氯吡嘧磺隆高效液相色谱分析方法研究

本文采用液相色谱法,以乙腈和水为流动相,使用Promosil-C185μm填料的不锈钢柱和紫外检测器,在260nm波长下对氯吡嘧磺隆原药进行分离和定量分析。结果表明氯吡嘧磺隆的线性相关系数为0.999 8;标准偏差为0.23;变异系数为0.24%;平均回收率为99.93%。     

10%吡嘧磺隆可湿性粉剂的液相色谱分析

本文所述应用液相色谱法测定吡嘧磺隆可湿性粉剂有效成分含量的测定方法,此方法采用甲醇、水和冰乙酸为流动相,使用C18柱、紫外检测器的高效液相色谱,经验证其添加回收率为100.09%,标准偏差为0.133,变异系数为1.33%,线性方程相关系数为0.9997。本试验方法操作简便,分离效果好,响应时间短,是理想的分析方法。     

黑龙江省野慈姑对吡嘧磺隆的敏感性测定

采用盆栽法茎叶处理方式分别测定了黑龙江省五常市志广乡长富村（种群H-1）、兴凯湖农场一连队（种群H-2）、八五四农场现代农业研发中心（种群H-3）、鹤岗市江滨农场（种群H-4）、庆安县久胜镇久旺村（种群H-5）共5个地区水稻田野慈姑对吡嘧磺隆的ED50值。结果表明,不同种群对吡嘧磺隆的敏感性不同,敏感程度依次为：种群H-1>种群H-2>种群H-3>种群H-4>种群H-5,其ED50值(以有效成分计)分别为107.04、163.92、289.61、320.50、484.06 g /hm2。各种群对吡嘧磺隆的ED50值与其使用年限呈正相关,吡嘧磺隆使用年限越长的地区,野慈姑的ED50值越大;且各种群对吡嘧磺隆的ED50值是20世纪90年代初期黑龙江省水稻田吡嘧磺隆常规田间施药量(以有效成分计)10～15 g/hm2的10.7～48.4倍。     

嗪吡嘧磺隆33%水分散粒剂高效液相色谱分析方法研究

本文采用高效液相色谱法,以乙腈+磷酸溶液为流动相,使用以ZORBAX Extend-C18、5μm为填料的不锈钢柱和二极管阵列检测器,在240nm波长下对嗪吡嘧磺隆33%水分散粒剂进行分离和定量分析。结果表明,该分析方法的线性相关系数为0.999 9,标准偏差为0.09,变异系数为0.22%,平均回收率为99.99%。     

我国部分地区水稻田鳢肠对吡嘧磺隆的抗性测定

鳢肠Eclipta prostrata L.是我国水稻产区的主要恶性阔叶杂草之一,为了明确鳢肠对吡嘧磺隆的抗性发生情况,采用生物测定法检测了2011-2013年从山东省、湖北省和江苏省水稻田采集的28个鳢肠种群对吡嘧磺隆的抗性。结果表明,从山东省采集的7个种群、湖北省的17个种群和江苏省的3个种群均能被有效剂量30g/hm~2的吡嘧磺隆控制,表现为敏感;江苏省苏州市吴中区鳢肠种群LC12-25在30g/hm~2剂量下仍存活,进一步以江苏省敏感种群LC12-24为对照,对江苏省鳢肠种群LC12-25进行抗性水平测定。敏感种群LC12-24的GR50为0.25g/hm~2,抗性种群LC12-25的GR50为16.66g/hm~2,其抗药性指数(RI)达66.64,表明LC12-25种群对吡嘧磺隆产生了较高水平抗性。     

吡嘧磺隆在水稻直播田产生药害的原因及对策

文章叙述了10%吡嘧磺隆可湿性粉剂在水稻直播田使用产生药害的症状以及原因,提出了产生药害后的补救措施,同时对该药剂的基本使用方法和安全使用注意事项作了说明。     

黑龙江省稻田野慈姑对丙嗪嘧磺隆抗性相关研究

通过整株盆栽法研究黑龙江省佳木斯市汤原县(种群R1)、856农场(种群R2)、密山市(种群R3)3个水稻田野慈姑种群对丙嗪嘧磺隆的抗性水平,采用分子生物学技术分析3个野慈姑种群在靶标酶基因上的差异,确定3个野慈姑种群对丙嗪嘧磺隆和苄嘧磺隆是否存在交互抗性。结果显示,黑龙江R1、R2、R3种群抗性指数(RI)分别为11.92、22.68、35.99。与敏感的七台河种群S相比,R1、R2、R3的ALS基因均在Pro_(197)位发生不同突变。R1种群为Thr_(197)取代了Pro_(197);R2、R3种群为Ser_(197)取代了Pro_(197),ALS基因的突变是其产生抗性的主要原因。3个野慈姑种群对丙嗪嘧磺隆和苄嘧磺隆存在交互抗性。     

高效液相色谱-串联质谱检测水稻中氯吡嘧磺隆残留量

建立了高效液相色谱-串联质谱检测糙米、稻壳和秸秆中氯吡嘧磺隆残留的分析方法。样品经乙腈和水提取,C 18吸附剂净化,多反应监测模式检测,外标法定量。结果表明,在0.01~2mg/L范围内,氯吡嘧磺隆的质量浓度与对应的峰面积间呈良好的线性关系,其相关系数为0.9997。在0.01~0.5mg/kg添加水平下,氯吡嘧磺隆在糙米中的平均回收率为95%~98%,相对标准偏差(RSD)为2%~4%。在0.05~5mg/kg添加水平下,氯吡嘧磺隆在稻壳和秸秆中的平均回收率为78%~87%,相对标准偏差(RSD)为1%~5%。氯吡嘧磺隆在糙米中的定量限(LOQ)为0.01mg/kg,在稻壳和秸秆中的定量限(LOQ)为0.05mg/kg。该方法简便、快速、准确。     

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。     

Adsorption of glyphosate by soils

The adsorption of glyphosate in a slurry system by 9 soils was correlated with an arbitrary single point inorganic phosphate sorption index which gave a measure of unoccupied phosphate sorption capacity, but not with total phosphate sorption capacity at pH 2.6, the level of iron and aluminium soluble in Tamm's acid oxalate or with clay content, organic matter content or pH. It is concluded that inorganic phosphate excludes glyphosate from sorption sites. The extent of adsorption was higher than, though of the same order as, that of diuron though the two are not related. From consideration of the results of previous experiments with plants grown in culture solution it is suggested that the low phytotoxicity of glyphosate applied to the soil is not due simply to high adsorption. Rather it is the result of a combination of moderate adsorption and the low intrinsic activity of this compound when made available to the root system.     

三氟苯嘧啶在5种土壤中的吸附与解吸附行为

为研究三氟苯嘧啶的吸附-解吸附特性,采用振荡平衡法研究了三氟苯嘧啶在采集于吉林通化、江苏扬州、江西萍乡、广西南宁和海南海口等地的5种土壤中的吸附-解吸附行为及其环境影响因素。结果表明:三氟苯嘧啶在土壤中的吸附动力学符合Elovich模型,吸附和解吸附等温线符合Freundlich模型,吸附常数在1.886~7.626。温度的升高更有利于吸附,土壤对三氟苯嘧啶的吸附主要是物理吸附;随着溶液中pH值的升高,土壤对三氟苯嘧啶的吸附能力逐渐下降。除广西南宁黏壤土外,三氟苯嘧啶在5种土壤中的解吸附过程中存在滞后现象,不易在土壤中长期积累,具有一定的迁移特性。     

双氟磺草胺在不同类型土壤中的吸附与淋溶特性研究

农药在土壤中的吸附和淋溶特性是评价其环境行为的重要指标。采用批量平衡法和土柱淋溶法,研究了双氟磺草胺在小麦种植区3种代表性土壤中的吸附和淋溶特性。结果表明:双氟磺草胺在安徽黏土、山东砂质壤土和河南砂质黏壤土中的吸附规律均可以较好地用Freundlich方程描述,其吸附系数(Kf)在0.39~0.62之间;土壤有机碳归一化吸附系数(Koc)在66.91~81.35之间,表明双氟磺草胺在3种土壤中均属于难吸附型;吸附自由能(ΔG)在-10.90~-10.42kJ/mol之间,均属于物理吸附。双氟磺草胺在3种土壤中的淋出率在71.7%~74.1%之间,说明其在3种土壤中的淋溶性均较强。双氟磺草胺初始添加量和腐殖酸对淋出率具有一定影响。综合试验结果,认为双氟磺草胺在3种土壤中的吸附和淋溶可能受土壤有机质含量、黏粒含量、阳离子交换量和土壤pH值等多个因素的综合影响,其对地下水的污染风险较大,因此应引起高度重视。     

啶虫脒和阿维菌素在4种不同类型土壤中的吸附及迁移

采用薄层层析和平衡振荡法,分别测定了啶虫脒和阿维菌素在紫色土、砖红土、黄壤土和黑土4种不同类型土壤中的迁移率(Rf )和吸附常数(Kd),比较了2种农药在单用及混用下迁移和吸附行为的差异。结果表明:2种农药在单用及混用下的迁移行为几乎不存在差异,在4种土壤中的Rf 值大小顺序均为:黄壤土>紫色土>黑土>砖红土;2种农药的吸附过程均符合经典的Freundlich模型,混用时阿维菌素对啶虫脒的吸附无影响,但啶虫脒的存在会减少土壤对阿维菌素的吸附,表现为竞争吸附作用。     

Adsorption of ethofumesate by agricultural and natural soils

A study has been made of the effect of properties and composition of soils on the adsorption of ethofumesate. Adsorption isotherms of ethofumesate by agricultural and natural soils and by montmorillonite and humic acid were obtained. The correlations between the Freundlich K constants, and Kd distribution coefficients and the soil parameters were determined. Significant correlations (P<0.05) were found between K and clay content and between Kd and smectite content for the agricultural soils but the correlation with organic matter content was of borderline or no significance. Considering the agricultural and natural soils together or the soils with an organic matter content >2%, a highly significant correlation was found between K and the organic matter content. According to the r² determination coefficient, the organic matter content accounts for 88.4% of the variability in adsorption in the first case, and 92.2% in the second case. The log₁₀ Kd_om values of soils with an organic matter content >2% were similar and confirm the importance of the organic matter as a determinant parameter in the adsorption of ethofumesate by these soils. The adsorption of the herbicide by montmorillonite and humic acid confirmed the results obtained with the soils and point to the importance of the exchangeable cation nature of the samples and of the temperature in the adsorption process. Adsorption de l'éthofumesate dans des sols agri-coles et naturels L'effet des propriétés et de la composition du sol sur l'adsorption de l'ethofumesate a étéétudié. Les isothermes d'adsorption de 1'éthofumesate par des sols agricoles et naturels ainsi que par la montmorillonite et des acides humiques ont été déterminés. Les corrélations entre les caractéris-tiques du sol, les constantes de Freundlich K d'une part et les coefficients de distribution Kd d'autre part ont été déterminées. Des corrélations significatives (P<0.05) ont été mises en évidence entre K et la teneur en argile ainsi qu'entre Kd et la teneur en smectite pour les sols agricoles mais la correlation avec la teneur en matisre organique etait tout juste ou non significative. Lorsqu'on considérait les sols agricoles et naturels ensemble ou les sols dont la teneur en matière organique est supérieure à 2%, une corrélation hautement significative existait entre K et la teneur en matière organique. Le coefficient de détermination r² montre que la teneur en matière organique explique 88.4% de la vari-abilité de l'adsorption dans le premier cas et 92.2% dans le second cas. Le log₁₀ Kd_ométait similaire pour les sols de teneur en matière organique >2%, ce qui confirme l'importance du paramètre matière organique dans l'adsorption de 1'ethofumesate par ces sols. L'adsorption de I'herbicide par la montmorillonite et les acides humiques a confirmé les résultats obtenus avec les sols et a montre 1'importance de la température du process et de la nature des cations d'échange des échantillons. Adsorption von Ethofumesat in Acker- and natürlichen Böden Bei der Untersuchung der Wirkung der Eigen-schaften und der Zusammensetzung von Böden auf die Adsorption von Ethofumesat wurden Adsorplions-Isothermen mit Acker- und natürlichen Böden sowie mit Montmorillonit und Huminsäure ermittelt. Die Korrelationen zwischen den Freundlich-Konstanten K sowie den Verteilungskoeffizienten K_d und den Bodenparametern wurden bestimmt. Signifikante Korrelationen (P<0.05) wurden für K und den Tongehall und für K_d und den Smectit-Gehalt in Ackerböden gefunden, doch die Korrelation mit dem Gehalt an organischer Substanz war marginal oder nicht signifikant. Für Acker-und natürliche Böden insgesamt oder Böden mit einem Gehalt an organischer Substanz von >2% wurde eine hochsignifikante Korrelation zwischen K und dem C_org.-Gehalt gefunden. Das Bestimmtheitsmaß (r²) für die organische Substanz lag swischen 88.4% im ersten und 92.2% im zweiten Fall. Die log₁₀K_oc-Werte Böden mit einem C_org.-Gehalt von >2 % waren ähnlich und bestätigen die Bedeutung der organischen Substanz als bestimmenden Parameter für die Adsorption von Ethofumesat in diesen Böden. Die Adsorption des Herbizids an Montmorillonit und Huminsäure unterstreichen die an den Böden gewonnenen Ergebnisse und die Bedeutung der Kationen-Austauschfähigkeit der Proben.     

Behaviour of thiocarbamate herbicides in soils: Adsorption and volatilization

Adsorption and volatilization of cycloate, EPTC and vernolate applied to six types of soils were studied in the laboratory. Cycloate proved to be the most and EPTC the least adsorptive molecule in all systems examined, while the volatilization order of the compounds was the reverse EPTC>vernolate>cycloate. Neither the adsorption nor the volatilization of thiocarbamates was markedly affected by formulating agents. The adsorption isotherm of several systems did not obey the classical Freundlich equation. A reciprocal relationship which was found between the adsorption coefficients and the volatilization rates of thiocarbamates permits calculation of one of these properties if data on the other are available.     

鱼藤酮在3种土壤中的吸附-解吸附特性

为了综合评价鱼藤酮在土壤环境中的吸附-解吸附特性,采用批量平衡法,系统研究了鱼藤酮在砂壤土、黏壤土及壤土3种农业土壤中的吸附-解吸附行为。结果表明,鱼藤酮在3种土壤中的吸附-解吸附行为符合Freundlich模型 (R2≥0.946 8),吸附常数 (K_f-ads) 在1.52~11.39之间,吸附能力为:黏壤土 > 砂壤土 > 壤土;而解吸附常数 (K_f-des) 在1.02~4.55之间,解吸附强弱次序为壤土 > 黏壤土 > 砂壤土。鱼藤酮在砂壤土、黏壤土和壤土3种土壤中有机碳吸附常数 (K_OC) 分别为982、101 7和219,而滞后系数 (H) 分别为0.687 3、0.556 9和0.892 3,表明鱼藤酮在黏壤土及砂壤土中移动性较弱,有正迟滞作用,而在壤土中移动性较强,无迟滞作用。该研究将对鱼藤酮的环境风险评估具有一定的理论指导意义。     

七种农药在3种不同类型土壤中的吸附及淋溶特性

采用振荡平衡法和土柱淋溶法研究了2,4-滴酸、丁噻隆、毒草胺、炔草酸、氟环唑、甲基磺草酮和烯啶虫胺7种农药在江西红壤、太湖水稻土及东北黑土3种不同理化性质土壤中的吸附及淋溶特性,探讨了农药性质及土壤理化性质对供试农药在土壤中吸附、淋溶行为的影响。结果表明:农药的水溶性越大,其在土壤中的吸附性越弱,淋溶性越强;农药在土壤中的吸附性与土壤pH值、有机质含量以及阳离子交换量之间有较好的相关性。土壤pH值、有机质含量以及农药性质是影响农药在土壤中淋溶及迁移的主要因素。     

Measurement and simulation of herbicide transport in macroporous soils

Lysimeter experiments were carried out to study pesticide transport through macroporous soils. In order to differentiate between the effects of soil structure and chemical behaviour, the leaching experiments were conducted using disturbed and undisturbed soil samples. Two herbicides with different sorption behaviours, and bromide as tracer were applied. The results were used to validate a dynamic simulation model which considers bypass flow in macropores. The simulation results show that the model is able to reproduce the soil suction within the soil as well as the spatial distribution of bromide and the herbicides. The continuity of the macropores is most important for the efficiency of bypass flow. The results indicate that cultivation practices like ploughing significantly influence the temporal and spatial distribution of the macropores. © 1998 SCI.     

Adsorption,desorption and dissipation of metolachlor in surface and subsurface soils

BACKGROUND: Variations in soil properties with depth influence retention and degradation of pesticides. Understanding how soil properties within a profile affect pesticide retention and degradation will result in more accurate prediction by simulation models of pesticide fate and potential groundwater contamination. Metolachlor is more persistent than other acetanilide herbicides in the soil environment and has the potential to leach into groundwater. Reasonably, information is needed about the dissipation and eventual fate of metolachlor in subsoils. The objectives were to evaluate the adsorption and desorption characteristics and to determine the dissipation rates of metolachlor in both surface and subsurface soil samples. RESULTS: Adsorption of metolachlor was greater in the high‐organic‐matter surface soil than in subsoils. Lower adsorption distribution coefficient (K_ads) values with increasing depth indicated less adsorption at lower depths and greater leaching potential of metolachlor after passage through the surface horizon. Desorption of metolachlor showed hysteresis, indicated by the higher adsorption slope (1/n_ads) compared with the desorption slope (1/n_des). Soils that adsorbed more metolachlor also desorbed less metolachlor. Metolachlor dissipation rates generally decreased with increasing soil depth. The first‐order dissipation rate was highest at the 0–50 cm depth (0.140 week^?1) and lowest at the 350–425 cm depth (0.005 week^?1). Degradation of the herbicide was significantly correlated with microbial activity in soils. CONCLUSION: Metolachlor that has escaped degradation or binding to organic matter at the soil surface might leach into the subsurface soil where it will dissipate slowly and be subject to transport to groundwater. Copyright © 2009 Society of Chemical Industry