Theoretical study of the atrazine pesticide interaction with pyrophyllite and Ca2+‐montmorillonite clay surfaces

Atrazine, a pesticide belonging to the s‐triazine family, is one of the most employed pesticides. Due to its negative impact on the environment, it has been forbidden within the European Union since 2004 but remains abundant in soils. For these reasons, its behavior in soils and water at the atomic scale is of great interest. In this article, we have investigated, using DFT, the adsorption of atrazine onto two different clay surfaces: a pyrophyllite clay and an Mg‐substituted clay named montmorillonite, with Ca²⁺ compensating cations on its surface. The calculations show that the atrazine molecule is physisorbed on the pyrophyllite surface, evidencing the necessity to use dispersion‐corrected computational methods. The adsorption energies of atrazine on montmorillonite are two to three times larger than on pyrophyllite, depending on the adsorption pattern. The computed adsorption energy is of about −30 kcal mol⁻¹ for the two most stable montmorillonite‐atrazine studied isomers. For these complexes, the large adsorption energy is related to the strong interaction between the chlorine atom of the atrazine molecule and one of the Ca²⁺ compensating cations of the clay surface. The structural modifications induced by the adsorption are localized: for the surface, close to substitutions and particularly below the Ca²⁺ cations; in the molecule, around the chlorine atom when Ca²⁺ interacts strongly with this basic site in a monodentate mode. This study shows the important role of the alkaline earth cations on the adsorption of atrazine on clays, suggesting that the atrazine pesticide retention will be significant in Ca²⁺‐montmorillonite clays. © 2016 Wiley Periodicals, Inc.     

土壤中残留的阿特拉津及其代谢产物的高效液相色谱和气－质谱联用分析

用一种简便、快速的前处理和高效液相色谱法（ＨＰＬＣ）对土壤样品中残留的阿特拉津及其主要代谢产物脱乙基阿特拉津、脱异丙基阿特拉津和２－羟基阿特拉津进行定量分析，样品添加回收率因土壤种类和化合物而异：７８～１２１％（阿特拉津、脱乙基阿特拉津、脱异丙基阿特拉津）和４０～７５％（２－羟基阿特拉津），最小格测浓度为０．００５ｍｇ／ｋｇ；应用气－质联用法（ＧＣ／ＭＳ）对前三种化合物和脱乙基－脱异丙基阿特拉津进行了定性分析，谱库检索匹配程度达到９０％以上。     

Inclusion Complexes of Atrazine with α-, β- and γ-Cyclodextrins. Evidence by Polarographic Kinetic Currents

The reduction of atrazine in acidic aqueous media on mercury electrodes proceeds only after the protonation reaction. In fact, the efficiency of the reduction process is very low at pHs greater than 4. However, the addition of cyclodextrins (CDs) to neutral aqueous solutions of atrazine yields a kinetically controlled polarographic reduction wave, whose limiting current depends on the size of the CD cavity, and increases with the concentration of the CD itself. In particular, the size of the increase follows the order -CD < -CD < -CD for the same CD concentration. The half-wave potential shifts toward more negative values when the concentration of CDs increases. These findings lead to the conclusion that atrazine and CDs form an inclusion complex, whose stability constant we have estimated, and also that atrazine undergoes protonation facilitated by complexation with CDs. The stability constants of 1:1 complexes evaluated from polarographic data in 0.1M-KCl and at neutral pH for -CD, -CD and -CD are 4900, 1970 and 19000, respectively. The formation of the inclusion complex was indirectly confirmed by UV-Vis measurements in the presence of methylred and phenolphthalein, which both compete with atrazine in the formation of the corresponding inclusion compounds with CDs.     

莠去津对中华绒螯蟹蜕皮激素分泌的影响

为了研究除草剂莠去津对中华绒螯蟹蜕皮激素分泌的影响,利用不同质量浓度(0.001,0.01,0.1,1mg/L)的莠去津对中华绒螯蟹进行染毒处理,采用酶联免疫吸附技术(ELISA)分析其对中华绒螯蟹血清蜕皮激素含量的影响.结果表明:低质量浓度(0.001,0.01mg/L)以及高质量浓度(1mg/L)莠去津暴露后,中华绒螯蟹血清中蜕皮激素含量相较对照组无显著变化,而中间质量浓度0.1mg/L的蜕皮激素含量则显著低于对照组,该质量浓度下中华绒螯蟹的蜕皮会受到一定的影响.     

Determination of Triazine Herbicides and Diuron in Mud from Olive Washing Devices and Soils Using Gas Chromatography with Selective Detectors

Abstract

In the present work, a method for the simultaneous determination of five herbicides, diuron, simazine, atrazine, terbuthylazine and terbutryn by GC‐electron capture detection (ECD) and GC‐thermoionic specific detector (TSD) in soil and mud samples (from olives washing devices) has been developed. Extraction of the herbicides from soil samples was carried out by liquid–solid extraction with ciclohexane/acetone under sonication. In addition, a clean‐up step by solid phase extraction (SPE) using alumina was necessary for mud samples to remove fat residues in the extracts. Spiked soil standards were used for calibration. Limit of detection (LOD) values ranged between 0.2–1.4 ng g^?1 and limit of quantitation (LOQ) between 1.4–2.0 ng g^?1. The precision of the method was satisfactory for all the herbicides analyzed, with RSD values ranging between 7.5%–32.3% and 8.5%–17.8% for 10 and 100 ng g^?1 spiking levels, respectively. The accuracy of the method was checked at three spiking levels (10, 50, and 100 ng g^?1) with recovery values ranging from 74.2%–129.1%. In the case of mud samples, mean recovery values (100 ng g^?1 spiking level) were acceptable for diuron (69.5%) and more satisfactory in the case of triazine herbicides (81.0%–123.0%). Diuron and terbuthylazine were the herbicides most frequently detected in the analyzed samples.     

Perkin-Elmer introduce new gas chromatograph

Abstract

APPLICATIONS OF MASS SPECTROMETRY TO TRACE ANALYSIS. Ed. S. Facchetti, Elsevier, US $78.75, Dfl. 185.00.

QUANTITATIVE AQUATIC BIOLOGICAL INDICATORS. by David J. H. Phillips, Fisheries Research Station Aberdeen, Hong Kong, POLLUTION MONITORING SERIES (1980), 488 pages (including 99 figures, 103 tables, 44 pages of literature references up to 1978, an author index of 10 pages, a species index of 4 pages, and a subject index of 18 pages), linen, format 228 × 148 mm, ISBN 0-85334-884-7, Applied Science Publishers Ltd., London, £26.

DIRECTORY OF POLLUTION CONTROL EQUIPMENT COMPANIES IN WESTERN EUROPE, Third Edition (1980), 588 pages (including an index of 127 pages, which is however-structured somewhat arbitrarily according to types of equipment and according to countries), stiff paper cover, format 210 × 147 mm, ISBN 0 906685 00 1, European Directories, a Division of Inter Company Comparisons Ltd., 23, City Road, London EC1Y 1AA, £30.

HALOGENATED BIPHENYLS, TERPHENYLS, NAPHTHALENES, DIBENZODIOXINS AND RELATED PRODUCTS, by R. D. Kimbrough (ed.) (Elsevier Biomedical Press, R.V., Amsterdam, NL. U.S. $95.00, Dfl 195.

CHROMATOGRAPHY AND THE ENVIRONMENT, Environmental problem solving using gas and liquid chromatography, R. L. Grob and M. A. Kaiser, Elsevier, Amsterdam, 1982, XII + 240 pages, ISBN 0-444-42065-7     

尿中莠去津去烃基代谢物的特丁二甲硅烷基衍生化/气相色谱-质谱联用分析法

建立了尿中除草剂莠去津(ATRZ)代谢物去乙基莠去津(DEA)、去异丙基莠去津(DIA)及去乙基去异丙基莠去津(DDA)的分析方法.尿样加入内标2-氨基-4-甲氧基-6-甲基-1,3,5-三氮嗪(AMMT),碱化后用高极性GDX501大孔树脂吸附、乙酸乙酯洗脱进行固相萃取,萃取物在乙腈溶剂中用N-甲基-N-特丁二甲硅烷...     

氯对粉末活性炭吸附水中阿特拉津性能的影响

为探讨氯对粉末活性炭(PAC)吸附水中阿特拉津效能的影响及预氯化与PAC联用工艺处理水中特定污染物时的工艺优化措施,采用小试试验研究氯的投加时间、投加量对PAC吸附阿特拉津的容量及速度的影响.结果表明,氯会显著降低PAC吸附阿特拉津的容量和速度,且氯在腐殖酸溶液中的降低程度小于在纯水中的;在腐殖酸溶液中,氯的投加时间影...     

溶剂法生产莠去津工艺的改进

以三氯乙烯做溶剂,以三聚氯氰、异丙胺与乙胺为原料,经过2次取代合成莠去津.通过探索和单因素实验得到最佳合成条件:三聚氯氰和三氯乙烯物料比为1∶6.25(g/mL)；分2次加入三聚氯氰,一取代反应过程控温为(25±1)℃,保温反应为30 min；二取代反应过程控温为(45±1)℃,保温反应为90 min.产品纯度达94％以上,收率达92％以上.     

节杆菌AD1菌株的阿特拉津氯水解酶基因在大肠杆菌中的表达

用PCR方法从节杆菌AD1菌株中扩增出完整的阿特拉津氯水解酶基atzA，该基因与载体pGEM-T连接成重组质粒以后，转化大肠杆菌DH5a，表达出了有活力的阿特拉津氯水解酶。