Voltammetric determination of mesotrione at hanging mercury drop electrode

A study of the electrochemical reduction of the mesotrione pesticide on a hanging mercury drop electrode (HMDE) was performed as a basis for the development of a sensitive analytical method for natural samples. The electrochemical characteristics of herbicide mesotrione dissolved in a phosphate buffer (pH 7.0) have been determined by means of electrochemical techniques such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV) over a wide range of pH from 2.0 to 10.0. The experimental parameters, such as electrolyte type and its pH, pulse amplitude, and scan rate were optimized. The method was applied to the determination of the pesticide in a spiked soil samples. Using this method, a linear calibration curve for mesotrione was obtained up to the 0.1 μM range in pH 7 phosphate buffer solution with a detection limit (S/N = 3) of 50 nM. The method can be applied successfully to the determination of mesotrione in soils. The text was submitted by the authors in English.     

超高效液相色谱-串联质谱法测定玉米中硝磺草酮及其代谢物残留量

建立了超高效液相色谱-串联质谱法测定玉米中硝磺草酮及其代谢物(MNBA)的残留分析方法。样品用乙腈-水溶液提取,取适量提取液用甲酸酸化至pH 2,过HLB固相萃取柱进行净化,用甲醇-乙醚(70∶30,V/V)洗脱,洗脱液用氮气吹至近干,用1 mmol/L醋酸铵-乙腈(25∶75,V/V)定容后进行质谱分析,利用基质校正曲线对其准确定量。硝磺草酮和MNBA在1～200μg/L浓度范围内呈线性关系,相关系数均大于0.99,在添加浓度5～50μg/kg范围内,硝磺草酮及其代谢物MNBA的平均回收率为83.8%～101.1%,相对标准偏差在5.3%～12.8%之间,硝磺草酮和代谢物MNBA定量限分别为1.0和2.0μg/kg。     

反相高效液相色谱法测定水中的甲基磺草酮农药

建立了二氯甲烷萃取浓缩,反相高效液相色谱测定水样中甲基磺草酮农药含量的分析方法.调节水样pH值为4.0后,以二氯甲烷为萃取剂,25℃下重复萃取两次,萃取时间为15min,旋转蒸发仪浓缩近干,乙腈定容.以SPHERI-5RP-18 （5μm）为色谱柱,乙腈-磷酸缓冲溶液（pH值4.0）为流动相,紫外检测波长为220nm.结果表明,在选定的萃取和色谱条件下,甲基磺草酮测定的线性范围为0.5-100.0mg/L,线性相关系数r为0.9996,标准偏差（SD）为0.46,变异系数（CV）为0.47％,平均加标回收率88.9％,检出限为0.03mg/L.此方法可用于实际水样中甲基磺草酮农药含量的测定.     

高效液相色谱-串联质谱法测定食品中硝磺草酮

1 引 言 硝磺草酮(Mesotrione),化学名2-(4-甲磺酰基2硝基苯甲酰基)环己烷1,3二酮,又名甲基磺草酮、硝磺酮,是瑞士先正达公司发明的玉米田芽前和苗后广谱选择性除草剂,因具有低毒性、高活性、对环境友好等特点[1,2],是近几年广泛使用的除草剂.但最近研究发现,硝磺草酮具有高效的起始活性和残留活性,长期食用含有硝磺草酮残留的食物会对人畜产生致癌作用,或引起胎儿畸形[3,4].欧盟和世界贸易组织对浆果、亚麻籽、越橘、栗草料等物质中硝磺草酮的限量为0.05 mg/kg.而美国、加拿大等国对芦笋、草杆、草料等物质中硝磺草酮的限量为0.01 mg/kg[10-13].     

液相色谱-串联质谱法测定食品中甲基磺草酮

食品用乙腈-水(3+1)溶液进行提取,经凝胶色谱、固相萃取柱净化后,用液相色谱-串联质谱法进行测定和确证,外标法定量。色谱分离用甲醇和甲酸-水(0.1+99.9)溶液以不同体积比混合为流动相梯度洗脱,采用负离子模式电喷雾离子源在多反应监测模式下进行检测。甲基磺草酮的质量浓度在0.01~0.2 mg·L-1范围内与其峰面积呈线性关系。以4种食品样品为基体,加入3种浓度水平的甲基磺草酮标准做回收试验,测得回收率在73.2%~100.6%之间;测定值的相对标准偏差(n=10)在4.1%~11%之间。     

Sonochemical construction of hierarchical strontium doped lanthanum trisulfide electrocatalyst: An efficient electrode for highly sensitive detection of ecological pollutant in food and water

Herbicides are used constantly in agriculture to enhance productivity across the globe. This herbicide monitoring requires utmost importance since its high dose leads to ecological imbalance and a negative impact on the environment. Moreover, a quantification of toxic herbicide is one of the important problems in the food analysis. In this work, deals with the development of a simple, and facile one-pot sonochemical synthesis of strontium doped La₂S₃ (Sr@La₂S₃). Morphological and structural characterization confirms the doping of Sr@La₂S₃ to generate a hierarchical layered structure. The electrochemical performance of modified with rotating disk electrode (RDE) using Sr@La₂S₃ composite is high, compared to La₂S₃ and bare electrodes towards the quantitative detection of mesotrione (MTO) in phosphate buffer. Sr@La₂S₃/RDE showed good sensitivity for MTO detection and it exhibit a range of 0.01–307.01 μM and limit of detection of 2.4 nM. Besides, the selectivity of fabricated electrode is high as it can electrochemically reduce MTO particularly, even in the presence of other chemicals, biological molecules and inorganic ions. The repeatability of MTO detection is high even after 30 days with a lower RSD values. Hence, simple fabrication of Sr@La₂S₃/RDE could be a novel electrode for the sensitive, selective, and reproducible determination of herbicides in real-time applications.