Characterization of triadimefon sorption in soils using supercritical fluid (SFE) and accelerated solvent (ASE) extraction techniques

Sorption–desorption of the fungicide triadimefon in field‐moist silt loam and sandy loam soils were determined using low‐density supercritical fluid extraction (SFE). The selectivity of SFE enables extraction of triadimefon from the soil water phase only, thus allowing calculation of sorption coefficients (K_d) at field‐moist or unsaturated conditions. Triadimefon sorption was influenced by factors such as soil moisture content and temperature; sorption increased with increased moisture content up to saturation, and decreased with increased temperature. For instance, K_d values for triadimefon on the silt loam and the sandy loam soils at 40 °C and 10% water content were 1.9 and 2.5 ml g⁻¹, respectively, and at 18% water content, 3.3 and 6.4 ml g⁻¹, respectively. Isosteric heats of sorption (ΔH_i) were −42 and −7 kJ mol⁻¹ for the silt loam and sandy loam soils, respectively. Sorption–desorption was also determined using an automated accelerated solvent extraction system (ASE), in which triadimefon was extracted from silt loam soil by 0.01 M CaCl₂. Using the ASE system, which is basically a fast alternative to the batch equilibration system, gave a similar ΔH_i value (−29 kJ mol⁻¹) for the silt loam soil (K_f = 27 µg^{1 − 1/n} ml^1/n g⁻¹). In order to predict transport of pesticides through the soil profile more accurately on the basis of these data, information is needed on sorption as a function of soil water content. © 2000 Society of Chemical Industry     

超临界流体提取技术与农药残留分析

本文介绍超临界流体提取技术在农药残留分析中的应用，超临界流体提取技术的主要优点是取时间短，耗费有机溶剂少和提取条件可控制，它克服了溶剂提取的缺点，提取效果接近索氏法，已经成为一种优秀的样品制备技术，农药残留分析中采用这一技术具有很有价值的。     

超临界萃取技术在农药残留分析中的应用研究进展

从超临界流体萃取的原理和特点、提取剂种类、样品前处理、萃取条件的选择、超临界萃取与3种经典提取方法的比较等5个方面进行了综述,并展望了其应用前景,旨在使国内对这项技术在农药残留上的应用引起重视。     

基于SFE-GC/MS技术的敌敌畏在柳树中的传导与分布

建立了一种利用超临界CO2萃取-气质联用(SFE-GC/MS)技术测定树干注药后柳树中敌敌畏残留量的分析方法。超临界CO2萃取柳树组织中敌敌畏的适宜条件为:温度40℃、压力34.48MPa、静态萃取时间20min、动态萃取CO2体积为20ml(1.0ml/min)、夹带剂甲醇(添加量0.15ml/g)、收集液丙酮。通过上述方法对柳树体内各组织中敌敌畏含量动态变化测定结果表明:敌敌畏经树干注药可在柳树体内经木质部长距离传导,分布于树体各组织中。树干注药后不同时间,敌敌畏在柳树树冠内不同部位的传导、分布存在较大差异。药剂进入木质部后,首先沿注药孔上方输导组织随蒸腾流纵向传导,进入注药孔上方的叶片中。树干注药24h时,树体各部位叶片内药剂含量差异最大,随着时间的延长,药剂在树体内逐渐降解,含量逐渐降低,各部位叶片内药剂含量差异也逐渐缩小,96h后在树冠各部位趋于均衡分布。树干注药初期叶片内药剂含量大于树体其他部位,随时间的延长,含量逐渐下降。注药7d后,药剂在树体各部位趋于均匀分布。     

几种分离技术在农药残留分析中的应用

本文介绍了样品现代前处理技术加速溶剂萃取(ASE)、超临界流体萃取(SFE)、固相萃取(SPE)、固相微萃取(SPME)、凝胶渗透色谱(GPC)的原理及其在农药残留分析中应用情况。     

基于SFE-GC/MS技术的敌敌畏在柳树中的传导与分布

建立了一种利用超临界CO2萃取-气质联用(SFE-GC/MS)技术测定树干注药后柳树中敌敌畏残留量的分析方法。超临界CO2萃取柳树组织中敌敌畏的适宜条件为:温度40℃、压力34.48MPa、静态萃取时间20min、动态萃取CO2体积为20ml(1.0ml/min)、夹带剂甲醇(添加量0.15ml/g)、收集液丙酮。通过上述方法对柳树体内各组织中敌敌畏含量动态变化测定结果表明:敌敌畏经树干注药可在柳树体内经木质部长距离传导,分布于树体各组织中。树干注药后不同时间,敌敌畏在柳树树冠内不同部位的传导、分布存在较大差异。药剂进入木质部后,首先沿注药孔上方输导组织随蒸腾流纵向传导,进入注药孔上方的叶片中。树干注药24h时,树体各部位叶片内药剂含量差异最大,随着时间的延长,药剂在树体内逐渐降解,含量逐渐降低,各部位叶片内药剂含量差异也逐渐缩小,96h后在树冠各部位趋于均衡分布。树干注药初期叶片内药剂含量大于树体其他部位,随时间的延长,含量逐渐下降。注药7d后,药剂在树体各部位趋于均匀分布。     

The determination of abamectin from soil and animal tissue by supercritical fluid extraction and fluorescence detection

The insecticide abamectin is extracted from soil and animal tissue by supercritical fluid extraction. Supercritical carbon dioxide modified with 9% 2-methoxyethanol extracted abamectin from soil samples at levels up to 11 ng g^?1 with greater than 80% efficiency. Recovery at fortification levels of 5 ng g^?1 were obtainable without the need for clean-up. Abamectin was also easily extracted from animal tissue at levels of 22ng g^?1 without interfering coextractives. Extracted abamectin was determined by liquid chromatography of a fluorescent derivative.     

蔗糖脂肪酸酯对大豆叶片超氧化物歧化酶和叶绿素的影响

本文研究了蔗糖脂肪酸酯（ＳＦＥ）对开花期和结英期大豆叶片中超氧化物歧化酶（ＳＯＤ）、叶绿素含量和大豆产量的影响。实验结果表明,在大豆开花期和结英期两个时期都喷施０．１％的ＳＦＥ后,可以使ＳＯＤ酶的相对活力提高４１％、叶绿素ｂ的含量提高５８％左右,并在处理后４～５天叶绿素含量提高;ＳＦＥ能增加叶片中的含氮量２倍左右,增加植株的单株结英数７０％和种子的百粒重３２％,并能提高种子中的蛋白质含量４．８％。     

紫茎泽兰化学成分的分离鉴定及抑菌活性测定

对紫茎泽兰全株进行分离鉴定,得到14个化合物,其化学结构分别确定为:3β-20(29)-烯基-3-羽扇豆醇硬脂酸酯(Ⅰ)、达玛烷-20,24-双烯-3α-乙酸酯(Ⅱ)、十七烷酸甲酯(Ⅲ)、(1S*,6R*,7R*,10R*)-杜松-4-烯-7-醇(Ⅳ)、表木栓醇(Ⅴ)、2-脱氧-2乙酰氧基-9-羰基泽兰酮(Ⅵ)、正二十三烷醇(Ⅶ)、豆甾醇(Ⅷ)、2,2′-(1,4-二萘基)双(苯并恶唑)(Ⅸ)、7-羰基泽兰酮(Ⅹ)、阿魏酸(Ⅺ)、蒲公英甾醇棕榈酸酯(Ⅻ)、(-)-(5S*,6S*,7S*,9R*,10S*)-7-hydroxy-5,7-epidioxycadinan-3-ene-2-one(ⅩⅢ)、邻羟基桂皮酸(ⅩⅣ),其中化合物Ⅰ、Ⅳ、Ⅸ为首次从紫茎泽兰中分离得到。采用孢子萌发法对部分化合物进行了抑菌试验,结果表明化合物Ⅰ对霜疫霉有较好的抑制作用,EC50值为86.9μg/mL。     

两种药剂在杨树体内分布动态的超临界流体萃取技术研究

建立了一种利用离线超临界CO2萃取气相色谱(SFE-GC)测定杨树体内中氧化乐果和敌敌畏分布动态的分析方法。超临界CO2萃取杨树体内氧化乐果和敌敌畏的适宜条件为:温度80℃、压力34.48MPa、调节剂甲醇(添加量0.70ml/g)、收集液丙酮、静态萃取时间25min、CO2流量为1ml/min、动态萃取18min。敌敌畏添加回收率为83.87%￣101.91%,相对标准偏差(RSD)为1.19%￣18.52%,氧化乐果添加回收率为75.34%￣95.43%,相对标准偏差(RSD)为3.72%￣14.14%,符合残留分析要求。整个分析时间小于3h。