液相飞行时间质谱(LC/MSD TOF)和液相色谱/离子阱质谱(LC/MSD Trap)测定色拉蔬菜中的氯烟碱类杀虫剂

本工作考察了液相色谱／飞行时间质谱检测器(LC／MSDTOF)和液相／离子阱质谱检测器(LC／MSD Trap)联用技术分析一些氯烟碱类杀虫剂的可行性．杀虫剂包括：啶虫咪(acetamiprid)，吡虫啉(imidacloprid)和噻虫啉(thiacloprid)．色拉蔬菜有四种：番茄、辣椒、莴苣和黄瓜．本文介绍的内容包括三种氯烟碱类杀虫剂的LC／MSDTOF和LC／MSD Trap质谱，TOF获得的实验分子式和四种蔬菜基质中氯烟碱类杀虫剂的MS／MS碎片离子．同时也将详细介绍样品制备程序以及色拉蔬菜中杀虫剂的回收、最低检测限(MDL)的质谱质量、线性，使用TOF和Trap对纯溶剂和四种蔬菜提取物中杀虫剂的定量分析．给出了来自市场的实际色拉蔬菜样品中杀虫剂的分析结果．     

Pilot project of biogas production from pig manure and urine mixture at ambient temperature in Ventanilla (Lima, Peru)

Parque Porcino de Ventanilla has an extension of 840ha with 2200 farmers dedicated to pig production. There is a lack of services in the area (i.e., water supply, electricity, or waste collection). Anaerobic treatment of pig manure would replace current dumping and incineration, reducing environmental pollution and hazards to public health, as well as providing an organic fertilizer and biogas. The objective of the present work was to study the viability of ambient temperature anaerobic digestion of pig manure diluted in urine, by means of on-site pilot scale reactors. The final goal was to establish design parameters for anaerobic digesters to be implemented; since it was part of a project to improve life conditions for the farmers through the incorporation of better management techniques. Experiments were carried out in a low-cost pilot plant, which consists of three anaerobic digesters (225L total volume), without heating or agitation, placed in a greenhouse. The start-up of the digestion process was performed with a mixture of temperature adapted pig manure-sludge and fresh rumen, and showed a good performance regardless of the dilution of pig manure with water or urine, which is a key parameter due to the scarcity of water in the area under study.     

Magnetic properties of the microorganism Candidatus Magnetoglobus multicellularis

Magnetotactic microorganisms use the interaction of internal biomineralized nanoparticles with the geomagnetic field to orientate. The movement of the magnetotactic multicellular prokaryote Candidatus Magnetoglobus multicellularis under an applied magnetic field was observed. A method using digital image processing techniques was used to track the organism trajectory to simultaneously obtain its body radius, velocity, U-turn diameter, and the reorientation time. The magnetic moment was calculated using a self-consistent method. The distribution of magnetic moments and radii present two well-characterized peaks at (9 ± 2) × 10⁻¹⁵ and (20 ± 3) × 10⁻¹⁵ A m² and (3.6 ± 0.1) and (4.3 ± 0.1) μm, respectively. For the first time, simultaneous determination of the distribution of the organism radii and magnetic moment was obtained from the U-turn method by a new digital imaging processing. The bimodal distributions support an organism reproduction process model based on electron microscopy observations. These results corroborate the prokaryote multicellular hypothesis for Candidatus M. multicellularis.     

Hydrochemical characteristics and quality assessment of shallow groundwater in Yangtze River Delta of eastern China

Environmental Science and Pollution Research - Water resource is in high demand within the Yangtze River Delta, given its developed economy. Long-term exploitation of this resource has posed risks...