HPLC-ICP-MS快速、准确测定鱼肉组织中的砷甜菜碱(AsB)

采用高效液相色谱与电感耦合等离子体质谱法联用测定鱼肉样品中的砷甜菜碱,样品前处理采用快速溶剂萃取,分析方法快速、准确。通过测定鱼肉中砷甜菜碱的标准参考物质以及在欧洲实验室间对盲样进行比对实验,进一步验证了该方法的有效性。采用等度洗脱一次可分离分析多达6种不同形态的砷,仅需10分钟。通过优化方法,最大程度地简化了费时的样品前处理步骤并实现了对大批量样品进行自动萃取与分析。该实验分别比较了标准加入法与外标法的测定结果,结果显示两者并无显著差异,表明HPLC＿ICP＿MS法受基体影响极小。萃取过程中可自动处理多达24个样品,所建立的HPLC＿ICP＿MS分析方法稳定、可靠,能连续进样50针以上,相当于总运行时间在12小时以上。因此,该方法适用于毒物甄别研究中快速、准确地判断砷总含量较高的鱼肉样品中无毒砷甜菜碱的比例。     

Capturing market impacts of farm level policies: a statistical extrapolation approach using biophysical characteristics and farm resources

Technical change at the farm level or changes in input prices often have an impact on the firm's supply function, which in turn affect their economic and environmental performance. These changes can take place in numerous ways. This paper presents a methodology that increases the consistency of supply responses across various sets of agricultural products and most representative farm typologies in Europe, with a market model based on a statistical response function approach. Since most farm simulation models are limited to a subset of regions and farm types, the linkage to an aggregated model requires a procedure for expanding these results to non-sample regions to achieve full regional coverage. This paper addresses theoretical aspects related to the consistency between micro and market level models. The proposed approach is applied using a consistent set of simulation results from farm models in seven European regions. Our results show a fairly stable behaviour of the farm models considered for the analysis and quite good fit of the estimated response surface. As results are still preliminary we critically reflect on the applicability of this method in addressing further needs on up-scaling of other economic as well as environmental indicators.     

Derivation of correlations to evaluate the impact of retrofitted post-combustion CO2 capture processes on steam power plant performance

When integrating a post-combustion CO₂ capture process and CO₂ compression into a steam power plant, the three interface quantities heat, electricity and cooling duty must be satisfied by the power plant, leading to a loss in net efficiency. The heat duty shows to be the largest contributor to the overall net efficiency penalty of the power plant. Additional energy penalty results from the cooling and electric power duty of the capture and compression units.In this work, the dependency of the energy penalty on the quantity and quality of the heat duty is analyzed and quantified for a state-of-the-art hard coal fired power plant. Furthermore, the energy penalty attributed to the additional cooling and power duty is quantified. As a result correlations are provided which enable to predict the impact of the heat, cooling and electricity duty of post-combustion CO₂ capture processes on the net output of a steam power plant in a holistic approach.     

Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace

High temperature combustion experiments of waste printed circuit boards (PCBs) were conducted using a lab-scale system featuring a continuously-fed drop tube furnace. Combustion efficiency and the occurrence of inorganic bromine (HBr and Br₂) were systematically studied by monitoring the main combustion products continuously. The influence of furnace temperature (T) was studied from 800 to 1400 °C, the excess air factor (EAF) was varied from 1.2 to 1.9 and the residence time in the high temperature zone (RT_HT) was set at 0.25, 0.5, or 0.75 s.Combustion efficiency depends on temperature, EAF and RT_HT; temperature has the most significant effect. Conversion of organic bromine from flame retardants into HBr and Br₂ depends on temperature and EAF. Temperature has crucial influence over the ratio of HBr to Br₂, whereas oxygen partial pressure plays a minor role. The two forms of inorganic bromine seem substantially to reach thermodynamic equilibrium within 0.25 s. High temperature is required to improve the combustion performance: at 1200 °C or higher, an EAF of 1.3 or more, and a RT_HT exceeding 0.75 s, combustion is quite complete, the CO concentration in flue gas and remained carbon in ash are sufficiently low, and organobrominated compounds are successfully decomposed (more than 99.9%).According to these results, incineration of waste PCBs without preliminary separation and without additives would perform very well under certain conditions; the potential precursors for brominated dioxins formation could be destroyed efficiently. Increasing temperature could decrease the volume percentage ratio of Br₂/HBr in flue gas greatly.