灭多威在棉叶上及土壤中降解较迅速，常规用量下，对棉籽及土壤污染较轻。     

Controlled release study of carbaryl insecticide from calcium alginate and nickel alginate hydrogel beads

In this study, controlled release formulations for reducing environmental impact of pesticides have been produced by encapsulating as a model pesticide carbaryl (Carb) in the alginate beads. The various hydrogel bead formulations were prepared by the ionotropic crosslinking of sodium alginate (NaAlg) with calcium and nickel ions. The surface morphology of prepared beads was characterized with scanning electron microscopy (SEM). SEM confirmed the spherical nature and surface morphology of the particles. Bead characteristics, such as carbaryl entrapment efficiency, particle size, equilibrium swelling degree, and carbaryl release kinetics, were determined. The effects of the bead preparation conditions such as crosslinker concentration and type, carbaryl/sodium alginate (Carb/NaAlg) ratio and percentage of NaAlg on the carbaryl release from the calcium alginate (Ca‐Alg) and nickel alginate (Ni‐Alg) beads were investigated in distilled water at 25°C. It was observed that carbaryl release from the Ca‐Alg beads was slower than that of Ni‐Alg beads. The release results indicated that carbaryl release from both of the Ca‐Alg and Ni‐Alg beads decreases with the increasing crosslinker concentration, Carb/NaAlg ratio and percentage of NaAlg. The highest carbaryl release was found to be 100% for the Ni‐Alg beads at 3 days whereas the lowest carbaryl release was found to be 67% for the Ca‐Alg beads at 21 days. The swelling measurements of the beads were also in consistent with the carbaryl release results. The carbaryl release from most of the bead formulations followed Case II transport. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Relationships between cotton leaf-derived volatiles and growth ofAspergillus flavus

Microbial-free compressed air was passed continuously for 2- and 7-day test periods through enclosed systems containing wounded or nonwounded leaves of glanded or glandless cotton; the resultant emitted volatiles were bubbled through liquid cultures ofA. flavus. After two days incubation, volatiles from wounded glanded and wounded glandless cotton leaves retarded the growth ofA. flavus. After seven days incubation, fungal growth was stimulated in cultures which received volatiles from wounded or nonwounded glanded cotton leaves, but not from either type of glandless cotton leaves. Volatile profiles of the leaves were obtained by GC/MS examinations of the leaves at 2- and 7-day time periods. Purified compounds of selected identified volatiles were assayed withA. flavus to determine which volatiles might be responsible for the bioactivity described.     

Controlled release of insecticide carbaryl from sodium alginate,sodium alginate/gelatin,and sodium alginate/sodium carboxymethyl cellulose blend beads crosslinked with glutaraldehyde

Interpenetrating network polymeric beads of sodium alginate (NaAlg) and its blend with gelatin (gels) or sodium carboxymethyl cellulose (NaCMC) have been prepared by crosslinking with a common crosslinking agent, glutaraldehyde (GA), for the release of insecticide carbaryl (Carb). The prepared beads were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Scanning electron microscopy confirmed the spherical nature and surface morphology of the particles. Bead characteristics, such as carbaryl entrapment efficiency, particle size, equilibrium swelling degree, and carbaryl release kinetics, were determined. The effects of the preparation conditions, such as Carb/NaAlg ratio, time of exposure to GA, blend ratio, and temperature of release medium on the carbaryl release, were investigated for 25 days at 25°C. It was observed that the carbaryl release decreased with increase in crosslinking of network, while it increased with increase in Carb/NaAlg ratio and temperature. The release of carbaryl also increased with increase in Gel or NaCMC content in the blend beads. The highest carbaryl release was found to be 100%, for the beads that were prepared with 1 : 1 NaAlg/Gel at 16 days. The diffusion coefficients have been calculated for the transport of insecticide through the polymeric beads, using initial time approximation method. These values were also consistent with the carbaryl release data. The carbaryl release from most of the bead formulations followed the Fickian trend. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1310–1319, 2006     

聚苯乙烯-烯丙基硫脲/二氧化钛复合材料的制备及吸附性能的研究

以苯乙烯、丙烯基硫脲和纳米二氧化钛为原料,经聚合反应制备了聚苯乙烯-烯丙基硫脲/二氧化钛复合材料。采用红外光谱法、扫描电镜、X射线能谱法对其结构及元素组成进行了分析。以这种复合材料作为固相萃取填料,对重金属离子进行吸附试验,并以ICP-MS为检测手段,分别考察了流速和洗脱液对该填料吸附性能和回收率的影响。结果表明:这种复合材料对Ag+、Pb2+和Cr3+的吸附容量分别为13.51 mg/g、12.42 mg/g和5.30 mg/g,SPE/ICP-MS联用的这种方法的最低检出限分别为0.771、0.849和0.497μg/L。     

液相色谱-质谱联用法检测化妆品中添加的喹诺酮类药物

建立同时测定化妆品中的喹诺酮类抗生素(依诺沙星、氟罗沙星、氧氟沙星、诺氟沙星、培氟沙星、环丙沙星、恩诺沙星、沙拉沙星、双氟沙星、莫西沙星)的液相色谱-串联质谱法。方法样品以2%甲酸-乙腈(体积比15∶10)溶液超声提取,离心分离,以0.2%甲酸水-乙腈溶液为流动相,LCMS/MS测定喹诺酮类抗生素的含量。结果该方法的线性范围为1～50μg/g,相关系数>0.998,加标1～40μg/g时,回收率为84.3%～99.2%,RSD为0.5%～8.5%,检出限为0.1～0.2μg/kg。结论该方法灵敏、快速、准确,适用于化妆品中喹诺酮类抗生素的检测。