农药化学中的绿色化学

绿色化学是从根本上消除环境污染的必由之路。由于某些传统农药是引起环境污染的一个重要因素,因而对农药化学中的绿色化学进行研究和推广具有非常重要的意义。本文应用绿色化学原理,对农药化学中的一些绿色化学方法和技术作了简单介绍。     

Recent advances in round-the-clock photocatalytic system: Mechanisms,characterization techniques and applications

Solar energy-driven semiconductor photocatalysis has gathered increasing interest in the field of energy and environmental applications. However, a vital problem that limits its application is that photocatalysis requires a continuous light source to perform redox reaction. The ability of keeping catalytic activity in the dark has been the ultimate goal for the wide application of photocatalysis. More and more efforts have been paid to develop photocatalysts to perform photocatalytic reactions under both light and dark conditions, which is so called “round-the-clock photocatalytic system” (RTCPS). RTCPS with an ability of energy storage can work well under both daytime and nighttime, which widely used in the removal of heavy metal ion, the degradation of organic pollutant, disinfection and hydrogen generation. The important potential of RTCPS necessitate timely reviews of the recent advances to streamline efforts. Thus, this review aimed to summarize the recent advances in RTCPS, including the mechanism, characterization techniques and applications. Moreover, future challenge and research direction on the mechanistic study, material design and potential applications are also discussed.     

人工神经网络光度法同时测定土壤中铅-镉-镍

研究了以4－（2－吡啶偶氮）－间苯二酚（PAR）为显色剂、十二烷基硫酸钠（SDS）为增敏剂、乙酸－乙酸钠为缓冲液，在水相中对铅、镉、镍进行同时测定。利用二次回归正交组合设计，对体系因子进行了优化。以苏州吴县水稻田土壤为研究对象，利用反向人工神经网络对其中铅、镉、镍的全量、有效态、活化态分别进行了同时测定，预测结果与AAS法所测结果基本一致。     

The EC networking on elemental speciation revisited

In Europe, the EC-funded Thematic Network Speciation 21 was instrumental in disseminating the existing knowledge about chemical speciation of trace elements. It created a forum in which analytical chemists working in method development were mixed with potential users from industry and representatives of legislative bodies. This endeavour is continuing in the currently established European Virtual Institute for Speciation Analysis (EVISA). Although there already exists substantial know-how in Europe for the speciation of a number of substances, such as organo-arsenic, organo-tin and organo-mercury compounds, to name just these three groups, there is an urgent need to enforce the analytical potential in speciation analysis on a much wider scope of compounds capable of providing data of a suitable quality. The ensuing need for quality assurance of the analytical procedures requires the analysis of representative reference materials, certified for the relevant species. Last but not least, where applicable, the European-wide legislation should be adapted to focus on toxic species of the elements, rather than the total element.Presented at BERM-9—Ninth International Symposium on Biological and Environmental Reference Materials, June 15–19, 2003, Berlin, Germany. Disclaimer The opinions expressed in the present article are entirely those of the authors. They do not represent the opinion of the European Community.     

HUMANN-based system to identify benzimidazole fungicides using multi-synchronous fluorescence spectra: An ensemble approach

In this paper, we approach, using neural computation and ensemble systems, a pattern classification problem in fluorescence spectrometry, the resolution of difficult multi-fungicide mixtures (overlapping), specifically the benzimidazole fungicides, benomyl, carbendazim, thiabendazole and fuberidazole. These fungicides are compounds of an important environmental interest. Because of this, from an analytical point of view, it is interesting to develop sensitive, selective and simple methods for their determination. Fluorescence spectrometry has proven to be a sensitive and selective technique for determination of many compounds of environmental interest, but in some cases it is not enough. HUMANN is a hierarchical, unsupervised, modular, adaptive neural net with high biological plausibility, which has shown to be suitable for identification of these fungicides and organochlorinated compounds of environmental interest. We propose two modular artificial intelligent systems, with a structure of pre-processing and processing stage, a multi-input HUMANN-based system, using multi-fluorescence spectra as input to the system, and a HUMANN-ensemble system. We analyze the optimal configuration of inputs and the ensemble in order to obtain better results. We study such figures as precision and sensitivity of the method. Our proposal is a smart, flexible and effective complementary method, which allows reducing the analytical and/or computational complexity of the analysis. Figure Stages in identification of benzimidazole fungicides Based on a contribution presented at the XIII International Symposium on Luminescence Spectrometry held in Bologna, Italy from Sept. 7–11, 2008.     

不同基质中s1p1组态的能级

研究了s1p1组态能级位置及能级劈裂同基质的关系. 结果表明, Sn2+的A、B、C带能级和In+、Tl+的A、B带能级位置同基质的环境因子he呈线性关系, 能级能量随he的增大而减小, 给出了相应的经验公式, 并计算了In+和Tl+自由离子的A、B带能级能量. 计算结果同实验数据十分吻合, 最大的偏差来自Tl+的B带, 偏差率仅为-7.34%. 随基质he的增大, 高能级能量比低能级下降得更快, A、B和C带间的能级间距相应变小. 通过对比发现: Sn2+、In+、Tl+的A、B带能级对基质的敏感性存在较大差异, Sn2+能级能量受基质变化影响最大, In+的能级能量随基质变化最小. 更为重要的是, 发现随着he的增大, Sn2+、In+和Tl+的A、B和C带能级劈裂相应变小, 甚至不再劈裂, 很好地解释了光谱现象.     

Assessment of priority pesticides,degradation products,and pesticide adjuvants in groundwaters and top soils from agricultural areas of the Ebro river basin

Gas chromatography-mass spectrometry (GC/MS) was employed for the determination of 30 widely used pesticides including various transformation products and alkylphenols in water and agricultural soils with the aim of assessing the impact of these compounds in agricultural soils and the underlying aquifer. The extraction, clean-up, and analytical procedures were optimized for both water and soil samples to provide a highly robust method capable of determining target analytes at the ppb–ppt level with high precision. For water samples, different solid-phase extraction cartridges and conditions were optimized; similarly, pressurized liquid extraction conditions were tested to provide interference-free extracts and high sensitivity. Instrumental LODs of 3–4 pg were obtained. The multi-residue extraction procedures were applied to the analysis of groundwaters and agricultural soils from the Ebro river basin (NE Spain). Most ubiquitous herbicides detected were triazines but some acetanilides and organophosphorus pesticides were also found; the pesticide additive tributylphosphate was found in all water samples. Levels varied between 0.57 and 5.37 μg/L in groundwater, whereas nonylphenol was the sole compound detected in soil. Alkylphenols are used as adjuvants in pesticide formulations and are present in sludges employed as soil fertilizers. Occurrence was found to be similar to other environmental studies.     

The mutual responses of higher plants to environment: physiological and microbiological aspects

Higher plants are different from animals in many aspects, but the important difference may be that plants are more easily influenced by environment. Plants have a series of fine mechanisms for responding to environmental changes, which has been established during their long-period evolution and artificial domestication. The relationship between higher plants and environment is influenced mutually. The component in environment provides higher plants with nutrients for shaping themselves and higher plants simultaneously bring photosynthetic products and metabolites to surroundings, which is the most important part of natural circle. Photosynthetic products are realized mainly by physiological mechanisms, and microbiological aspects in environment (for instance, soil environment) impact the above processes greatly. The complete understanding of the relationship will extremely promote the sustainable utilization of plant resources and make the best use of its current potential under different scales.     

Optical immunosensors for environmental monitoring: How far have we come?

Immunosensing has proved to be a very interesting research area. This review discusses what has actually been achieved in the field of optical immunosensing for environmental screening, and what still needs to be done. The review is presented from a practical point of view. In terms of the basic design of the immunosensor, there is a trend towards decreasing assay time; indeed, this has been reduced from 15–20 minutes to less than 5 minutes. Another goal is to simplify the manifold, and label-free approaches combining indirect assay formats and the detection of antibody binding are popular. Rapid displacement assays have also been investigated thoroughly. In terms of some important features of immunosensing devices, the reusability of the sensing element has been studied in great depth, and working lifetimes of more than five hundred assays can now be found for all assay formats. Multianalyte assays are now being investigated, and current systems are able to monitor 2–3 target compounds, although this number is set to increase greatly (to >30) in the near future. In this sense, an increasing number of publications can be found on microarrays intended for multianalyte determinations. The application of immunosensing to real situations is the main challenge. Immunosensors are barely commercialized and are yet to be established as research or routine tools, due to a lack of validated protocols for a wide range of sample matrices. Regarding compounds considered as analytes, some significant pollutants such as dioxins or pharmaceuticals are rarely chosen as targets, although the current tendency is towards a broader spectrum of analytes. New immunoreagents should be raised for these compounds, for use in immunosensors that can be used as screening tools.     

Hydroxyl radical formation upon dark oxidation of reduced iron minerals: Effects of iron species and environmental factors

Dark formation of hydroxyl radical upon oxidation of reduced iron minerals plays an important role in the degradation and transformation of organic and inorganic pollutants. Herein, we compared the hydroxyl radical formation from various reduced iron minerals at different redox conditions. OH production was generally observed from the oxidation of reduced iron minerals, following the order: mackinawite (FeS) > reduced nontronite (iron-bearing smectite clay) > pyrite (FeS₂) > siderite (FeCO₃). Structural Fe²⁺ and dissolved O₂ play critical roles in OH production from reduced iron minerals. OH production increases with decreasing pH, and Cl^? has little effect on this process. More importantly, dissolved organic matter significantly enhances OH production, especially under O₂ purging, highlighting the importance of this process in ambient environments. This sunlight-independent pathway in which OH forms during oxidation of reduced iron minerals is helpful for understanding the degradation and transformation of various inorganic and organic pollutants in the redox-fluctuation environments.