高效液相色谱法同时测定鳗鱼及其制品中八种磺胺类药物

建立了高效液相色谱测定鳗鱼及其制品中磺胺嘧啶、磺胺甲基嘧啶、磺胺二甲嘧啶、磺胺甲氧嗪、磺胺甲嗯唑、磺胺间甲氧嘧啶、磺胺间二甲氧嘧啶、磺胺喹嗯啉等八种磺胺类药物残留量的方法。研究了鳗鱼及其制品中八种磺胺类药物残留的提取、净化和高效液相色谱条件。样品经二氯甲烷提取、MCX阳离子固相萃取小柱净化，以Cloversil C18柱，甲醇、1％乙酸(V／V)梯度洗脱分离，紫外检测器检测、外标法定量。结果表明，样品添加0．1mg／kg的回收率为80％～93％，定量测定低限为0．02mg／kg。方法已应用于实际样品的测定。     

Electric Eel-Inspired Soft Electrocytes for Solid-State Power Systems

As the demand for power systems, including portable ones, is growing at an ever-faster pace, many studies are approaching to discover innovative materials for current battery technology or replace the existing ones with new systems through mimicking living things or nature. Here, a soft, solid-state power storage system featuring electric eel-inspired artificial electric organs capable of converting the chemical potential of an ionic gradient into electricity is introduced. These organs are constructed through the assembly of low and high ion-concentrated zwitterionic gel films with cation- and anion-selective intermembranes, which generate a rechargeable open-circuit voltage of ≈135 mV. Combined use of a chemically synthesized room-temperature ionic liquid and a high-boiling point organic solvent as ion-conducting electrolyte allows electric organs to withstand extreme temperatures ranging from −20 and 100 °C, while the thin and stretchable constituent layers facilitate mechanical flexibility without compromising electrical performance. Scalable integration of electric organs in series and parallel configurations achieves high levels of voltage and current outputs, and employment of origami folding geometry enables on-demand discharge upon self-registered folding, paving the way for portable, high-voltage energy sources in the fields of wearable electronics and soft robotics.     

超高效液相色谱-串联质谱法同时测定鳗鱼中32种兽药残留

目的 建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)同时测定鳗鱼中13种磺胺类、15种喹诺酮类和4种四环素类兽药残留的分析方法。方法 鳗鱼试样采用乙二胺四乙酸二钠(ethylenediaminetetraacetic acid disodium salt, Na2EDTA)-Mcllvaine提取液进行提取, HLB固相萃取柱净化, Waters ACQUITY UPLC BEH C18色谱柱分离, 以0.1%甲酸乙腈和0.1%甲酸水溶液作为流动相进行梯度洗脱; 电喷雾正离子模式下, 以多反应监测(multiple reaction monitoring, MRM)方式采集数据进行定性与定量分析, 外标法定量。结果 磺胺类、喹诺酮类及四环素类药物分别在2~50、2~50、5~100 μg/kg浓度范围内线性相关性良好, 相关系数均大于0.99; 不同加标水平的平均回收率为82.6%~110.2%, 相对标准偏差(relative standard deviations, RSDs)为3.2%~13.9%, 检出限(limits of detection, LODs)和定量限(limits of quantification, LOQs)分别为0.3~2.0 μg/kg和1.0~5.0 μg/kg。结论 本方法快速简便、灵敏可靠, 适合大批量鳗鱼中同时快速对磺胺类、喹诺酮类及四环素类兽药残留进行定性和定量检测。     

微波消化法测定鳗鱼中痕量铅的最佳条件研究

采用微波消化-原子吸收光谱法测定鳗鱼中痕量铅。研究铅含量随着微波消化的压力、时间、混合酸比例及称样量等因素的变化而变化的规律,并通过单因素及正交试验确定了微波消解鳗鱼的最佳条件,即微波压力为2MPa、作用时间为10min、混合酸的比例为6∶2、称样量为0.2g,283.30nm波长处铅的检出限为0.008mg/kg(3s),线性范围为0～80μg/L,样品分析结果的相对标准偏差2.6%(n=7),加标回收率在95%～105%,该法简便、快速、灵敏、准确、线性范围宽。     

Brominated,chlorinated and mixed brominated/chlorinated persistent organic pollutants in European eels (Anquilla anquilla) from Latvian lakes

Fifty-eight European eel (Anquilla anquilla) specimens collected from five Latvian lakes were investigated for six groups of persistent organic pollutants (POPs), including polychlorinated, polybrominated and mixed bromo-chloro dibenzo-p-dioxins and dibenzofurans (PCDD/DFs, PBDD/DFs and PXDD/DFs), polychlorinated and mixed bromo-chloro biphenyls (PCBs and PXBs) and polybrominated diphenyl ethers (PBDEs). PCDD/DFs and PCBs were found to occur in the range 0.85–15.8 pg Total-WHO₂₀₀₅-TEQ g^?1 f.w., and concentrations in most of the samples were below the maximum levels specified in European Commission Regulation (EU) No. 1259/2011. The summed concentrations of 27 PBDEs (∑_PBDE) and 16 non-dioxin-like PCBs (∑_NDL-PCB) were in the ranges of 0.28–26.7 and 6.37–320 ng g^?1 f.w., respectively. PBDD/DFs, PXDD/DFs and PXBs show average upper-bound concentrations of 0.05, 0.06 and 0.01 pg TEQ f.w. and collectively contributed 3.4% to the sum TEQ of dioxin-like compounds. The highest contaminant concentrations were measured in samples from lakes near the Baltic Sea and the industrialised area near Riga (Liepajas and Kisezers lakes). A correlation of POP concentration with the length of collected specimens was observed.     

Mechanically reshaping stream banks alters fish community composition

Mechanically reshaping stream banks is a common practice to mitigate bank erosion in streams that have been extensively channelised and lowered for land drainage. A common perception regarding this activity is that fish populations will be largely unaffected, at least in the short term, because the low‐flow wetted channel remains undisturbed. However, the response of fish populations to this practice has rarely been quantitatively evaluated. Using a Before‐After‐Control‐Impact design, we assessed fish community responses to a catchment‐scale bank reshaping event in a fourth‐order low‐gradient stream that drains an intensive agricultural landscape. Quantitative electric fishing and fish habitat data were collected 2 months before and annually for 3 years after the reshaping event. After reshaping, deposited fine sediment levels increased in impact reaches, and there was a significant reduction in anguillid eel biomass (by 49%). In contrast, densities of obligate benthic gobiid bully species increased significantly in impact reaches—potentially due to reduced predation pressure from eels. Three years after bank reshaping, fish community structure had largely returned to its preimpact state in the reshaped areas. Our results suggest that, even in highly modified stream channels, further bank modification can reduce instream habitat quality and displace eels for at least 1 year. Managers should endeavour to use bank erosion control measures that conserve bank‐edge cover, especially in streams with populations of anguillid eels, because these fish are declining globally.     

Reaction of silver eels to artificial light sources and water currents: An experimental deflection study

Flume experiments demonstrated a strong avoidance reaction among silver eels (Anguilla anguilla) to light. In the experimental flume, 65% of eels could be deflected with a fluorescent lamp at an illumination level of about 3–5 mLux. Silver eels preferred a swimming route using the highest water velocity (25 cm s⁻¹). In the dark, significantly more silver eels (75%) chose the compartment with the highest water velocity when given a choice between different water velocities. In a situation with differences in both illumination level and water velocity, the deflection by light was stronger than the attraction caused by the higher water velocity, although the rate of deflection caused by light was slightly influenced by water velocity. These results encourage the development of light‐induced deflection systems at (hydro)power stations in order to lower mortality of eels. Copyright © 1999 John Wiley & Sons, Ltd.