SPE水电解催化剂研究进展

作为一种高效的制氢技术,固体聚合物(SPE)水电解技术受到越来越多的研究人员的关注与研究。介绍了最近几年内SPE水电解技术在析氢、析氧催化剂、催化剂载体及催化剂制备工艺等方面的研究进展。指出目前限制SPE技术商业化的关键仍是催化剂成本过高和活性不强,因此未来研究的重点应当是高性能二元或多元催化剂和耐腐蚀催化剂载体的制备。     

1000MW超超临界机组FCB试验

在电网出现突发性故障时,具备机组快速甩负荷(FCB)功能的机组可快速减负荷并迅速转为带厂用电作孤岛运行,随时可恢复对外送电,大大缩短电网恢复时间。根据外高桥二期实现FCB的经验,外高桥三期1 000 MW超超临界机组在工程设计阶段就对系统设计和配置作了进一步的改进和优化,包括机组连锁方式的变化,低压旁路和除氧水箱容量的增加,再热安全门型式的改进,给水泵和所配汽轮机的优化等。介绍了在FCB时的旁路系统、高压加热器及除氧水箱等的特殊控制方式。通过全真工况的75%负荷及100%负荷FCB试验的成功,再次证明了超超临界大机组实现FCB的可行性和技术的成熟性。     

Applications of sample preparation techniques in the analysis of pesticides and PCBs in food

Pesticides and polychlorinated biphenyls (PCBs) are found in various parts of the environment in quite small concentrations, but they accumulate and thus become a threat to human health and life. A review is focused on the application of some popular techniques for sample preparation in analysis of these compounds in food. Even with the emergence of advanced techniques of final analysis, complex matrices, such as food, require extensive sample extraction and purification. Traditional sample preparation techniques are time consuming and require large amount of solvents, which are expensive, generate considerable waste, contaminate the sample and can enrich it for analytes. There have been many sample preparation techniques proposed to meet the requirements connected with the multiplicity of food. Optimal sample preparation can reduce analysis time, sources of error, enhance sensitivity and enable unequivocal identification and quantification. Sample extraction and purification techniques are discussed and their most recent applications in food analysis are provided. This review pointed out that sample preparation is the critical step.     

Apatite ore mine tailings as an amendment for remediation of a lead-contaminated shooting range soil

This study investigated the use of tailings from apatite ore beneficiation in the remediation of a heavily contaminated shooting range soil. The tailings originating in Siilinjärvi carbonatite complex, Finland, consist of apatite residues accompanied by phlogopite and calcite. In a pot experiment, organic top layer of a boreal forest soil predisposed to pellet-derived lead (Pb) was amended with tailings of various particle-sizes (Ø > 0.2 mm, Ø < 0.2 mm and unsieved material) differing in their mineralogical composition. After 9-, 10-, 14- and 21-month incubation, the samples were monitored for tailings-induced changes in the different Pb pools by means of sequential fractionation. Following the incubation, the samples were extracted with water and the extracts were analyzed for Pb species distribution by means of a cation exchange resin. The results revealed that Pb was continuously released from the shotgun pellet fragments due to weathering. However, the apatite and calcite compartments in the tailings counteracted the mobility of the released Pb through the formation of sparingly soluble fluorpyromorphite and cerussite. Furthermore, the tailings efficiently reduced the bioavailability of Pb by transferring it from the water-soluble and exchangeable pools into the organic one. The material also increased the proportion of the less toxic non-cationic Pb to the total dissolved Pb from the initial level of 5% to 9-12%. The results suggest that the tailings-induced stabilization of Pb may be an environmentally sound remediation technique at polluted sites.     

磁性分子印迹固相萃取食品中的四环素类抗生素残留

采用表面分子印迹技术合成对四环素类抗生素具有特异性吸附性能的Fe3O4@Si O2@MIP核壳型纳米复合材料,经磁分离固相萃取-高效液相色谱（MSPE-HPLC）技术,同时测定样品中3种四环素类抗生素的残留。用扫描电镜（SEM）、透射电镜（TEM）和红外色谱（FT-IR）对其表征。该方法对于四环素、土霉素、金霉素的检出限分别为9.61、7.84、11.93μg/kg,且在线性范围内线性关系良好。最大吸附量为56.28 mg/g。该方法的平均加标回收率在93.71%¹00.88%之间,变异系数1.54%⁷.44%。与非分子印迹聚合物相比,Fe3O4@Si O2@MIP分子印迹聚合物的吸附特异性较强。      

Application of solid phase extraction techniques to analyse volatile compounds in wines and other enological products

Aroma compounds are most closely associated with the volatile fraction of foods. Common analytical separation procedures employed to analyse volatile compounds need, even today, that prior to GC analysis of an aroma or a fragrance, these compounds be concentrated or/and isolated from the non-volatile matrix. This step constitutes a problem that has still not been satisfactorily resolved and for this, several sample preparation methods can be found into the bibliography. This review gives a brief overview of solid phase extraction techniques to analyse volatiles. Procedures such as solid phase extraction (SPE), solid phase microextraction (SPME), stir bar sorptive extraction (SBSE), and the recent solid phase dynamic extraction (SPDE) will be discussed and critically evaluated. Contemporary applications of these techniques to the study of volatile compounds in wine and other enological products will be presented.     

测定菜籽油中酚类化合物样品前处理方法的比较

采用液液萃取(LLE)、固相萃取(SPE)、QuEChERS 3种不同前处理方法提取菜籽油中酚类化合物,并采用超高效液相色谱串联质谱(LC-MS/MS)进行测定,分析比较了3种不同前处理方法对菜籽油中酚类化合物提取效果的影响。结果表明:在3种不同的前处理方法中,QuEChERS前处理方法的提取效果最好,对菜籽油中7种酚类化合物的回收率最高,可达85.16%～101.78%,基质共提物含量最低,为2.04 mg/g;LLE的回收率为66.04%～101.11%,基质共提物含量最高,为6.80 mg/g;SPE的回收率最低,仅为56.98%～83.79%,基质共提物含量为2.30 mg/g。     

磺胺类抗生素分子印迹制备技术与应用进展

分子印迹技术是一种可以特异性地从样品中将待测物分离和富集,降低样品中复杂基质对待测物检测结果的干扰,提高仪器检测精度的前处理技术,现已广泛应用于动物性食品中的兽药残留检测领域。磺胺类抗生素作为最常被检出的兽药之一,其检测方法的优化有着重要研究意义。本文聚焦了近年来磺胺类抗生素分子印迹技术的发展趋势,包括新型功能单体、交联剂和致孔剂的选用,聚合方法的优化以及其应用模式从传统固相萃取材料到快速检测产品的转变,阐述了该技术的优势和目前存在的问题,为磺胺类抗生素分子印迹聚合技术的发展提供参考。     

固相萃取-高效液相色谱法测定畜禽肉中复合硝基酚钠残留

通过碱性溶液提取,再用正己烷萃取除去脂肪,用乙酸调p H为酸性条件后用乙酸乙酯-异丙醇反萃取,浓缩后再通过混合阴离子固相萃取柱净化,最后采用高效液相色谱分离检测。结果:三种复合硝基酚钠组分在0.05¹.0μg/m L范围内其浓度与峰面积呈线性,相关系数均可达到0.999;通过萃取、反萃取以及固相萃取等多种手段净化,样品基质几乎无干扰,检出限可达到0.003⁰.005 mg/kg;通过对0.25、0.5、1.0μg进行加标测试,其回收率在81%⁹5%之间,相对标准偏差均小于10%。      

Corrosion behavior of three bipolar plate materials in simulated SPE water electrolysis environment

The corrosion behavior of titanium (TA2), boron-doped diamond (BDD) coated titanium and mixed metal oxide (MMO) coated titanium were studied using electrochemical impedance spectrum (EIS) in simulated solid polymer electrolyte (SPE) water electrolyte conditions at 80 °C. At imposed anodic potential, after about 240 h electrolysis, the bigger capacitance and reaction resistance values were observed for MMO coated titanium material, which demonstrated that MMO coated titanium has more corrosion-resistance performance. SEM photos showed that ten days electrolysis don't do much harm to MMO coated titanium material in simulated SPE water electrolysis environment.