斜投影-子空间夹角算法快速分析农药中阿维菌素

采用斜投影-子空间夹角算法快速分析农药中阿维菌素的含量。用斜投影算法从阿维菌素对照品中提取阿维菌素B_(1a)纯光谱数据,用子空间夹角判据计算农药中阿维菌素的含量。阿维菌素的质量浓度在4~14μg/mL范围内与用斜投影法提取的阿维菌素B_(1a)纯光谱吸光度呈良好的线性关系,相关系数r=0.9994。斜投影-子空间夹角算法加标回收率在98.80%~101.67%之间,测定结果的相对标准偏差小于2%(n=6)。用该方法与高效液相色谱法对同一样品进行测定,两种方法测定结果相接近,相对误差小于2.20%。该方法满足快速检测农药中阿维菌素含量的分析要求。     

Nutraceutical Products—State-of-the-Art for Sample Preparation in Pesticide Residues Analysis

Nutraceutical products are plant-based materials primarily valued for their possible medicinal or therapeutic properties. According to their “natural” origin they are often perceived as being safe; however, for the prevention of economic losses, pesticides may be used against pest, mold and insects causing plant damage. Bearing in mind that a nutraceutical is a concentrated form of the plant, pesticides could be found in the final product in possibly worrying concentration. Nutraceutical products and dried herb materials typically represent very complex matrices for pesticide residue analysis, therefore a proper sample preparation protocol with appropriate clean-up steps is necessary prior to the analysis. Hence, this article gives an overview of pesticide residue analyses in nutraceuticals and provides the state of the art for sample preparation techniques applied for different types of nutraceuticals.     

Organophosphorus and carbamate pesticide analysis using an inhibition tyrosinase organic phase enzyme sensor; comparison by butyrylcholinesterase+choline oxidase opee and application to natural waters

Recent research performed in our laboratory (using a butyrylcholinesterase + choline oxidase enzyme electrode) suggested the validity of the biosensor approach using enzyme inhibition OPEEs (i.e. enzyme electrodes working in organic phase) in the case of organophosphorus and carbamate pesticides, which are poorly soluble in aqueous solutions. Since these pesticides are generally much more soluble in chloroform than in water, the present research aimed at analysing this class of pesticides using a tyrosinase inhibition OPEE operating in water-saturated chloroform medium. The tyrosinase biosensor was assembled using an oxygen amperometric transducer coupled to the tyrosinase enzyme, immobilized in kappa-carrageenan gel. Lastly a detailed comparison between the inhibition monoenzymatic tyrosinase and inhibition bienzymatic (butyrylcholinesterase + choline oxidase) OPEEs was performed and discussed in this work.     

Cholinesterase-based dipstick assay for the detection of organophosphate and carbamate pesticides

A cholinesterase (ChE)-based dipstick-type assay for the class-specific detection of organophosphate (OP) and carbamate (CM) pesticides was developed. The principle of the assay is based on inhibition of the activity of a ChE by these two families of pesticides, which is dependent on the concentration of pesticides. The proposed assay system is composed of a test strip with an acetylcholinesterase (AChE)-coated membrane and an enzyme substrate solution. The assay protocol involves incubation of the enzyme-coated strip in the pesticide-containing sample solution followed by incubation of the sample-treated strip in a chromogenic enzyme substrate solution. The color intensity is estimated by the naked eye or a reflectometer. Of the membranes tested as the enzyme support, Hybond N⁺ was the most suitable. Among the compounds tested as the enzyme substrate, indophenyl acetate was the best. The detectable concentration range of the dipstick assay for the OP and CM pesticides was 10⁻⁶-10² and 10⁻⁶-10⁰ μg mL⁻¹, respectively. The sensitivity of the dipstick assay to the oxidized form of parathion (paraoxon) was higher than to parathion. The strip showed a large matrix effect with pesticide-spiked lettuce samples, whereas it showed a small matrix effect with pesticide-spiked rice samples.     

农药化学现状和发展动向

本文介绍农药化学现状,并与医药化学的研究特点进行比较。近年农药研究比较活跃的领域有天然农药、原农药、手性农药等。在新农药创制中发展较快的有超高效农药、特异性农药(生物调节剂),元素有机农药和复配农药,最后对农药化学展望作一概述。     

微波萃取技术

介绍了在气相／液相色谱测定前的一种新的样品制备技术——微波萃取技术及其所使用的试剂、设备和条件。通过一些数据以及与Ｓｏｘｈｌｅｔ法、超声萃取法比较说明,微波萃取是一种快速、试剂用量少、回收率高、灵敏以及易于自动控制的方法。     

高效液相色谱法测定西红柿中克线磷残留量

高效液相色谱法测定西红柿中克线磷残留量包宏,夏民洲,胡兹苓（南京林业大学南京２１００３７）１前言克线磷（ｆｅｎａｍｉｐｈｏｓ）,商品名Ｎｅｍａｃｕｒ,是防治作物根结、孢囊与自由线虫的杀线虫农药￣［１］。对它的残留分析,有气相色谱法和薄层色谱法等￣［２...     

杀螨王及其代谢物残留总量的气相色谱分析法

报道了杀螨王（fenpyroximate）及其代谢物顺式体在HCl-H2SO4混合液中定量分解为可经气相色谱分析的1,3-二甲基-5-苯氧基吡唑-4-醛,建立了苹果、柑桔和土壤样品中残留总量的气相色谱分析法。添加浓度0.05～1.0mg/kg,苹果、桔皮、桔肉和土壤样品中杀螨王总量平均回收率分别为104.7～124.8%,90.9～93.8%,89.3～94.0%和104.3～113.0%,变异系数依次为3.3～11.8%,2.7～7.5%,1.4～2.7%和1.5～4.0%。     

Direct chiral high performance liquid chromatography separation of O-ethyl O-phenylN - isopropylphosphoroamidothioates

The enantiomers of thirty-nine O-ethyl O-phenyl N-isopropyl phosphoroamidothioates have been separated by high performance liquid chromatography on a Pirkle model chiral stationary phase using ten mobile phase. Chromatographic data are presented for the separation of these organic phosphorus enantiomers on the chiral phase. The influences of molecular structures and compositions of mobile phases have been described.     

沙蚕毒系仿生性农药(CH3)2NHCH(CH2S2O3)2NaH2O的电化学研究

杀虫单（ＣＨ３）２ＮＨＣＨ（ＣＨ２Ｓ２Ｏ３）２Ｎａ·Ｈ２Ｏ是我国独自开发的一种沙蚕毒系仿生性农药．我们用循环伏安法和计时库仑法研究了杀虫单的电极反应过程及在电位扫描速率,支持电解质ＰＨ以及浓度变化时对峰电流及峰电位的影响．研究表明杀虫单发生不可逆还原电极反应,还原产物二氢沙蚕毒素在电极上发生强吸附,其吸附量为８．２３×１０－１０ｍｏｌ／ｃｍ２．在随后的循环电位扫描中二氢沙蚕毒素氧化生成沙蚕毒素在循环伏安图上出现新电流峰．沙蚕毒素与二氢沙蚕素的峰电位相差３３ｍＶ,两者间有２电子可逆电极反应特征