Fulvic acid enrichment in the microlayer of the Gerlache Inlet Sea (Antarctica): preliminary results

The aim of this work was to study the presence of fulvic acids in Antarctic waters, as they appear to be principal film-forming components in the surface microlayer. We obtained a series of samples during two Antarctic Italian Expeditions in 1998/99 and 2000/01 and studied the distribution and the structural differences between fulvic acids extracted from both microlayer and subsurface waters.

Fulvic acids are concentrated in the microlayer and the enrichment factor between microlayer and subsurface water differs between samples. The enrichment factor values for fulvic acids lie between those found for dissolved organic carbon (DOC) and particulate organic carbon (POC) in the literature. Fulvic acids extracted from the microlayer were found to be different in structure from those present in the subsurface layer and enriched in sulphur content. We hypothesised that sulphur-containing compounds are slightly bound and/or occluded in fulvic acid structures. The sulphur-containing compounds analysed in the microlayer could be dimethylsulfide (DMS) and/or its products stemming from photochemical and biological oxidation reactions.     

原子吸收光谱法测定污水中空心莲子草的Pb和Zn

采用原子吸收光谱法测定空心莲子草根、茎、叶中的pb^2＋、Zn^2＋富集量,及其对pb^2＋、Zn^2＋离子的去除速率进行初步研究.结果表明,低浓度时空心莲子草对pb^2＋、Zn^2＋净化能力第1天可以达到50％左右,5天后累积去除率达90％以上,对两种重金属的富集情况：根＞茎＞叶.     

Overview of nanosorbents used in solid phase extraction techniques for the monitoring of emerging organic contaminants in water and wastewater samples

In this article, we have critically overviewed some interesting articles published in 2015–2019 about the use of the nanosorbents for the extraction of emerging organic contaminants (EOCs) from various environmental samples. Properties, advantages, disadvantages, and the applicability of different categories of nanosorbents used for the extraction of EOCs are evaluated and discussed. The potential applications of these nanomaterials as adsorptive phase in solid-phase extraction (SPE) based techniques are reviewed.     

The removal characteristics of natural organic matter in the recycling of drinking water treatment sludge: Role of solubilized organics

To clarify the role of solubilized organics derived from drinking water treatment sludge (DWTS) in the elimination of natural organic matter (NOM) in the DWTS recycling process, a probe sonoreactor at a frequency of 25 kHz was used to solubilize the organics at varied specific energies. The coagulation behavior related to NOM removal in recycling the sonicated DWTS with and without solubilized organics was evaluated, and the effect on organic fractionations in coagulated water was determined. The study results could provide useful implications in designing DWTS recycling processes that avoid the enrichment of organic matter. Our results indicate that DWTS was disrupted through a low release of soluble chemical oxygen demand (SCOD) and proteins, which could deteriorate the coagulated water quality under the specific energy of 37.87–1212.1 kW h/kg TS. The optimal coagulation behavior for NOM removal was achieved by recycling the sonicated DWTS without solubilized organics at 151.5 kW h/kg TS specific energy. Recycling the sonicated DWTS could increase the enrichment potential of weakly hydrophobic acid, hydrophilic matter, and <3 kDa fractions; the enrichment risks could be reduced by discharging the solubilized organics. Fluorescent characteristic analysis indicated that when recycling the sonicated DWTS without solubilized organics, the removal of humic-like substances was limited, whereas removal of protein-like substances was enhanced, lowering the enrichment potential of protein-like substances.     

磷酸化肽富集新方法研究进展

对组成复杂的生物样品中的低丰度磷酸化肽进行预富集,能够消除高丰度非磷酸化肽等干扰组分,从而提高磷酸化肽在质谱分析中的灵敏度,获得更好的检出和鉴定结果.在磷酸化肽富集过程中,对磷酸化肽具有选择性亲和作用的富集材料是实现对磷酸化肽特异高效富集的关键,多种具有不同类型亲和作用的富集材料已在磷酸化肽富集研究中得到了应用;而在材料形貌、富集操作形式、磷酸化肽富集特异性等方面,研究者们也不断在现有磷酸化肽富集材料的基础上进行多样化的改进.本文分别从不同类型亲和作用的磷酸化肽富集材料以及磷酸化肽富集方法改进两方面,对近年来磷酸化肽富集方法的研究进展进行了评述.     

Assessing sediment pollution from the Julian Adame-Alatorre dam by instrumental neutron activation analysis

The rapid industrial development in regions of Mexico during recent years has had the side effect of introducing toxic metals, fertilizers, and pesticides into the ecosystem. Sediment cores were collected from eight locations around the Julian Adame-Alatorre dam located in the Municipality of Villanueva in the State of Zacatecas, México. The cores were analyzed for 32 major, trace, and rare earth elements (As, La, Lu, Nd, Sm, U, Yb, Ce, Co, Cr, Cs, Eu, Fe, Hf, Rb, Sb, Sc, Sr, Ta, Tb, Th, Zn, Zr, Al, Ba, Ca, Dy, K, Mn, Na, Ti, and V) in order to estimate the health risk. The samples were analyzed by instrument neutron activation analysis (INAA) using thermal neutron fluxes of 8 × 10¹³ and 5 × 10¹³ n cm⁻² s⁻¹ for short and long irradiations, respectively. The results of the contamination levels for elements such as As, Ba, Cr, Fe, Mn, Ta, V, and Zn were compared with the Mexican regulations and the guidelines of USEPA. Enrichment factors for quantified elements identified high As, Sb, Hf, and Cs contents using Fe as a crustal reference.     

EDTA-纤维微柱同时富集多种痕量元素以及电感耦合等离子体发射光谱法测定

制备了ＥＤＴＡ－纤维滤纸片，以此做为微柱填充物同时富集Ｆｅ、Ｃｕ、Ｚｎ、Ｖ、Ｐｂ、Ｃｄ、Ｃｏ和Ｎｉ等离子，结合电感耦合等离子体发射光谱法（ＩＣＰ－ＡＥＳ）测定。回收率为９２～１０６％。本法富集倍数为１００以上     

β－环糊精交联聚合物包结5－Br－PADAP配合物富集铜和镍的研究

β－环糊精交联聚合物包结有机显色剂２－（５－溴－２－吡啶偶氮）－５－二乙氨基苯酚所形成的配合物树脂可与多种金属离子反应生成吸附配合物。本文报道了以这种包结配合物树脂吸附富集铜与镍的有关实验条件、反应机理以及用分光光度法进行测定的研究。结果表明，在ｐＨ＝４～６的弱酸性介质中，包结树脂可以分别从稀溶液中定量吸附铜与镍。富集倍数达到５０倍（铜）与２００倍（镍）。     

树脂预浓集──电感耦合等离子体原子发射光谱在线分析痕量元素Cd、Cr、Cu、Ph、Zn

本文采用微型高效富集柱对膦酰胺树脂、Ｈ１０９树脂、苯乙烯多胺基膦酸树脂和膦酸胺混杂树脂对Ｃｄ、Ｃｒ、Ｃｕ、Ｐｈ、Ｚｎ等元素预富集性能进行了实验，并对浓集、洗脱及测定的条件进行选择，建立了一套在线的痕量元素－ＩＣＰ—ＡＥＳ多元素同时测定体系，从而大大提高了分析灵敏度，降低了检出限近一个数量级，Ｃｄ、Ｃｒ、Ｃｕ、Ｐｈ、Ｚｎ在不同树脂下的检出限分别为０．２～０．５ｎｇ／ｍｌ，０．３～０．６ｎｇ／ｍｌ，＜１．７ｎｇ／ｍｌ，１．５～２．８ｎｇ／ｍｌ，０．１～０．２ｎｇ／ｍｌ。利用此体系对贻贝、牡蛎、桃叶、茶叶等标样的分析结果与推荐值相符合。     

Surflex-Dock 2.1: Robust performance from ligand energetic modeling,ring flexibility,and knowledge-based search

The Surflex flexible molecular docking method has been generalized and extended in two primary areas related to the search component of docking. First, incorporation of a small-molecule force-field extends the search into Cartesian coordinates constrained by internal ligand energetics. Whereas previous versions searched only the alignment and acyclic torsional space of the ligand, the new approach supports dynamic ring flexibility and all-atom optimization of docked ligand poses. Second, knowledge of well established molecular interactions between ligand fragments and a target protein can be directly exploited to guide the search process. This offers advantages in some cases over the search strategy where ligand alignment is guided solely by a “protomol” (a pre-computed molecular representation of an idealized ligand). Results are presented on both docking accuracy and screening utility using multiple publicly available benchmark data sets that place Surflex’s performance in the context of other molecular docking methods. In terms of docking accuracy, Surflex-Dock 2.1 performs as well as the best available methods. In the area of screening utility, Surflex’s performance is extremely robust, and it is clearly superior to other methods within the set of cases for which comparative data are available, with roughly double the screening enrichment performance.