气相色谱-质谱法测定环境水体中24种半挥发性有机物

采用液液萃取-气相色谱-质谱法同时测定环境水体中的24种半挥发性有机物。水样经二氯甲烷萃取,萃取液经浓缩定容后在DB-5MS毛细管色谱柱上分离,质谱中选择电子轰击离子源-选择离子监测模式,以菲-D10为内标物进行定量。24种化合物的质量浓度在一定范围内与其峰面积呈线性关系,检出限为0.03~0.28μg·L-1。加标回收率在70.1%~128%之间,测定值的相对标准偏差(n=6)小于6%。实际样品分析结果表明,某地地表水和化工区水样中均检出硝基苯类、氯代苯酚类、酞酸酯类等化合物。     

多方位做好实验辅助提升教学质量

以实验技术人员的视角,从不同实验环节出发,全面总结实验辅助工作,并提炼为实验辅助大三部曲和小三部曲。该方面的工作体系源于实验室开设的"化学生物学综合实验",反哺了实验室多门实验课程,取得了良好的效果,促进了实验教学质量的提升,同时也为环境育人创造了有利的条件。     

Recent trends on electrochemical carbon-based nanosensors for sensitive assay of pesticides

Pesticides are substances or mixtures used to prevent, control, and reduce harmful organisms, are divided into various groups as carbamates, organophosphates, organochlorines, pyrethroids, fungicides, herbicides, and rodenticides. Uncontrolled and long-term use of pesticides has become an important issue that causes environmental pollution and health problems. Therefore, it is necessary to develop effective sensors to determine pesticides in various samples. Electrochemical techniques stand out with high sensitivity, easy application, low cost, and user-friendliness, among other analysis techniques such as spectroscopic and chromatographic methods. Furthermore, carbon nanomaterials are advantageous materials for the sensor design as modification agents due to their unique electrical, physical, electrocatalytic, and chemical features. In this review, the most significant studies on the electroanalysis of pesticides (e.g., carbaryl, carbofuran, chlorpyrifos, malathion, methyl parathion, paraoxon) using carbon-based nanosensors in the last five years are overviewed. In addition, electrochemical methods and the carbon nanomaterials used in these studies are also evaluated.     

环境水镉污染应急处理的药物及条件挑选

探讨了硫酸铝、聚铝、聚铁对环境水体中的镉的沉淀能力,实验证明当在实际环境水样品中调节pH在7-9之间,聚铁或聚铝能对环境水体中的镉很好的沉淀作用,短期作用比较明显,药剂能在30min左右达到2h的处理效果的70%-90%,而长期作用后(18h)能将水体中的镉降低到10μg/L以下,一立方水的用药量在100-400g之间就可以到达很好的处理效果,而且无二次污染,可为环境水中镉污染的应急处理药品.     

谷氨酸钠溶液514nm激光拉曼光谱受环境光影响的研究

探讨了环境光的存在对谷氨酸钠溶液的514 nm绿色激光激发的拉曼光谱的影响.研究表明不同的环境光、自然光和室内荧光灯光均会对514 nm激光拉曼光谱产生干扰,存在着特征干扰峰.自然阳光干扰较小;而荧光灯光表现为1127、2107 cm-1和2170 cm-1等3个明显尖锐的脉冲峰,不能忽略.建议在进行谷氨酸钠溶液514 nm绿色激光拉曼光谱检测时,须在暗室或暗罩中进行,以完全隔离环境光的影响.     

A Branch-and-price Algorithm for the Multi-Vehicle Covering Tour Problem

In this paper, we propose a Branch-and-price (BP) algorithm and a Column Generation Heuristic (CGH) for the Multi-Vehicle Covering Tour Problem (m-CTP). Specific dominance and extension pruning rules are introduced to accelerate the resolution of the pricing problems. To the best of our knowledge, this is the first work dedicated to the exact resolution of m-CTP. The algorithm managed to solve about 30% of the instances in our test bed, within a 4 hour CPU time limit. Our preliminary computational experiments suggest that both the lower bounds provided by the formulation behind BP and the CGH upper bounds are of good quality.     

Improvement of the SOS/UMU Test for Preliminary Screning of Mutagens

Abstract

A short-term system to detect environmental mutagens is presented by using a plasmid (pSK1002) carrying a fused gene umuC′-′lacZ introduced into Salmonella typhimurium TA1535. Higher sensitivity, repeatability, and simplicity were achieved when (1) the culture volume taken from 2hrs after treatment with test compound was increased to 1.5ml diluted with distilled water to 2.5ml, (2) the 15μ 1 of 3% SDS solution saturated with chloroform was used as the disruptor of the cell membrane. and (3) an incubation -temperature of 37°C was used. At the above experimental conditions, the time required for the mutagen test was shortened to 3hrs. Based on the results of the present study, it seems that the improved SOS/umu test is useful for screening of mutagenic complex environmental mixtures.     

Research Problems from the BCC21

A collection of open problems, mostly presented at the problem session of the 21st British Combinatorial Conference.     

A combination of accreditation and certification in an evolving process at EMPA: A management system to meet ISO 9001, ISO 14001 and EN 45001

 The Swiss Federal Laboratories for Materials Testing and Research (EMPA) have established a quality assurance system based on EN 45001 which meets the requirements for accreditation of all EMPA's testing activities. As testing is only a part of EMPA's range of activities, and is performed in decentralised departments, the system does not satisfy the management needs. The fundamental reorganisation of EMPA's St. Gallen site was used as an opportunity to implement an overall process-oriented management system which also included quality and the needs for accreditation. Later, an environmental management system was added and then certified for ISO 9001 and 14001. The system consists of a "Management Manual" for the St. Gallen site and a customised "Quality Manual" for each department. One of the key elements is a comprehensive review and planning procedure covering all business aspects.     

PLANE ELASTIC PROBLEMS OF DIFFERENT MEDIA WITH CRACKS ON THE INTERFACE

The equllibrium problem for the infinite elastic plane consisting of two different media with many cracks on the interface is discussed.It is transferred to a boundary value problem for analytic functions and then further reduced to a singular integral equation,the unique solvability and an effective method of solution for which are eatablished.A practical example in applications is illustrated,the solution of which is obtained in closed form.