计算机辅助对农药杀虫剂质谱信息的分类预测

对农药质谱信息的研究有助于辅助完成农药残留的鉴别和农药前体化合物的筛选。根据GB 4839-1998,选出4类杀虫剂,其常见化学结构有有机氯类、有机磷类、氨基甲酸酯类和拟除虫菊酯类农药。从NIST2.0质谱数据库中提取针对这4类结构的质谱数据,经过数学变换以及遗传算法和偏最小二乘回归相结合(GA-PLS)特征选择后,确定最优的质谱特征集,最后使用K最邻近法(KNN),支持向量机(SVM),助推法与分类回归树(AdaBoost-CART)构建预测模型。实验表明,SVM和AdaBoost-CART使用仅含有少量的特征组成的最优特征集,可以得到较好的预测结果。     

Rapid determination of aniline metabolites of chlorpropham in potatoes by micellar electrokinetic chromatography using negative-charged mixed micelles and laser-induced fluorescence detection

A rapid, reliable method has been developed for the multi-residue analysis of aniline metabolites of chlorpropham in potato samples. The method involves the precolumn derivatization of aniline metabolites with 5-(4,6-dichloro-s-triazin-2-ylamino) fluorescein (DTAF) and their subsequent separation and determination by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection (MEKC-LIF). The optimum procedure includes a derivatization step of the aniline metabolites (3-chloroaniline, 3-chloro-4-hydroxyaniline and 3-chloro-4-methoxyaniline) at 40 degrees C for 40 min and a 5-fold dilution prior to MEKC analysis, which is conducted within about 7 min using negative-charged mixed micelles (SDS/Triton X-100) in the running buffer. Under these conditions, the DTAF-anilines were readily detected at 0.3-3.1 microg/L level with a precision of 4.8-6.4%. These results indicate that negative-charged mixed surfactant MEKC-LIF is useful as a selective, rapid, and sensitive tool for the determination of these anilines and surpasses other electrophoretic alternatives based on the use of fluorescein-isothiocyanate (FITC) as label reagent. Finally, the potato matrix showed no significant effects on the derivatization and determination of these analytes, since the analytical figures of merit for the real samples were similar to those obtained in aqueous solutions, and the average recovery at fortification levels of 10-250 microg/kg was over 97%.     

毛细管气相色谱法分析人参中有机氯农药残留量

本文采用高分离效能的毛细管气相色谱柱和高灵敏度的电子捕获检测器，成功地分离和检测了常见的有机氯农药六六六，滴滴涕，六氯苯，五氯硝基苯，七氯，氯甲桥萘等十二种组分，提供了一种分析人参中有机氯农药残留量的方法。     

Towards on-line SEC-GC of pesticide residues? The problem of tailing triglyceride peaks

SEC is used for clean-up of food extracts obtained for analysis of pesticide residues primarily to remove high molecular weight material, among which fat may be present at the largest concentrations. The triglyceride peak, which is usually very large, is eluted before the components of interest. The problem described in this paper deals with the tail of the triglyceride peak: this may intrude into the fraction containing the pesticides and contaminate the GC.     

用反相高效液相色谱研究含氟酰胺类新农药的定量构效关系

本文证明含氟酰胺类新农药在ＲＰ－ＨＰＬＣ上的保留时间与其分配系数具有很好的相关性，引入色谱保留值作为新的理化参数，采用逐步回归分析建立了农药的构效关系的数学模型，为阐明含氟农药的作用机制和新农药的创制研究提供了一个有效的途径。     

Simultaneous determination of pentachlorophenol and carbaryl in water

Summary A rapid method for the simultaneous determination of pentachlorophenol (PCP) and Carbaryl in water is described. A 1 liter water sample is extracted with hexane after acidification with concentrated H₂SO₄. After evaporation to a small volume, the extract is analyzed by gas chromatography-mass spectrometry, operating in the selected ion monitoring mode. Estimated detection limits are 0.08 g L^–1 for PCP and 0.11 g L^–1 for Carbaryl, with recoveries of 96% for PCP and 97% for Carbaryl.     

毛细管气相色谱法测定水体及土壤中溴氟菊酯农药的残留量

建立了新品农药溴氟菊酯在水体及土壤中残留量的测定方法，采用石油醚＋丙酮（３＋１）混合溶剂提取，经浓硫酸＋无水乙醇（１＋１）纯化，用毛细管气相色谱电子捕获检测器测定。该法检出限为０．１×１０－９～２×１０－９，回收率７２．６％～１００．５％，变异系数１．６％～８．５％。     

毛细管气相色谱法测定中药材中多种拟除虫菊酯农药残留量

研究了气相色谱法测定中药材中多种拟除虫菊酯类残留量的分析方法。样品经正己烷．丙酮混合液[V（正己烷）：V（丙酮）=1：1]提取，氟罗里硅土层析柱净化，采用毛细管色谱柱分离，GC-ECD可同时测定8种拟除虫菊酯类农药残留量，回收率为76．6％～104．2％。     

Comparison of two vibrational procedures for the direct determination of mancozeb in agrochemicals

The direct determination of mancozeb in agrochemicals has been made by diamond attenuated total reflectance (ATR) Fourier transform infrared spectroscopy in the middle range (DATR-MIR) and diffuse reflectance infrared Fourier transform spectroscopy in the near range (DR-NIR) methods using in both cases a previous identification of the samples using a dendrographic classification and an appropriate partial least squares (PLS) calibration established from a set of nine external standards and optimized for each type of sample. It was analyzed a heterogeneous population of 11 samples obtained from the Spanish market, containing different co-formulated products, such as fosetyl-Al, copper oxychloride, metalaxyl or cymoxanil. High performance liquid chromatography (HPLC) was used as reference method for validation of both vibrational strategies. The close agreement between values found for both, DATR-MIR and DR-NIR methods, and reference HPLC values indicates the accuracy and reliability of the proposed techniques for the direct determination of mancozeb in commercially available formulations.     

Fe3O4@Au纳米星颗粒作为循环SERS基底用于农药残留物的检测

本文首先采用共沉淀的方法制备了Fe3O4纳米颗粒,随后经柠檬酸钠和对苯二酚还原氯金酸的方法在Fe3O4纳米颗粒的表面生成刺状Au纳米结构,进而获得Fe3O4@Au纳米星颗粒。该Fe3O4@Au纳米星颗粒作为SERS基底,用作农药残留物福美双和敌瘟磷的检测。由于高密度的Au纳米结构的尖端效应,该基底显示出高敏感的SERS活性。最后利用Fe3O4纳米颗粒的磁性,将其用于循环SERS测试,研究了其循环使用特性。