水果中多菌灵农药残留检测方法的比较与基质效应研究

对分散固相萃取-高效液相色谱法检测6种水果中多菌灵农药残留的应用进行了评价,获得农药浓度在0.01~3.0 mg/kg范围内呈良好的线性关系,线性相关系数在0.999以上,平均回收率在88%~104.7%范围,方法的RSD值小于5%。方法的准确度和精密度都满足要求。并将其与国内外现行的4种多菌灵标准检测方法进行比较,发现并分析了试验中出现的基体效应,指出了分散固相萃取-高效液相色谱法在检测分析多菌灵农药残留的优势。     

气相色谱-质谱法测定蔬菜与水果中11种三唑类农药残留

建立了蔬菜和水果中11种三唑类农药残留的气相色谱-质谱(GC - MS)测定方法.样品用乙腈均质提取,经石墨化炭黑/氨基复合柱净化,乙腈-甲苯(3:1)洗脱.洗脱液经浓缩、溶剂交换后定容,采用气相色谱-质谱的选择离子监测方式( GC - MSD/SIM)进行测定,内标法定量.方法的线性范围为0.05～5 ng,相关系数...     

飞行时间质谱技术在水果、蔬菜与茶叶中农药残留分析中的应用

飞行时间质谱(TOF-MS)是一种速度快、范围广、灵敏度高、分辨率高的质谱技术,相对于常规离子阱、四极杆质谱仪,具有定性能力更强、通量筛查能力更高的优点,TOF-MS技术的不断改进,为科研工作者提供了更好的研究手段,其在农产品质量安全农药残留定性定量筛查分析中也日益受到青睐。该文针对2010年来国内外期刊上发表的TOF-MS技术在水果、蔬菜和茶叶中农药残留分析上的应用文献,从TOF-MS与气相色谱、液相色谱和合相色谱联用3个方面上的应用出发,进行综述分析,并对该技术在水果、蔬菜和茶叶农药残留分析上的发展前景进行了展望。     

农村化学教学现状的调查

近两年来,笔者在有关教师和领导的帮助下,对我县33所农村中学进行了全面的化学教学现状调查,调查的目的是了解当前农村化学教学中存在的问题,为教育改革提供一些依据。调查的对象主要是化学教师和学生,通过听课、查阅有关材料、观察、座谈、问卷、抽试等形式,深入学校、深入课堂,两年来共听课165节,问卷12次,抽试25场次,召开座谈会16场次,检查了各校。     

不同基质中有机氯农药提取技术及发展趋势

该文根据各种基质特点及其中有机氯农药的分布特点,对不同介质中有机氯农药的提取方法进行了归纳.着重介绍了不同基质中有机氯农药提取方法,如均质法、固相萃取法、索氏提取法、基质固相分散法、加速溶剂萃取法、超临界流体提取法、超声波提取法和微波辅助提取法等.通过详细实例,总结了上述提取方法的优缺点,并对有机氯农药提取方法做了展望...     

7313、7321系列农药的构效关系研究

对7313、7321系列农药利用MOPAC程序包PM3方法进行量子化学计算,讨论了它们的活性部位及构效关系,发现形成6员稠合环结构有利于分子产生药效,N(7)、S(9)、N(11)、C(12)等原子分别与受体的自由基相作用,是该类农药产生共同生物活性的化学基础。     

Pesticides Identification and Sustainable Viticulture Practices to Reduce Their Use: An Overview

The use of pesticides is a necessary practice in the modern era. Therefore, it is impossible to ignore the pesticide market, which has developed into one of the most lucrative in the world. Nowadays, humans are subjected to many potential risks, and significant amounts of toxic compounds enter their bodies through food, drink, and the air itself. Identification and quantification of these hazardous compounds is crucial for the sustainable development of an increasing world population which poses high climatic and political constraints on agricultural production systems. The maximum residue limits for pesticides have been regulated by the Codex Alimentarius Commission and European Union to protect human health. In this review, we have summarized and explained the analytical methods for pesticide extraction and determination. Also, sustainable viticulture practices like organic vineyards, tillage, biopesticides, nanobiopesticides, and precision viticulture are briefly discussed. These new techniques allow wine growers to be more profitable and efficient, while contributing to the reduction of pests and increasing the quality of wines.     

Field Desorption Mass Spectrometry of Standard Organophosphorus Pesticides and Their Identification in Waste Water

The characteristic behaviour of four groups of commonly used organophosphorus pesticides such as phosphates, phosphorothionates, phosphorothiolates and phosphorodithioates has been investigated by field desorption mass spectrometry. Their spectra show molecular ions of high abundance and characteristic fragmentation patterns. The phosphates and phosphorothionates usually show the α-cleavage with respect to the P-atom with and without proton transfer. In contrast, the phosphorothiolates and phosphorodithioates usually show the β-cleavage from the P-atom. The fragments with the charge retention on the phosphorus moiety were also observed in the field desorption mass spectra, although their abundances were often relatively low.

The analyses of standard mixtures as well as some waste water samples indicate that field desorption mass spectrometry is suitable for the identification of organophosphorus pesticides at nanogram level in mixtures and environmental samples without preliminary separation and purification.     

苹果中5种氨基甲酸酯类农药的超临界流体萃取及其气相色谱法测定

提出了一种采用超临界流体萃取技术对苹果中５种氨基甲酸酯类农药进行萃取及用气相色谱检测的方法。实验以二氧化碳作为超临界流体，加入３％的甲醇作为改性剂，对３种惰性载体和加入硅藻土的苹果基体的超临界萃取条件进行了选择，以气相色谱配以氮磷检测器检测５种氨基甲酸酯类农药，取得了满意的结果，回收率为８８％～９８％。     

A Distribution Chromatography Method for the Identification of Pesticides in Their Mixtures and Agricultural Products

The distribution of 166 pesticides of various classes (amides, dinitroanilines, pyrethroids, thiocarbamates, triazines, etc.) was studied at 20 ± 1°C in multiple extraction systems. The distribution constants (P) of pesticides between hexane and a polar phase are calculated. Based on the distribution constants of pesticides, a possibility of using distribution chromatography for their identification was considered. It is demonstrated on an example of pesticides with similar retention times that the hexane–water extraction system is most selective and universal for the identification of most compounds by gas and liquid chromatography. Using this system, logarithms of distribution constants of the substances under consideration are maximally differentiated and ranged from–1.32 to 8.0. Such a range makes it possible, with an acceptable volume ratio of the hexane and water phases (up to 1: 500), to achieve a significant decrease in the peak area of the pesticide in hexane when it is washed with water in accordance with its P value up to logP = 3.0. In the case of more hydrophobic pesticides, extraction systems of hexane–ethylene glycol, hexane–acetonitrile, and hexane–mixtures of acetonitrile with water and ethylene glycol can be used.     

20种农药的标准Kováts指数及其在程序升温下的活数据库定性

在标准的交联SE-54毛细管上,准确地测量了20种农药的Kovats指数及温度系数,用以扩充Sadtler标准库。所测农药Kovats指数的温度系数在0.2～1.8指数单位/℃,显示出强极性和高活性,为克服Sadtler标准库对色谱柱和操作条件的苛刻要求,我们试用了保留值活数据库(简称LRD)方法.在程序升温条件下对农药定性。LRD用标准Kovats指数及其温度系数作为基础数据,替代标准样。在不同的程序升温条件下,对农药的实测与LRD计算保留值进行了比较。结果表明,对农药类特殊样品,保留时间的计算精度≤±1％,这证明在程序升温条件下,可用LRD方法对农药分析定性。     

新型绿色农药——光活化农药

光活化农药包括光活化杀虫剂和光活化除草剂, 与传统农药相比具有廉价、高效、无污染等优越性。光活化农药的关键是光敏剂, 在有光和氧存在条件下光敏剂催化产生单重态氧, 杀灭害虫。光敏剂效果取决于其单重态氧的量子产率, 其分子本身只起催化作用并不介入毒性反应, 并且易被降解, 因此对环境无污染。由于单重态氧在细胞上的生物化学作用点多, 使害虫不易对其产生抗药性。这类绿色农药正在逐步走向实用化, 它的发展将会大大改善因长期使用传统农药而造成的危害, 对农业发展将会产生巨大的促进作用。     

农药的危害与微生物农药的开发

农药与人类的健康和农业生态平衡的被破坏有密切关系，人们往往把“农药”视为“毒药”。本文介绍常用农药对人类的健康和环境造成的危害；大力开发和使用微生物农药，逐步消除农药产生的公害问题，并纠正人们对农药的片面认识。